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EXPLORING THE INTERRELATIONSHIPS OF COGNITION AND SOCIAL
COMMUNICATION THROUGH DEVELOPMENT OF THE PROFILE OF
PRAGMATIC IMPAIRMENT IN COMMUNICATION IN INDIVIDUALS WITH
TRAUMATIC BRAIN INJURY
__________________
A Dissertation
Presented to
The Faculty of the Department
Of Psychology
University of Houston
__________________
In Partial Fulfillment
Of the Requirements for the Degree of
Doctor of Philosophy
__________________
By
Jace M. Waguspack
August, 2016
ii
EXPLORING THE INTERRELATIONSHIPS OF COGNITION AND SOCIAL
COMMUNICATION THROUGH DEVELOPMENT OF THE PROFILE OF
PRAGMATIC IMPAIRMENT IN COMMUNICATION IN INDIVIDUALS WITH
TRAUMATIC BRAIN INJURY
__________________
An Abstract of a Dissertation
Presented to
The Faculty of the Department
Of Psychology
University of Houston
__________________
In Partial Fulfillment
Of the Requirements for the Degree of
Doctor of Philosophy
__________________
By
Jace M. Waguspack
August, 2016
iii
Abstract
Deficits in social functioning are common following traumatic brain injury (TBI).
Previous research suggests that there are multiple, complex factors which underlie such deficits,
including cognition and social communication. Standardized measurement of social
communication following TBI is challenging, and often involves the use of structured rating
scales. The Profile of Pragmatic Impairment in Communication (PPIC) is one such scale that
shows promise, though it requires further development and empirical testing to improve its utility
in the TBI population. The current study is archival in nature. Data were obtained from two prior
study samples in projects investigating social communication in the community dwelling adult
TBI population: the social communication assessment measures study (SCA study, N = 121) and
a randomized clinical trial for social communication intervention (IPR study, N = 83). In order to
further develop the PPIC and examine the underlying cognitive abilities which impact social
pragmatics, the 84 behavioral items of the PPIC were reduced to a set of 20 items deemed to be
most characteristic of social communication difficulties following TBI. These 20 items were
analyzed using exploratory factor analysis. Following an iterative process, a two factor solution
accounting for 60.77% of the total variance was obtained, and it included 9 of the 20 originally
selected items. These factors were labeled Partner Sensitivity (5 items) and Conversational Flow
(4 items), and subscale scores were created by summing the item scores within each factor. The
cognitive underpinnings of social pragmatics as measured by the new PPIC subscales were
examined using hierarchical linear regression, using measures of attention, executive functioning,
and affect perception as predictor variables and the new PPIC subscale scores, AIPSS Overall
Sending score, and the TIRR Social Communication Rating Form (an experimental measure) as
outcome variables. After adjusting for demographic and injury-related variables, performance on
cognitive measures accounted for a unique 22% of the variance in PPIC Conversational Flow
scores and 17% of the variance in AIPSS Overall Sending scores, while performance on cognitive
measures did not account for a statistically significant amount of unique variance in PPIC Partner
iv
Sensitivity scores or TIRR Social Communication Rating Form scores. These results represent
important preliminary steps in the development of the PPIC into a more parsimonious and useful
tool and in developing a more sophisticated understanding of the relationship between cognition,
social communication, and social functioning in TBI.
v
ACKNOWLEDGMENTS
I would like to thank Dr. Hannay for her time, guidance, and encouragement throughout
my graduate school career. Her commitment to teaching and mentorship has played a crucial role
in my education and professional development, and I owe her my sincerest gratitude. I would also
like to thank Dr. Struchen for serving as my committee co-chair. Her willingness to take on the
additional responsibility of guiding a student through the dissertation process allowed me to
pursue an area of research that I am fascinated by and passionate about, and I am extremely
grateful for her time and help. Additionally, I would like to thank Drs. Massman, Pappadis, and
Steinberg for serving on my committee, and for being gracious with their time, expertise, and
support. Finally, I would like to thank my wife, Jessica, and my family. Their love and support
provided me with the strength and determination to finish this race. Thank you all.
vi
TABLE OF CONTENTS
Chapter 1: Background and Literature Review ................................................................................ 1
Overview of Traumatic Brain Injury ............................................................................................. 1
Injury Severity .............................................................................................................................. 2
Cognitive and Behavioral Changes Following TBI ........................................................................ 4
Social Functioning and Social Cognition in TBI ............................................................................ 6
Relationship between Social Cognition and other Cognitive Domains in TBI ............................. 8
Social Communication in TBI ....................................................................................................... 8
The Profile of Pragmatic Impairment in Communication .......................................................... 12
Present Problem ........................................................................................................................ 17
Hypotheses of the Current Study .............................................................................................. 18
Chapter 2: Methods ....................................................................................................................... 21
Participants & Procedures ......................................................................................................... 21
Measures.................................................................................................................................... 25
Statistical Analyses ..................................................................................................................... 30
Chapter 3: Results .......................................................................................................................... 33
Sample Characteristics ............................................................................................................... 33
Specific Aim 1: PPIC Development ............................................................................................. 33
Specific Aim 2: Prediction of Social Communication Difficulties ............................................... 40
Chapter 4: Discussion ..................................................................................................................... 46
Specific Aim 1: PPIC Development ............................................................................................. 46
Specific Aim 2: Prediction of Social Communication Difficulties ............................................... 48
Study Limitations & Future Directions ....................................................................................... 53
Conclusion .................................................................................................................................. 56
APPENDIX A Figures and Tables ..................................................................................................... 58
APPENDIX B Distribution Histograms, P-P Plots, and Scatterplots ................................................ 72
Partner Sensitivity Regression Residual Plots ............................................................................ 72
Conversational Flow Regression Residual Plots ......................................................................... 72
TIRR Social Communication Rating Form Regression Plots ....................................................... 73
AIPSS Regression Plots ............................................................................................................... 73
REFERENCES ................................................................................................................................... 74
vii
LIST OF TABLES
Table 1. Hypothesized Factor Structure for Selected PPIC Items……………………….51
Table 2. Predictor and Outcome Variables for Specific Aim 2………………………….52
Table 3. Comparison of Demographic Characteristics
and Key Measures of the SCA and IPR Participants……………...53
Table 4. Correlations Among PPIC Items………………………………………….……54
Table 5. Varimax Rotated Principal Axis Factoring Loadings and Communality
Estimates for PPIC (3 Factors).……………………………….....55
Table 6. Varimax Rotated Principal Axis Factoring Loadings and Communality
Estimates for PPIC (2 Factors)……………………………….....55
Table 7. Descriptive Statistics for Social Communication and Community
Integration Measures…………………………………………...56
Table 8. Descriptive Statistics for Predictor and Outcome Measures……………….....57
Table 9. Correlations Among Predictor and Dependent Variables………………….....58
Table 10. Prediction of PPIC Partner Sensitivity Scale Scores……………………......59
Table 11. Prediction of PPIC Conversational Flow Scale Scores……………...……...60
Table 12. Prediction of TIRR Social Communication Rating Form Scores………......61
viii
Table 13. Prediction of AIPSS Overall Sending Scores……………………...………62
Figure 1. PPIC Item Selection Process…………………………………………….....63
COGNITION AND SOCIAL COMMUNICATION IN TBI
1
Chapter 1: Background and Literature Review
Overview of Traumatic Brain Injury
Traumatic brain injury (TBI) is one of the leading causes of disability in the
United States today (Faul, Xu, Wald, & Coronado, 2010). In the year 2000, the estimated
total cost of TBI was $60 billion (Finklestein et al., 2006), and there are approximately
1.7 million reported TBI’s annually (Faul et al., 2010). TBI is defined as injury to the
brain due to an external mechanical force, and common causes include motor vehicle
collisions (MVCs), falls, and assaults (Faul et al., 2010).
Each TBI is different due to a variety of factors (e.g., magnitude and direction of
forces, composition of object impacted). In a closed traumatic brain injury, the brain is
damaged through an external mechanical force but the brain and meninges are not
penetrated by skull fragments or external objects (Lezak, Howieson, Bigler, & Tranel,
2012). Certain brain regions are especially susceptible to TBI. In particular, the frontal
and temporal lobes are often damaged due to the boney ridges that protrude from the base
of the skull and the brain’s tendency to scrape and tear against these during rapid
deceleration and frontal impact (Fork et al., 2005). Diffuse axonal injury (DAI) is also
common following closed TBI, especially when the injury is sustained at high velocities
(i.e. in motor vehicle collisions) (Levine et al., 2008). In such cases, DAI occurs from
rotational acceleration/deceleration forces which cause tearing and shearing of axons
which comprise the sub-cortical white matter (Sidaros et al., 2008). Not surprisingly,
many of the cognitive and behavioral impairments typically seen in closed TBI patients
are correlated with these pathologies.
COGNITION AND SOCIAL COMMUNICATION IN TBI
2
Injury Severity
One heavily researched topic within traumatic brain injury involves the
classification, application, and impact of initial injury severity. While the methods used
to define injury severity vary widely in the research literature, the most commonly used
variables include Glasgow Coma Scale score (GCS, Teasdale & Jennett, 1974), length of
coma (LOC), duration of post-traumatic amnesia (PTA), pupillary response, and presence
and severity of intracranial abnormalities detected by CT scans (Sherer et al., 2008).
While some classification schemes differ, head injury severity is generally categorized as
mild, complicated mild, moderate, and severe (Van Baalen et al., 2003). Severe TBI is
thought to account for approximately 10% of documented TBIs, while moderate and
complicated mild injuries account for an additional 10%, and mild injuries account for
the remaining 80% of documented injuries (Bruns & Hauser, 2003). It is noted, however,
that estimating the prevalence of mild head injuries is difficult, as many of these
individuals never seek medical treatment (Langlois, Rutland-Brown, & Wald, 2006).
When determining injury severity using the GCS, researchers and clinicians
typically define severe TBI as a GCS score of 3-8, moderate TBI as 9-12, and
mild/complicated mild TBI as 13-15 (Rimel et al., 1982) although this subdivision is
somewhat artificial and can result in misclassification of patients in terms of their clinical
characteristics (Maas et al., 2012; Sherer et al., 2008). Currently, inconsistency exists
regarding which GCS score for a given patient defines their injury severity (American
Academy of Neurological Surgeons, 2000). The most commonly used GCS scores are the
ER admission GCS, the worst GCS during the 24 hours following injury, and the best
GCS during the 24 hours following injury (Sherer et al., 2008). Each of these methods
COGNITION AND SOCIAL COMMUNICATION IN TBI
3
has limitations and can lead to over- or underestimations of injury severity (Lezak et al.,
2012; Sherer et al., 2008).
Duration of post-traumatic amnesia (PTA) is another injury severity indicator that
is commonly used. Most researchers define PTA duration as the length of time between
when a patient can consistently follow commands and when the patient shows consistent
orientation and reliable formation of new episodic memories (Sherer et al., 2008). Of
course, when PTA ends and more permanent memory loss begins is not always easy to
determine (Wilson et al., 1999).
PTA duration has been linked to functional outcome in the TBI population and
has utility as a reliable prognostic indicator (Walker et al., 2008). According to a
commonly used schema developed by Russell and Smith (1961), PTA duration of less
than 1 hour is indicative of mild TBI, 1-24 hours is considered to be a moderate TBI, 1-7
days represents a severe TBI, and PTA duration of greater than 7 days is considered a
very severe TBI. More recent research lends support to a different PTA classification
scheme known as the Mississippi PTA Intervals (Nakase-Richardson et al., 2009). Under
this classification scheme, PTA duration of 0-14 days is considered to be a moderate TBI,
15-28 days is considered to be a moderate severe injury, 29-70 days is considered to be a
severe injury, and PTA duration of greater than 70 days is considered to be extremely
severe (Nakase-Richardson et al., 2009). While research has shown that PTA duration is
significantly correlated with initial GCS score, disparity between these two severity
variables exists (Sherer et al., 2008). The GCS is useful in predicting morbidity and
mortality during the acute phase of TBI (Sherer et al., 2008), whereas PTA duration is
more useful as a severity indicator for later outcome (Walker et al., 2010).
COGNITION AND SOCIAL COMMUNICATION IN TBI
4
Cognitive and Behavioral Changes Following TBI
There are several common cognitive and behavioral problems that many
individuals face after TBI, and not surprisingly these tend to correspond to the areas of
the brain discussed above. Deficits in executive function, memory, word finding,
attention, and processing speed are all common following TBI (Rios et al., 2004;
Spikman, Deelman, & van Zomeran, 2000; Spikman et al. 2012).
Deficits in attention and cognitive processing speed are some of the most
consistently documented impairments following TBI. As previously mentioned, many
TBIs result in DAI, particularly when the injury involves the rapid
acceleration/deceleration forces often present in motor-vehicle accidents. DAI has been
associated with deficits in attention and processing speed, likely due to the disruption of
connections between different brain regions (Bonnelle et al., 2011; Felmingham,
Baguley, & Green, 2004; Scheid et al., 2006). These deficits in attention and cognitive
processing speed are associated with poorer functional outcome (Ponsford, Draper, &
Schonberger, 2008; Spitz et al., 2012).
Many TBI patients also experience memory impairments as well, which can affect
the acquisition as well as the retrieval of information (Dikmen, Machamer, and Temkin,
2009). These impairments have been associated with damage to the temporal lobes,
which are vulnerable during TBI (Lezak et al., 2012). Poor performance on measures of
memory has been associated with poor functional outcome, particularly regarding return
COGNITION AND SOCIAL COMMUNICATION IN TBI
5
to productivity (Boake et al., 2001), whereas intact performance on memory measures is
associated with an increased likelihood of returning to work (Hanlon et al., 1999).
Language deficits in individuals with TBI may vary due to the locations and
severity of the injury. While aphasic syndromes are rare in TBI, these patients often
exhibit difficulties in word-finding and naming (Levin, 1991). Impaired verbal fluency is
also common (Ponsford, Draper, & Schonberger, 2008). It is important to note that these
language disturbances are distinct from communication skills, which requires the
individual to use language effectively for different purposes depending on the nature of a
conversational exchange (Prigatano, Roueche, & Fordyce, 1985). This distinction will be
discussed in greater detail elsewhere.
Executive dysfunction is one of the most common and debilitating cognitive
impairments frequently present following TBI (Spikman, Deelman, & Zomeren, 2000).
As mentioned previously, the pre-frontal cortex and white matter connections are
particularly vulnerable to TBI, and damage to these structures is associated with
executive dysfunction (Spikman et al., 2000). Rather than a discrete cognitive process,
executive functioning is an umbrella term that includes planning and organization,
problem solving, initiation of goal-directed activity, impulse control, working memory,
self-awareness, and emotion regulation (Lezak, 1982). Deficits in these abilities are
associated with a number of poor outcomes, including decreases in productive activity
and impairments in social functioning (Boake et al., 2001; Spikman et al., 2000; Struchen
et al., 2008).
COGNITION AND SOCIAL COMMUNICATION IN TBI
6
Behavioral issues may include irritability, personality change, and disinhibition
(Spikman et al., 2012; Warriner, Rourke, Velikonja, & Metham, 2003). Not surprisingly,
these issues are thought to contribute to a variety of difficulties for an individual who has
sustained a TBI, including impaired social functioning.
Social Functioning and Social Cognition in TBI
Evidence suggests that individuals who have sustained traumatic brain injuries
experience an increased degree of social isolation and impaired social functioning
following injury (Hoofien et al., 2001; Marsh, Kersel, Havill, & Sleigh, 2002). This can
have an adverse impact on a person’s subjective experience of quality of life, their
productivity during and after recovery, and the amount of strain or burden placed upon
caregivers (Marsh et al., 2002). There are a number of factors thought to contribute to
and exacerbate social functioning impairments following TBI. Cognitive impairments
and behavioral changes following injury are thought to impact an individual’s ability to
function effectively in social situations negatively (Spikman et al., 2012). In addition to
the cognitive problems that have already been discussed, more recent research has begun
to examine the role of social cognition in effective social functioning. Social cognition
refers to “the mental operations that underlie social interactions, including perceiving,
interpreting, and generating responses to the intentions, dispositions, and behavior of
others” (Green et al., 2008 p. 1211). Recent research points to the existence of two
related social cognitive systems in the human brain (Frith & Frith, 2010). “Cold” social
cognition refers to the mentalizing abilities necessary for theory of mind (Adolphs, 2010;
McDonald, 2013). Theory of mind refers to the ability to infer the mental states of others
and then make predictions about their behavior (Bibby & McDonald, 2005). “Hot” social
COGNITION AND SOCIAL COMMUNICATION IN TBI
7
cognition refers to the ability to understand the mood states of others and empathize with
them (Adolphs, 2010, McDonald, 2013;).
Not surprisingly, it has been discovered that an individual’s social cognitive
functioning has an impact on their ability to effectively function in social situations
(Couture, Penn, & Roberts, 2006; Struchen et al., 2008). In fact, there is research
indicating that social cognition has a greater impact on social functioning and social
communication than does “neuro-cognition” (i.e. memory, language, attention, executive
functioning, etc) in individuals with schizophrenia, (Penn, Spaulding, Reed, & Sullivan,
1996; Pinkham & Penn, 2006; Roncone et al., 2002), and this finding appears to be
supported in the TBI population as well (Struchen et al., 2008).
In recent years, social cognition (particularly facial emotion recognition and
theory of mind) has become a subject of interest among TBI researchers. Facial emotion
perception is the ability to accurately infer the mood state of others based on affective
facial cues (Bornhofen & McDonald, 2008). Studies have consistently documented
impaired performance on measures of emotion recognition (Henry et al., 2006; Ietswaart
et al., 2008; Spikman et al., 2012) and theory of mind (Henry et al., 2006; Muller et al.,
2010; Spikman et al., 2012) in patients with moderate and severe traumatic brain injury
relative to control subjects. Moreover, these deficits are enduring, and have been
observed in moderate and severe TBI patients both soon after injury and up to a year
post-injury (Ietswaart et al., 2008). Research indicates that a collection of brain
structures forms a social cognitive circuit, which is involved in various aspects of
processing social situations and cues; this circuit includes the amygdale, fusiform gyrus,
superior temporal sulcus, and prefrontal cortices (Pinkham et al., 2003). Given the
COGNITION AND SOCIAL COMMUNICATION IN TBI
8
pervasiveness of frontal lesions and axonal injury in moderate and severe TBI, it is no
surprise that deficits in social cognitive abilities are also observed in these individuals.
Research has also directly examined severity of social cognitive deficits and presence of
pre-frontal lesions, and it was observed that impairments in facial emotion recognition in
particular were associated with pre-frontal lesions, though the authors do note that this
effect was somewhat accounted for by injury severity (Spikman et al., 2012).
Impairments in social cognition following TBI have been linked to worse social
(Bornhofen & McDonald, 2008; Struchen et al., 2008) and occupational (Struchen et al.,
2008) functioning.
Relationship between Social Cognition and other Cognitive Domains in TBI
A number of studies have focused on the relationship between social cognitive
deficits and other, more general cognitive deficits following TBI. The results of these
studies indicate that social cognition is distinct from other cognitive domains impacted by
TBI (McDonald 2013; Spikman et al., 2012). However, the two are related, and cognitive
deficits can have an impact on social cognitive processes. Specifically, performance on
measures of verbal and non-verbal memory, working memory, attention, and processing
speed predict facial affect recognition ability in patients with TBI (Yim et al., 2013).
Furthermore, impairments in executive functioning have been associated with theory of
mind deficits in patients with TBI (Dennis et al., 2009; Henry et al., 2006).
Social Communication in TBI
Related to the study of social cognition in TBI is the investigation of social
communication following TBI. Social communication abilities can be defined as “both
verbal and nonverbal skills that allow one to be able to understand others and what others
COGNITION AND SOCIAL COMMUNICATION IN TBI
9
mean to communicate, as well as to express oneself to others in a manner that conveys
the intended meaning” (Struchen et al., 2011).
According to an information processing model advocated by Richard McFall
(1982), social communication can be divided into three distinct stages. The first is the
decoding stage, during which the conversational participant receives, perceives, and
interprets a message. Receiving involves the actual detection of the incoming information
via the appropriate sensory modality (i.e. hearing or sight). Perceiving entails
transforming the raw sensory data into information that can be stored in short term
memory for use by the individual. McFall notes that a breakdown in perceiving could be
the result of inattention or distractibility, two problems commonly experienced in
individuals with TBI. Interpretation requires the individual to judge and apply meaning to
the message received given the current context. Within the framework of McFall’s
model, social cognitive abilities such as emotion perception and theory of mind take
place primarily at the level of interpretation.
The second stage of McFall’s model is the decision stage. During this stage of
communication, the individual who has received a message must generate adequate
responses, test those responses against the demands of the conversational context and
environment, select the most appropriate response, and evaluate the risks and utility of
giving the selected response. McFall posits that deficits in this set of skills may result in
suboptimal social communication, which could range from impulsive behavior to overly
conservative or restricted behavior.
COGNITION AND SOCIAL COMMUNICATION IN TBI
10
The final stage of McFall’s model is the encoding stage, which include the skills
of execution and self-monitoring. Execution involves an individual’s ability to effectively
translate his/her selected response into action to emit the intended message. Self-
monitoring refers to the individual’s ability to monitor any discrepancies between the
intent of the message and the actual impact of the message, and make behavioral
adjustments accordingly. Poor execution may manifest itself as unintentionally
ambiguous or confusing verbal or non-verbal behaviors that confound the intended
message, while poor self-monitoring may result in an individual not realizing that a
message was rude or inappropriate in the conversational context.
Effective use of these social communication skills is often impaired following
TBI, even in the absence of aphasia or other specific language disturbances (Soulberg &
Mateer, 1988; Struchen et al., 2011). Two specific areas within social communication
that have received attention are discourse analysis and social pragmatics. Discourse refers
to the syntactical and linguistic characteristics of sent messages during a conversation
(Coelho, 1999). Discourse types may include descriptive, narrative, procedural,
persuasive, expository, and conversational discourse (Coelho, 1999). These
characteristics can be quantified and examined in various ways through the process
known as discourse analysis. Common discourse analysis methods include
microlinguistic analyses (phonologic and/or lexical production, syntax), macrolinguistic
analyses (cohesion, story structure, and coherence), and miscellaneous analyses
(productivity, rating scales, response appropriateness/relevance, compensatory strategies,
analysis of topic, and content analysis) (Coelho, 1999). Numerous discourse deficits are
routinely observed following TBI. Specifically, impairments in discourse production,
COGNITION AND SOCIAL COMMUNICATION IN TBI
11
cohesion, story structure, and coherence have been observed (Coelho, 1999). Some
researchers have suggested that these deficits, particularly in cohesion and story structure,
are related to executive dysfunction (Coelho, 1999; Coelho, Liles, & Duffy, 1995;
Ylvisaker & Szekeres, 1989).
In addition to discourse deficits, impairments in social pragmatics are common
following TBI. In the context of social communication and TBI, many researchers have
used the term to refer to the employment of communication skills which supersede basic
linguistic abilities (Perkins, Body, & Parker, 1995), or the use of basic linguistic abilities
and other communication behaviors in interpersonal interactions (Milton, Prutting, &
Binder, 1984). Impairments in these social communication abilities may lead to
inadequate contribution to conversation, difficulties in topic maintenance, or being
tangential, inappropriate, or over-talkative (Struchen et al., 2011). Not surprisingly,
researchers have demonstrated associations between executive functioning, social
communication abilities, and social functioning outcomes (Struchen et al., 2008). Studies
of social pragmatics in the TBI population generally attempt to quantify the use and
misuse of certain communication behaviors during interpersonal interactions using rating
scales for various communication behaviors or self-report measures of interpersonal
communication style and effectiveness (Body, Perkins, & McDonald, 1999).
One such self-report measure of interpersonal communication effectiveness is the
La Trobe Communication Questionnaire (LCQ; Douglas, O’Flaherty, & Snow, 2000).
The LCQ was originally developed to measure perceived communication difficulties in
adults following TBI. Thirty items were developed following Damico’s analysis of
discourse categories (Damico, 1985) and Grice’s theory of conversational maxims (Grice,
COGNITION AND SOCIAL COMMUNICATION IN TBI
12
1975). A recent study by Struchen et al. (2008) further examined the LCQ using principal
components analysis. Results of these analyses yielded 4 factors comprised of 27 of the
30 LCQ items, which the researchers labeled Initiation/Conversational Flow,
Disinhibition/Impulsivity, Conversational Effectiveness, and Partner Sensitivity
(Struchen et al., 2008). LCQ scores have been found to be predictive of social integration
outcomes following TBI (Struchen et al., 2011).
In addition to self-report measures of communication effectiveness, measures of
researcher/clinician rated social communication have been created and utilized. The use
of these measures provides researchers and clinicians with a standardized tool that can be
used to more directly observe impairments in social pragmatics following TBI. One such
rating scale is the Profile of Pragmatic Impairment in Communication.
The Profile of Pragmatic Impairment in Communication
The Profile of Pragmatic Impairment in Communication (PPIC), formerly known
as the Profile of Functional Impairment in Communication (PFIC; Linscott, Knight, &
Godfrey, 1996) is a standardized rating form that was created to assess communication
difficulties during an unstructured discourse sample in individuals who had sustained a
traumatic brain injury. The measure consists of 84 individual behavioral items assessing
various aspects of social communication, and these items were grouped into 10 “feature
summary scales” (Linscott et al., 1996). These scales are logical content, general
participation, quantity, quality, internal relation, external relation, clarity of expression,
social style, subject matter, and aesthetics.
COGNITION AND SOCIAL COMMUNICATION IN TBI
13
When initially designing the measure, the creators of the PPIC examined common
communication difficulties following TBI reported in the literature and formulated the 84
individual behavioral items to capture these impairments (Linscott et al., 1996). Then, the
behavioral items were organized into feature summary scales based on Grice’s model of
communication theory (Grice, 1975). Grice’s model posits that there are four maxims of
conversation that must be followed for successful communication. These maxims are
quantity, quality, relevance, and manner (Grice, 1975). A summary of Grice’s maxims is
provided by Body, Perkins, and McDonald (1999, p 83-84). The maxim of quantity states
that conversational participants say no more or no less than is needed to effectively
communicate their intended message. The maxim of quality states that conversational
participants should not say anything that they believe is false or for which they lack
supporting evidence. The maxim of relevance states that a conversational participant’s
comments should be relevant to the topic at hand. The maxim of manner states that
conversational participants should be concise and organized in their communication
without being obscure or ambiguous. The authors of the PPIC elaborated on Grice’s
model to include pragmatic aspects of communication not directly addressed in the
model, such as aesthetics (i.e. pauses, gestures, volume) and subject matter (i.e.
appropriateness of the topic for the conversation) (Linscott et al., 1996).
The rater watches a videotaped 10-15 minute session of the participant having an
unstructured conversation with a research confederate and scores each behavioral item
within a feature summary scale on a 4-point Likert scale ranging from 0 (not at all) to 3
(nearly always or always). Using the ratings on the behavioral items within each feature
summary scale as a guide, the rater then ranks the participant’s overall proficiency in that
COGNITION AND SOCIAL COMMUNICATION IN TBI
14
domain of communication on a 6-point Likert scale ranging from normal (0) to very
severely impaired (6). This overall proficiency rating is the feature summary scale score,
regardless of ratings of individual behavioral items within the scale.
In the original PPIC study, 20 participants were selected from a larger TBI sample
based on their perceived level of social communication proficiency. The researchers
selected 10 participants whom they subjectively rated as having the greatest social
communication impairments and 10 participants rated as having the least social
communication impairments. All participants had sustained a severe TBI as defined by a
period of PTA lasting between 24 hours and 10 weeks. The researchers then trained 8
raters to use the PPIC who were blinded to the original ratings of the participants’ social
skill proficiency. After rating each 15 minute conversation with the PFIC, the raters were
given a short survey designed to assess the face validity of the measure. Analysis of the
data revealed a significant effect of group (TBI patients previously rated as most vs least
impaired) and rater, though the researchers reported no group X rater interaction
(Linscott et al., 1996). The high-skill TBI group performed significantly better across
most PPIC summary scales than did the low-skill TBI group.
The reliability of the PPIC was examined by calculating intra-class correlation
coefficients within raters (0.43 to 0.64), between two raters (0.75-0.88), and across all
eight raters (0.86 to 0.94), and the authors concluded that the feature summary scales
demonstrated good inter-rater reliability. Statistical significance for these coefficients
was not reported in this study. In order to examine concurrent validity, the examined
associations between group membership and feature summary scale scores. All feature
summary scale scores were significantly correlated with group membership as were
COGNITION AND SOCIAL COMMUNICATION IN TBI
15
logical content, general participation, and external relation scores (r > .94, p < 0.05)
(Linscott et al., 1996). Based on the results of surveys taken by the raters, the authors
concluded that the PPIC exhibited strong face validity, as it was rated as a good measure
of communication, practical, and comprehensive by the 8 raters.
Since its development, the PPIC has been used in a small number of TBI and
social communication studies. Godfrey et al. (2000) used the PPIC in a small pediatric
TBI population to examine the utility of the PPIC in characterizing social communication
impairments exhibited during a family problem solving discussion in a pediatric sample.
When comparing the performance of the TBI participants on the PPIC to performance of
11 matched orthopedic control participants, the TBI group performed significantly worse
on the quality, internal relation, clarity of expression, social style, subject matter, and
aesthetics feature summary scale scores (Godfrey et al., 2000). Furthermore, performance
was correlated with injury severity (determined using PTA duration) for all feature
summary scale scores except quantity. It is important to note, however, that the
conversational sample used to obtain PPIC scores in this study was based on a family
problem-solving discussion rather than an unstructured conversation. As the PPIC was
initially created and developed using unstructured conversational samples, the use of a
different conversational paradigm in this study may limit the generalizability of the
findings to other studies using the PPIC.
Dahlberg et al. (2006) conducted a study on social communication impairments in
TBI in which they utilized the PPIC as a clinician-rated estimate of participants’ social
communication ability, and compared this to the participants’ or their significant others’
estimate of the participants’ social communication ability. The researchers identified 7
COGNITION AND SOCIAL COMMUNICATION IN TBI
16
behavioral items for which the TBI participants’ mean score was 1.5 or higher,
interpreted as being indicative of at least occasional difficulty in that area (Dahlberg et
al., 2006). These behavioral items were as follows: asks questions, perceives
misinterpretation of meaning, uses questions well, skilled at taking turns, integrates own
ideas with other’s ideas, contributes equally to the conversation, and helps direct the
conversation. When examining TBI participants’ performance on feature summary
scales, participant scores were mildly impaired on the social style, aesthetics, internal
relation, and external relation scales. Participant scores for the general participation
summary scale fell within the moderately impaired range (Dahlberg et al., 2006).
The PPIC has also been used as a primary outcome measure in several clinical
trials. Dahlberg et al. (2007) conducted a randomized clinical trial focused on
improvement of social communication skills following TBI. Participants in the treatment
group showed significant treatment effects on 7 of the 10 PPIC summary scales when
compared to the deferred treatment group. In a similar study, Braden et al. (2010) found
that PPIC summary scores showed a trend towards improvement over time following
treatment. The PPIC has also been used in other clinical trials aimed at remediation of
social communication skills (Struchen et al., in preparation), though in contrast to the
previously mentioned studies no significant improvement was observed in global PPIC
scores.
The PPIC’s creation was theory driven, based on the Grice models of
communication. Items were included to assess all possible communication difficulties
that may be encountered after TBI according to this model. There are no published
studies known to this author which involve a factor analysis of the PPIC items to
COGNITION AND SOCIAL COMMUNICATION IN TBI
17
determine whether the theoretically derived structure of the measure (i.e. the 10 feature
summary scales) is empirically supported. And, many of the PPIC’s behavioral items
occur with low frequency in the broader TBI population and may or may not be
discriminative or helpful in terms of an evaluation that leads to useful recommendations
for rehabilitation. Despite these limitations, the PPIC has been adopted for use in several
clinical trials targeting remediation of social communication skills in TBI patients due to
the lack of other suitable published measures. The absence from the literature of other
tools for clinician-rated measurement of social pragmatic communication skills highlights
the need for further development of the PPIC.
Present Problem
Further development of the PPIC into a more manageable empirically based
instrument would provide researchers and clinicians with a structured, practical tool for
the assessment of important social communication difficulties after TBI. Also,
development of an outcome measure that is more parsimonious increases the number of
statistical analyses that can be performed with the limited sample sizes that are often
typical of TBI outcome research. A streamlined measure also may enable further
exploration of the relationships between cognition and social communication. Examining
the cognitive mechanisms that may underlie social communication difficulties further
informs an understanding of abilities that are important for successful conversational
interaction and may yield viable targets for intervention and development of possible
compensatory strategies in future research.
Development of the PPIC presents a number of methodological challenges. First,
in order to conduct a proper factor analysis of the PPIC items and investigate whether the
COGNITION AND SOCIAL COMMUNICATION IN TBI
18
theoretical structure designed by the original researchers is empirically supported, an
extremely large sample would be needed (between 420 and 840 participants to maintain
the conventional guideline of 5-10 participants per variable). Furthermore, there is no
accepted “gold standard” measure known to the author at this time for the measurement
of social pragmatics in an unstructured conversational paradigm. The lack of similar
measures for comparison makes establishing the validity of the PPIC difficult. Given
these methodological challenges and the current sample of 204 participants, it was
decided that the author would select items most characteristic of social communication
problems following TBI. Review of the relevant literature, group discussion with experts
in measure development and TBI research, and the author’s own clinical and research
experience with TBI patients were used to guide the item selection process.
Hypotheses of the Current Study
Specific aim 1. The first aim of the current study was to examine the reliability,
validity, and factor structure of the twenty behavioral items from the PPIC that were
selected by the author as most characteristic of social communication problems after TBI
through exploratory factor analysis. An exploratory factor analysis of these twenty items
was conducted. Based on results of the exploratory factor analysis, other specific
hypotheses about the relationships between performance on cognitive measures and new
factor scores of the PPIC were created and then tested. Analyses designed to establish
preliminary evidence for criterion-related and construct validity of the revised PPIC were
also conducted.
Hypothesis 1a. The hypothesized factor structure for the revised PPIC is presented
in Table 1. It was predicted that the resulting factors would represent different aspects of
COGNITION AND SOCIAL COMMUNICATION IN TBI
19
social communication as measured by the PPIC, but that they would be modestly
correlated with one another due to the expected relatedness of different aspects of social
communication.
Hypothesis 1b. In order to provide preliminary evidence of criterion-related
concurrent validity for the PPIC revisions, the newly developed factor structure was
compared to social functioning outcome measures, as previous research has provided
evidence of a relationship between social communication and social functioning
outcomes. It was predicted that the factor scores of the revised PPIC would be correlated
significantly with measures of social functioning and community integration.
Hypothesis 1c. In order to provide preliminary evidence of convergent construct
validity for the PPIC revisions, the newly developed factor scores for participants were
compared to established and experimental measures which involve demonstrating social
communication skills.It was hypothesized that the factor scores of the revised PPIC
would be related to these measures, with better performance on the PPIC correlating with
better performance on other measures of social communication.
Specific aim 2. The second aim of the current study was to examine the
relationship between performance on measures of attention/executive functioning and
affect perception and proficiency to social communication.Table 2 contains a summary of
predictor and outcome variables.
Hypotheses 2a-2c. Performance on measures of attention/executive functioning
and social cognition were expected to account for a significant amount of the variance in
performance on social communication measures, above that accounted for by
COGNITION AND SOCIAL COMMUNICATION IN TBI
20
demographic and injury related variables. Specifically, poorer performance on measures
of attention/executive functioning and affect perception would be predictive of worse
social communication. Based on previous research (Struchen et al., 2008), it was
expected that modest to strong relationships between measures of affect perception and
executive functioning would be present. Conceptually, social communication requires an
individual to rapidly alternate between processing incoming messages and formulating
appropriate responses to these messages, which requires accurate perception and
interpretation of the affective and social cues being received as well as some proficiency
in set-switching and multi-tasking. It was therefore anticipated that performance on
measures of mental flexibility and affect perception would make a statistically significant
unique contribution to the explanation of the variance in social communication
performance.
Purpose of the Current Study
The purpose of the current study is to develop the PPIC into a more practical and
parsimonious measure of social communication proficiency for the TBI population.
Doing so not only assists in the investigation of social communication difficulties
following TBI, it facilitates exploration of the neuro- and social-cognitive processes that
underlie these social communication difficulties. The current study investigates the
contributions of select measures of attention, executive functioning, and affect perception
to social communication impairments following TBI.
COGNITION AND SOCIAL COMMUNICATION IN TBI
21
Chapter 2: Methods
Participants & Procedures
Approval for this study was obtained from the Committee for the Protection of
Human Subjects (CPHS) of the Institutional Review Board (IRB) at the University of
Houston. Data for this archival study were collected originally for research grants and
studies at TIRR Memorial Hermann with the approval of and in compliance with
regulations mandated by the CPHS of the IRB at Baylor College of Medicine (BCM).
Permission for the use of these data was obtained from the appropriate investigator in a
letter that supplied the current protocol number(s) from the BCM IRB for the database(s)
storage. Data from 204 participants with TBI were included in the analyses for Specific
Aim 1. Persons with TBI were included from one of two studies: 121 participants who
had been recruited from participants of the local National Institute for Disability and
Rehabilitation Research TBI Model System (NIDRR-TBIMS) sample to participate in a
separate project designed to evaluate social communication assessment measures (SCA
study) and 83 were participants recruited from a randomized clinical trial of a social
communication intervention (IPR study). For Specific Aim 2, only participants from the
SCA study (N=121) were included as the cognitive measures were not administered for
participants in the IPR study.
Persons participating in the SCA study were drawn from the overall sample of
NIDRR-TBIMS participants at the local rehabilitation site in the Southern US. Criteria
for inclusion in the Model Systems study included: diagnosis of TBI resulting in
admission to the emergency department of a Model Systems hospital between 8-24 hours
post-injury; aged > 16 years; acute care and inpatient rehabilitation received within the
COGNITION AND SOCIAL COMMUNICATION IN TBI
22
Model System facilities; residence in a designated catchment area; and provision of
informed consent by the person with injury or a family member.
Participants in the SCA study and/or their family member or legally authorized
representative signed a separate consent form to participate in a study to evaluate social
communication abilities. Additional inclusion criteria for that study restricted participants
to those aged 18 years or older and excluded those with severe communication deficits
(e.g., global aphasia), inability to communicate, prior central nervous system dysfunction
that might impact cognition (e.g., stroke, brain tumor), and severe psychiatric disorder
(e.g., schizophrenia, schizoaffective disorder). Persons with mild language impairments
such as anomia were not excluded from participation, nor were participants with
psychiatric disorders that did not include psychotic features (e.g., major depression,
generalized anxiety disorder, etc.).
For the SCA study participants a testing session was scheduled at the research
facility. During this session, they were administered a series of structured interviews,
self-report questionnaires, measures of executive functioning, and social communication
measures, including the measures used in the current study.
Participants for the IPR study were recruited from the following sources: 1)
individuals with TBI admitted to a comprehensive inpatient brain injury rehabilitation
program in a rehabilitation hospital, 2) individuals with TBI admitted to an inpatient
rehabilitation program within a county hospital setting, and 3) individuals who had
participated in previous research projects who had provided written assent to be contacted
for future research studies. Participants recruited for prior studies were also initially
recruited from consecutive admissions to either a Level 1 trauma center or to an inpatient
COGNITION AND SOCIAL COMMUNICATION IN TBI
23
brain injury rehabilitation program. Given this method of recruitment, there was some
overlap of participants between the SCA study and the IPR study (N = 25 participated in
both studies). For purposes of the this study, if a participant had participated in both
former studies, only data obtained in the SCA study was included in analyses to avoid
oversampling of any given individual participant in proposed analyses.
Inclusion and exclusion criteria for consenting and/or consented participants for
the previous IPR study are presented below. All participants had a traumatic brain injury,
as documented by medical records. Participants were recruited at the time of admission at
the respective rehabilitation sites, or through in-person conversations scheduled after
contacting potential participants by phone or letter. Given that one of the inclusion
criteria was participation in an inpatient rehabilitation program, persons with complicated
mild, moderate, and severe TBI were included in the study, and the majority of patients
sustained more severe injuries that would have warranted admission to an inpatient
rehabilitation program. There were no participants with uncomplicated mild injuries
included in this study. Screening evaluations to establish eligibility criteria for
randomization in the clinical trial were conducted no earlier than 9-months post injury.
Participants had to be > 18 years of age and live within a 100-mile radius of the
research center because of developmental issues impacting socialization and logistical
issues (e.g., transportation) for participants to attend study treatment sessions respectively
would have necessitated a separate methodology for younger individuals. Eligible
participants were also required to be residing in non-institutional settings, because such
settings allow for greater opportunities for social communication in various contexts.
Participants had to be fully oriented and no longer in a post-confusional state after injury,
COGNITION AND SOCIAL COMMUNICATION IN TBI
24
so that they could participate fully in treatment sessions. Evaluation instruments and
treatment were available in the English language only; therefore, participants who were
not fluent in English were excluded from participation in the study. Individuals with other
central nervous system diagnoses or severe psychiatric disorders (e.g., schizophrenia)
were excluded from participation. Additionally, persons with severe expressive and/or
receptive aphasia were excluded from participation, as such severe language difficulties
would limit the individual’s ability to participate in treatment. Although some eligible
participants may have been receiving rehabilitation services at the time of recruitment for
that study (9-months post-injury), such individuals were not excluded from participation
in the clinical trial. However, to ensure that such individuals were equally represented in
both arms of the clinical trial, randomization was conducted within two strata: those
receiving current treatment and those receiving no treatment.
With the IPR study, participants underwent a screening evaluation for the clinical
trial designed to identify individuals who were experiencing difficulties with one or more
communication behaviors. Demographic and injury-related information was also
collected. All participants with TBI meeting screening eligibility criteria that consented to
participate in the treatment study completed a baseline evaluation following the screening
evaluation and prior to randomization to treatment condition. Participants were asked to
complete questionnaires, tests, and interviews, including the measures used in the current
study.
Item Selection Process. Decisions about which items to retain for exploratory
factor analysis were based on review of the relevant literature and consultation with
COGNITION AND SOCIAL COMMUNICATION IN TBI
25
dissertation committee members who are experts in TBI research and measure
development. A summary of the item selection process can be found in Figure 1.
Measures
Demographic, pre-injury characteristics, & injury severity measures.
Participant information about demographics and injury severity was obtained from
patient interview and from the TBI Model Systems database. Data regarding age, sex,
race/ethnicity, years of education, injury severity, and time post-injury at assessment are
reported and were explored for use as covariates in planned analyses.
Neuropsychological measures. Neuropsychological measures of attention and
executive functioning were given to participants in the SCA study, including the Trail
Making Test, Controlled Oral Word Association, the Color-Word Interference subtests of
the Delis-Kaplan Executive Functioning Scale, and the Script Analysis Task. A brief
description of each of these measures follows.
The Trail Making Test (TMT; Army Individual Test Battery, 1944) was administered
as a test of visual attention and executive function. On the first trial (Trails A),
participants are presented with a page that has numbers on it and are instructed to draw a
line connecting the numbers, in sequence, while being timed. On the second trial (Trails
B), the examinee is given a sheet of paper that contains numbers and letters and asked to
draw a line alternating between numbers and letters in sequence while being timed. For
the current study, only the Trails B total time to completion was utilized, as this variable
is known to be sensitive to disruption in TBI patients (Spikman et al., 2000), and is also
predictive of social functioning (Struchen et al., 2008).
COGNITION AND SOCIAL COMMUNICATION IN TBI
26
During the Controlled Oral Word Association (COWA; Multilingual Aphasia
Examination, 1994), participants are presented with a letter of the alphabet (specifically,
letters F, A, and S) and asked to generate as many words as they can during a 60 second
time period. Participants are instructed not to respond with the proper names of people or
places, and are also instructed to not use the same word repeatedly with different endings.
The total number of valid responses that participants gave across the three trials was
utilized for these analyses. Total number of valid responses on the COWA has been
demonstrated to be sensitive to the effects of TBI (Spikman et al., 2000) and may be
related to social communication.
The Color-Word Interference Test of the Delis-Kaplan Executive Functioning Scale
(CWIT; Delis-Kaplan Executive Function Scale (D-KEFS), 2001) was administered as a
test of complex attention and executive function. There are four subtests that comprise
this measure. The third subtest, Inhibition, was selected for use in this study. During this
subtest, the participant is presented with color words that are printed in a different color
ink (i.e. the word RED may be printed in BLUE ink). The participant must name the ink
color and not read the word for each item as quickly as possible. The current study used
the total time to completion for the Inhibition subtest, as this score has been linked to
social and occupational functioning following TBI (Struchen et al., 2008).
The Script Analysis Measure (Sirigu et al., 1995) is an experimental measure
designed to test the participant’s ability to organize and plan out the steps for a complex,
non-routine task without the benefit of externally imposed structure. The examinee is
asked to plan a leisure trip to Mexico and instructed to write down all actions that would
be necessary to complete this task, starting when they began planning the trip and ending
COGNITION AND SOCIAL COMMUNICATION IN TBI
27
when they arrive in Mexico. Following the modified scoring procedure developed by
Struchen et al. (2007), scores derived from this measure include: total number of actions
generated, total time to complete the script generation, total number of errors, key
element errors, early closure errors, late closure errors, and mean importance rating for
key elements. For the current study, the mean key element importance rating score was
utilized, as this variable has been shown to be sensitive to disruption following TBI and is
predictive of social functioning outcomes (Struchen et al., 2007).
Emotion Perception Measures. The emotion perception measures utilized in the
SCA study included selected subtests from the Florida Affect Battery (FAB; Bowers et
al., 1991). For the proposed study, the Facial Affect Matching and Conflicting Emotional
Prosody subtests were selected. The Facial Affect Matching subtest requires the
participant to process the emotion being displayed during each item, and then select a
different face displaying the same emotional expression. The Conflicting Emotional
Prosody subtest requires the participant to correctly identify the emotional prosody of a
voice independent of the speaker’s content. The scores for each subtest are the number of
correct responses. Performance on these subtests has been demonstrated to be predictive
of social and occupational functioning in TBI patients (Struchen et al., 2008).
Social Communication Measures. Social communication measures included the
Profile of Pragmatic Impairment in Communication, the TIRR TBI Social
Communication Rating Form, and the Assessment of Interpersonal Problem Solving
Skills. Information on the basic structure and construction of the Profile of Pragmatic
Impairment in Communication (Linscott, Knight, & Godfrey, 1996) is discussed in detail
in chapter 1. For the current study, the PPIC was used to rate an unstructured
COGNITION AND SOCIAL COMMUNICATION IN TBI
28
conversation between a research confederate and a participant. Research confederates
were provided with minimal instruction, and were told to converse with participants as
though they were meeting them for the first time (which they usually were) in a
community setting. Research confederates introduced the task to participants as a “getting
to know you” conversation, telling participants that they would find out information
about the participant, and that the participant should find out some information about
them. The 10-15 minute conversation that followed was video recorded and reviewed by
raters using the PPIC at a later date.
The TIRR Social Communication Rating Form was originally designed as an attempt
to simplify the measurement of communication difficulties in TBI patients during a
conversational discourse sample. It consists of 17 behavioral items, and it includes items
such as “Transitions between conversation topics made by the individual were smooth,”
and “Conversational topics were appropriate given the context.” A complete copy of the
measure can be found in Appendix C. Each item is rated by a trained researcher after
watching a video-taped unstructured conversation between a participant and research
confederate using a 5-point Likert scale ranging from 0 (not applicable, opportunity not
present) to 4 (Most of the time or always). Three of the items are reverse coded. The
researcher also rates the participants overall appropriateness of social communication
skills using the same 5-point Likert scale. The mean of the 17 behavioral items is then
calculated to create the Total Average Item Score, with higher scores indicating greater
social communication skill. This measure was initially created as a more parsimonious
and user-friendly alternative to the PPIC. However, it has not yet been empirically
COGNITION AND SOCIAL COMMUNICATION IN TBI
29
validated, and was included in this study as a preliminary attempt to investigate its utility
as a measure of post-TBI communication impairments.
The Assessment of Interpersonal Problem Solving Skills (AIPSS; Donahoe et al.,
1990) is a measure which involves showing the participant a videotaped vignette of
actors involved in either neutral or problematic social situations. The participant must
determine whether or not the scene depicts a problematic social situation (Identification
Score, 0-1 points), and if so describe the problem involved (Description Score, 0-2
points). The participant is asked to describe how they would respond in the depicted
situation (Processing Score, 0-2 points). The participant is then asked to role-play the
delivery of a response as the primary character in the vignette (Sending Skills) The
participant’s performance is scored separately for the verbal content (Content Score, 0-2)
of their response (disregarding any non-verbal or para-verbal behaviors) and their non-
verbal or para-verbal behaviors (Performance Score, 0-2 points) . The participant also
receives an Overall Sending Score, which takes into account the overall effectiveness of
the content of their message and their non-verbal/para-verbal behaviors. A copy of these
scoring guidelines is included in Appendix C. The current study utilized the participant’s
Overall Sending Score, which involves rating linguistic and para-linguistic aspects of the
participant’s response based on whether it was likely to achieve the desired outcome and
the extent to which the response was appropriate to context and presented in a polished
manner. There are five possible scores that can be obtained for the Overall Sending
Score, ranging from 0 to 2 points. Higher scores are indicative of more appropriate and
effective responses. The AIPSS overall sending score was included to measure another
aspect of the participant’s expressive communication ability.
COGNITION AND SOCIAL COMMUNICATION IN TBI
30
Statistical Analyses
Specific aim 1.
Hypothesis 1a. An exploratory factor analysis was conducted on the 20 selected
PPIC items using the principal axis factoring technique in SPSS(24). Prior to conducting
factor analysis, the suitability of the data for factor analysis was assessed. A correlation
matrix containing each of the 20 selected items from the PPIC was created and inspected.
The Kaiser-Meyer-Olkin value was also calculated in order to examine the level of
diffusion or compactness in the pattern of correlations between items. Following
guidelines established by Kaiser (1974), a KMO value below 0.5 indicates a high level of
diffusion in the pattern of correlations, and would result in a re-examination of items to
be included in the factor analysis. Following guidelines set by Hutcheson & Sofroniou
(1999), KMO values between 0.5 and 0.7 were considered mediocre, values between 0.7
and 0.8 were considered to be good, values between 0.8 and 0.9 were considered to be
excellent, and values greater than 0.9 were considered to be superb. The Bartlett’s Test of
Sphericity was also conducted in order to determine whether the correlation matrix was
significantly different from an identity matrix. If the Bartlett’s Test of Sphericity reaches
statistical significance, this would provide further support for the factorability of the
correlation matrix. There are theoretical grounds suggesting that the factors comprised of
the 20 items are significantly correlated, so oblique rotation using the promax method in
SPSS was utilized for this analysis. The decision of how many factors to retain was based
on the number of factors with eigenvalues greater than one and examination of the
resultant scree plot. The resultant factors were then examined for internal consistency by
COGNITION AND SOCIAL COMMUNICATION IN TBI
31
calculating Cronbach’s α for each factor. Values of 0.7 or greater were considered to
show adequate internal consistency for each factor.
Hypothesis 1b. Bivariate correlation coefficients were calculated between each
factor of the revised PPIC and CHART-SF Occupation subscale scores and CHART-SF
Social Integration subscale scores.
Hypothesis 1c. Bivariate correlation coefficients were calculated between each
factor of the revised PPIC,the TIRR Social Communication Rating Form total average
score, and AIPSS Overall Sending scores.
Specific Aim 2.
Hypotheses 2a-2c. ANCOVA models using hierarchical linear regression analyses
were created and tested for each of the four social communication measures. Given the
exploratory nature of this study, the decision was made to utilize an alpha level of .05
without correcting for multiple comparisons. The forced entry method was utilized for
each step in the analyses, and the variables in each step were selected based on theoretical
importance and results of previous research investigating cognition, social
communication, and social functioning in TBI patients (Struchen et al., 2008). Prior to
running these analyses, several assumptions of multiple linear regression were assessed.
The assumptions of multivariate normality were tested using the K-S test on the
standardized residuals to test whether they deviated significantly from normality. The
assumption of homoscedasticity was checked by inspecting a plot of residuals against
predictor variables. The assumption of independent errors was tested using the Durbin-
Watson test to test for serial correlations between errors.
COGNITION AND SOCIAL COMMUNICATION IN TBI
32
During each analysis, demographic variables (age and years of education) were
entered as the first group, followed by the injury-related variables (months post-injury
and ER GCS scores) as the second group, followed by the cognitive variables (TMT-B
time to completion, CWIT (Inhibition) time to completion, COWA total score, SAM
mean key element importance ratings, FAB Matching Facial Affect, and FAB Conflicting
Emotional Prosody) as the final group for predicting social communication performance.
It was anticipated that performance on TMT-B and FAB Matching Facial Affect would
emerge as significant individual predictors of performance on social communication
measures. These abilities are theoretically important for the social communication
process, and prior research has shown that both are sensitive to disruption after TBI
(Spikman et al., 2012; Struchen et al., 2008).
The degree of R2 change during each step of the regression was examined for
significance, and any variables that emerged as significant individual predictors were also
examined. The regression model was assessed for signs of collinearity by examining
variance inflation factors (VIFs), tolerances, and condition indexes. VIFs of 4 or greater
and tolerances of less than 0.2 were considered to be an indication of higher order
collinearity. Condition index values were also examined. Any value of 30 or greater was
considered to be indicative of possible multicollinearity. Furthermore, if two or more
variables related to a higher confidence index have high portions of variance explained,
concern was raised for multicollinearity among those variables.
COGNITION AND SOCIAL COMMUNICATION IN TBI
33
Chapter 3: Results
Sample Characteristics
Demographic and injury-related characteristics of the two samples (SCA
participants and IPR participants) are presented in Table 3. The majority of sample
participants were men, as is often the case in TBI research studies (Langlois et al., 2006).
Comparisons of demographic characteristics between the two study samples were made
using independent t-tests and chi-square tests. There were significant differences in the
proportions of ethnicities represented in each sample (specifically for white, black, and
Hispanic/Latino participants) [χ2 (2) = 15.82; p < .01]. The IPR study sample contained a
greater proportion of black and Hispanic/Latino participants compared to the SCA study
sample. This was likely due to the inclusion of a county-funded inpatient rehabilitation
facility with a more ethnically diverse patient population as a recruitment site for the IPR
study. There were also statistically significant differences in the number of months post-
injury between SCA and IPR participants [t (208) = 5.00, p < .01], with fewer months
since the injury for the IPR group. This difference in time since injury was the result of
inherent differences in study design and recruitment procedures between the SCA and
IPR studies. The two study samples were comparable with respect to gender proportions
and proportions of closed vs. penetrating injuries, as well as in mean age, mean years of
education, and mean ER GCS scores. Based on ER-GCS scores, the majority of
participants (71.5%) sustained a severe TBI, and the vast majority of participants (94.5%)
sustained a non-penetrating (i.e., closed) TBI.
Specific Aim 1: PPIC Development
COGNITION AND SOCIAL COMMUNICATION IN TBI
34
The 20 selected items from the PPIC were assessed for normality assumptions.
All of the item distributions were noted to be significantly non-normal based on
significance of the K-S statistic (p < .01) and examination of skewness, kurtosis, and
histograms. Most items were mildly to severely positively skewed. These items were
transformed to reduce skewness by taking the log of the raw scores. Following
transformation all PPIC item distributions remained significantly non-normal, so factor
analysis was conducted using the original item raw scores.
Data were missing for items 13 (3 cases), 14 (1 case) and 8 (59 cases). Many of
the missing values for item 8 (‘Perceived other’s misinterpretation of meaning’) resulted
from raters marking ‘not applicable’ for this item. Such ratings indicate that there was no
opportunity present for evaluating the participant’s perception of misunderstanding, most
likely because such misunderstandings are less likely to occur during such a short
conversational sample. Given the large amount of missing data for item 8, it was
excluded from all further analyses. The vast majority of data for items 13 and 14 were
present, and these items were therefore not excluded from further analyses.
The suitability of data for factor analysis was assessed. The Kaiser-Meyer-Olkin
value was .86, exceeding the recommended minimum value of .60 (Tabachnick & Fidell,
2001). The Bartlett’s Test of Sphericity was significant (p < .001), supporting the
factorability of the correlation matrix. The correlation matrix for the remaining 19 PPIC
items can be found in Table 4. Visual inspection of the initial correlation matrix was
notable for multiple high correlations (r > .80), and the determinant of the correlation
matrix was substantially lower than the conventional cut-off value of .00001 (Field,
2009). These findings were indicative of multicollinearity within the correlation matrix.
COGNITION AND SOCIAL COMMUNICATION IN TBI
35
Following an iterative process, the variables considered most likely to be contributing to
multicollinearity were systematically eliminated from the analysis. Through this
procedure, it was determined that items 4 (Contributes spontaneously to the
conversation), 12 (Elaborates spontaneously), and 14 (Integrates own ideas with other’s
ideas) were overly redundant with other items, and these were excluded from further
analyses. Upon examination of the anti-image matrix, item 7 (provides excessive detail)
was noted to have an unacceptably low individual KMO value (< .5), and it was excluded
from further analyses.
The remaining 15 items were subjected to principal axis factoring using
orthogonal varimax rotation. Comparison of results utilizing the transformed and raw
scores revealed very similar factor structures. Therefore, only the analysis of the raw
scores is reported in order to facilitate interpretation. The Kaiser-Guttman criterion of
eigenvalue greater than 1.00 was initially used to determine how many factors to extract.
Using this criteria and examination of the scree plot, two, three, and four-factor solutions
were obtained. Item 20 was found to have no loadings of .3 or greater on any factor, and
it was excluded from further analyses. The four-factor solution produced a poorly defined
loading matrix. Furthermore, examination of the scree plot indicated that two or three-
factor solutions were a better fit for the data. When the extraction of three factors was
specified, a relatively clean loading matrix was produced. However, items 11 and 17
were found to have no loadings of .3 or greater on any of the three factors and were
discarded from the analysis. Principal axis factoring with varimax rotation specifying the
extraction of 3 factors was conducted on the remaining 12 items, producing a clean factor
structure after rotation (Table 5). It was noted, however, that communalities for all three
COGNITION AND SOCIAL COMMUNICATION IN TBI
36
items within the third factor were relatively low compared to communalities of items in
the first two factors.
Reliability analysis was conducted for the items within each factor. The corrected
item-total correlations were all positive and ranged from .22 to .86. The coefficient alphas
for the first, second, and third factors were .93, .73, and .42, respectively, while the
coefficient alpha for all 12 items was .75. The coefficient alpha for the third factor was
below the recommended cutoff of .70 for social sciences research (Kline, 1999). Given
the relatively low communalities for items within the third factor, as well as the poor
reliability of this factor, the three items which comprised it (items 3, 16, and 18) were
excluded from further analysis. The factor analysis was repeated specifying only two
factors, producing a clean factor structure after rotation (Table 6). Reliability analysis for
items within the two remaining factors was repeated. The corrected item-total
correlations were all positive and ranged from .12 to .83. The coefficient alpha was .93
for the first factor (Partner Sensitivity), .73 for the second factor (Conversational Flow),
and .83 for all 9 items.
Factor scores of the participants were calculated for each of the identified factors
by the Regression method. Subscale scores were then created by summing the items
within each factor and, as statistically expected, correlations between factor scores and
the associated subscale scores were high (.99 for Partner Sensitivity and .96 for
Conversational Flow). Subscale scores were used in all further analyses for ease of
interpretation and generalizability. There was a trend toward statistical significance in the
correlation between Partner Sensitivity Scale and Conversational Flow Scale scores (rs =
.10, p = .07).
COGNITION AND SOCIAL COMMUNICATION IN TBI
37
Descriptive statistics for the Partner Sensitivity and Conversational Flow scales
can be found in Tables 7 and 8. Examination of the distribution of Partner Sensitivity
Scale scores revealed a bi-modal distribution in the overall sample, with the majority of
participants showing either minor difficulties or severe difficulties in partner sensitivity
behaviors. In contrast, Conversational Flow scores were severely positively skewed, as
the majority of participants showed little or no impairment in these behaviors.
Furthermore, no participant in this sample obtained the most severe (highest) score for
the Conversational Flow Scale, as the highest observed score was 10/12.
Differences in subscale performance among different demographic groups were
tested using independent samples t-tests and one-way ANOVA. There were no significant
differences between men and women for PPIC Partner Sensitivity scores [t (204) = -0.60,
p = .55] or PPIC Conversational Flow scores [t (208)= 0.66, p = .51]. Comparisons of
PPIC scores between participants of different ethnicities were conducted. Due to the
small number of participants who identified themselves as East Asian/Pacific Islander,
Central Asian, Native American, or other, these participants were combined into one
group designated as “Other.” There was no statistically significant effect of
race/ethnicity on PPIC Partner Sensitivity scores [F (3,202) = 1.75, p = .16] or PPIC
Conversational Flow scores [F (3,206) = 1.21, p = .31].
Criterion-related concurrent validity. Descriptive statistics for the PPIC subscale
scores and other measures of community integration and social communication are
presented in Table 7. Correlations between PPIC subscale scores and CHART-SF
Occupation and Social Integration subscale scores were examined in order to provide
preliminary evidence of criterion-related concurrent validity for the newly created PPIC
COGNITION AND SOCIAL COMMUNICATION IN TBI
38
subscales. Higher CHART-SF scores are indicative of better functioning, while lower
PPIC scores are indicative of better social communication abilities. It is important to note
that there were statistically significant differences in CHART-SF Occupation scores [t
(207) = 2.88, p < .01] and PPIC Partner Sensitivity scores [t (182.14) = -15.88, p < .01]
between the SCA and IPR participants, with SCA participants performing better on both
measures. There was a trend toward statistically significant better scores on the CHART-
SF Social Integration Scale for participants in the SCA sample compared to IPR
participants [t (188.65) = 1.87, p = .06].Conversational Flow Scale scores were not
statistically significantly different between the two samples [t (208) = -1.35, p = .18].
Due to the non-normal distribution of each of these variables, correlations were
calculated using a non-parametric statistic (Spearman’s rho).
Interpretations of the effect sizes of correlations were based upon guidelines set
by Cohen (1992), in which coefficients of .10 represent a small effect size, coefficients of
.30 represent a moderate effect size, and coefficients of .50 and higher represent a large
effect size. As described in the methods section, lower PPIC scores represent better
performance, while higher CHART-SF and AIPSS scores are indicative of better
performance. A small negative correlation was found between CHART-SF Occupational
scores and scores on the Partner Sensitivity Scale (rs=-.20, p < .01), indicating that lower
(better) partner sensitivity scores are associated with higher (better) Occupational Scores.
A moderate negative correlation was found between Occupational scores and the
Conversational Flow Scale (rs = -.36, p < .01), indicating that lower (better)
conversational flow scores are associated with better occupational scores. A moderate
negative relationship between CHART-SF Social Integration scores and Conversational
COGNITION AND SOCIAL COMMUNICATION IN TBI
39
Flow scores was found (rs = -.39, p < .01), indicating that better (lower) conversational
flow scores were associated with better (higher) social integration scores. There was no
significant correlation found between CHART-SF Social Integration and Partner
Sensitivity scores (rs = -.07, p = .16), or between PPIC subscale scores (rs = .10, p = .07).
A moderate positive correlation was found between CHART-SF subscale scores (rs = .45,
p < .01).
Convergent Construct Validity. Correlations between PPIC subscale scores,
TIRR Social Communication Rating Form scores, and AIPSS Overall Sending scores
were examined in order to provide preliminary evidence of convergent construct validity
for the newly created PPIC subscales. Higher TIRR Social Communication Rating Form
and AIPSS scores are indicative of better expressive communication, while lower PPIC
scores are indicative of better social communication ability.
There was a strong negative correlation between TIRR Social Communication
Rating Form scores and scores on the Partner Sensitivity Scale (rs = -.84, p < .01). There
was a moderate negative correlations between TIRR Social Communication Rating Form
scores and PPIC Conversational Flow Scale scores (rs = -.41, p < .01). There was a
moderate positive correlation between TIRR Social Communication Rating Form scores
and AIPSS Overall Sending scores (rs = .38, p < .01). Moderate negative correlations
were found between AIPSS Sending scores and scores on the Partner Sensitivity Scale (rs
= -.33, p < .01) and the Conversational Flow Scale (rs = -.43, p < .01), indicating that
lower (better) performance on PPIC subscales are associated with higher (better) AIPSS
Sending Scores.
COGNITION AND SOCIAL COMMUNICATION IN TBI
40
Specific Aim 2: Prediction of Social Communication Difficulties
All subsequent analyses were conducted using only data from participants in the
SCA study, as participants in the IPR study were not administered the cognitive measures
utilized in these analyses. Of note, the distribution of PPIC Conversational Flow scores
for SCA participants was similar to the distribution observed in the combined sample.
However, compared to the combined sample, the distribution of PPIC Partner Sensitivity
scores showed a less pronounced bi-modal distribution, with the majority of participants
scoring well on Partner Sensitivity items and a smaller group performing in the impaired
range. Based on examination of centered leverage values and Mahalanobis distances, two
cases were determined to be multivariate outliers and were excluded from all further
analyses. Descriptive data regarding performance on predictor and outcome measures are
presented in Table 8.
All variables were evaluated for assumptions associated with multivariate tests.
Distributions for all variables were assessed for normality by significance of the K-S
statistic, visual inspection of histograms and P-P plots, and assessment of skewness and
kurtosis values. According to significance of the K-S statistic, distributions for all
variables except the TIRR Social Communication Rating Form scores were significantly
non-normal (p < .05).Normality of skewness and kurtosis values for each variable was
assessed using guidelines described by Kim (2013), in which skewness and kurtosis
values are divided by their standard errors to obtain a Z score. The absolute value for the
Z scores is compared to the recommended cutoff of greater than 3.29 for a sample size
between 50 and 300. Using these guidelines, skewness values for all measures except the
COWA, TIRR Social Communication Rating Form, and AIPSS were non-normal (p <
COGNITION AND SOCIAL COMMUNICATION IN TBI
41
.05). Kutosis values for TMT-B, CWIT, SAM, Matching Facial Affect, and PPIC
Conversational Flow scores were non-normal (p < .05). Given the contradictory evidence
regarding the normality of COWA and AIPSS scores, histograms and P-P plots for these
variables were examined. Visual inspection of these histograms and P-P plots was
suggestive of slight departures from normality for the distributions of COWA and AIPSS
scores. Variable transformations were attempted to reduce skewness for both predictor
variables and outcome variables using square root, logarithmic, and inverse
transformations. These transformations were only successful in producing normal
distributions for a minority of the predictor variables and none of the outcome variables
at the cost of complicating interpretation of results. Therefore, variable transformations
were not utilized in the final analyses.
Histograms, P-P plots, and scatterplots of standardized residuals for each
regression model are presented in Appendix B. The assumptions of linearity and no
multicollinearity were met for all regression analyses. Other assumptions of linear
regression, including normality and homoscedasticity of residuals, were not met for
models predicting Partner Sensitivity scores, Conversational Flow scores, or TIRR Social
Communication Rating Form scores. However, these assumptions were met for the
regression model predicting AIPSS overall sending scores.
Descriptive Correlations. Descriptive correlations between predictor and outcome
variables are presented in Table 9. Statistically significant small to moderate correlations
were found between measures of affect perception and executive functioning, with better
performance on affect perception measures associated with better performance on
executive functioning measures. There was also a large correlation between the two
COGNITION AND SOCIAL COMMUNICATION IN TBI
42
affect perception variables, and moderate to large correlations between three of the four
executive functioning variables. Performance on the fourth measure of executive
functioning, the Script Analysis Measure, did not reach statistical significance with either
the other executive functioning measures or the affect perception measures. All social
communication outcome measures showed small to moderate correlations with years of
education. PPIC Partner Sensitivity scores were significantly associated with the COWA,
the CWIT, and the affect perception measures. PPIC Conversational Flow scores were
significantly associated time to completion on TMT B and the CWIT, as well as the
affect perception measures. TIRR Social Communication Rating Form scores were
significantly correlated with performance on the COWA, the CWIT, and Matching Facial
Affect. AIPSS Overall Sending scores were significantly correlated with performance on
TMT B, the COWA, the CWIT, and the affect perception measures.
Prediction of PPIC Partner Sensitivity Scale scores. Hierarchical multiple
regression analyses were conducted to determine whether the addition of injury-related
variables and then of cognitive variables improved the prediction of PPIC scale scores
over and above demographic variables alone. Results for the model predicting Partner
Sensitivity are presented in Table 10.In the first step, demographic variables accounted
for a significant amount of variance in PPIC Partner Sensitivity scores (R2 = .09, F (2,
98) = 4.86, p < .05). In the second step, injury-related variables did not explain a
significant additional amount of variance in the variance of Partner Sensitivity scores
after controlling the variance accounted for by demographic variables, though the overall
model remained statistically significant (R2 = .12, R
2 change = .03, F(4,96) = 3.39, p =
.01). In the final step, cognitive variables did not explain a significant additional amount
COGNITION AND SOCIAL COMMUNICATION IN TBI
43
of variance in the variance of Partner Sensitivity scores after controlling the variance
explained by both demographic and injury-related variables (R2 = .17, R
2 change = .05,
F(10, 90) = 1.90, p = .06). Examination of individual independent variables revealed that
years of education (β = -.23; t = -2.07, p < .05) was found to be a unique predictor of
Partner Sensitivity scores.
Prediction of PPIC Conversational Flow Scale scores. Results for the model
predicting Conversational Flow scores are presented in Table 11. In the first step,
demographic variables accounted for a significant amount of variance in Conversational
Flow scores (R2 = .10, F (2, 98) = 5.31, p = .01). In the second step, injury-related
variables did not explain a significant additional variance in the variance of
Conversational Flow scores after controlling the variance accounted for by demographic
variables, though the overall model remained statistically significant (R2 = .12, R
2 change
= .02, F(4,96) = 3.33, p = .01). In the final step, cognitive variables accounted for a
significant additional amount of variance in the variance of Conversational Flow scores
after controlling the variance explained by both demographic and injury-related variables
(R2 = .34, R
2 change = .22, F(10, 90) = 4.66, p < .001). Examination of individual
independent variables revealed that CWIT time to completion (β = .36; t = 3.48, p < .01)
and SAM Mean Key Element Importance ratings (β = -.20; t = -2.19, p < .05) were found
to be a unique predictor of Conversational Flow scores.
Prediction of TIRR Social Communication Rating Form scores. Hierarchical
multiple regression analyses were conducted to determine whether the addition of injury-
related variables and then of cognitive variables improved the prediction of TIRR Social
COGNITION AND SOCIAL COMMUNICATION IN TBI
44
Communication Rating Form scores over and above demographic variables alone.
Results are presented in Table 12.
In the first step, demographic variables accounted for a significant amount of
variance in TIRR Social Communication Rating Form scores (R2 = .17, F (2, 42) = 4.15,
p < .05). In the second step, injury-related variables did not explain a significant
additional variance in the variance of TIRR Social Communication Rating Form scores
after controlling the variance accounted for by demographic variables, though the overall
model showed a trend toward significance (R2 = .18, R
2 change = .01, F(4,40) = 2.13, p =
.10). In the final step, cognitive variables did not explain a significant additional amount
of variance in the variance of TIRR Social Communication Rating Form scores after
controlling the variance explained by both demographic and injury-related variables,
though the overall model again showed a trend toward significance (R2 = .37, R
2 change
= .20, F(10, 34) = 2.02, p = .06). Examination of individual independent variables
revealed that years of education (β = .38; t = 2.59, p < .05) was found to be a unique
predictor of TIRR Social Communication Rating Form scores.
Prediction of AIPSS Overall Sending scores. Hierarchical multiple regression
analyses were conducted to determine whether the addition of injury-related variables
and then of cognitive variables improved the prediction of AIPSS Overall Sending scores
over and above demographic variables alone. Results are presented in Table 13.
In the first step, demographic variables accounted for a significant amount of
variance in AIPSS scores (R2 = .12, F (2, 93) = 6.04, p < .01). In the second step, injury-
related variables did not explain a significant additional variance in the variance of
COGNITION AND SOCIAL COMMUNICATION IN TBI
45
AIPSS scores after controlling the variance accounted for by demographic variables,
though the overall model was statistically significant (R2
= .14, R2 change = .03, F(4,91)
= 3.70, p < .01). In the final step, cognitive variables accounted for a significant
additional amount of variance in the variance of AIPSS scores after controlling the
variance explained by both demographic and injury-related variables (R2 = .31, R
2 change
= .17, F(10, 85) = 3.82, p < .01). Examination of individual independent variables
revealed that Script Analysis Measure scores (β = .27; t = 2.78, p < .01) were found to be
unique predictors of AIPSS sending scores, and that years of education showed a trend
toward significance (β = .20; t = 1.88, p = .06).
COGNITION AND SOCIAL COMMUNICATION IN TBI
46
Chapter 4: Discussion
Specific Aim 1: PPIC Development
It was predicted that a factor analysis of the 20 PPIC items selected by research as
characteristic of social communication difficulties following TBI would yield a four-
factor solution similar to the factor structure of the LCQ, a self report measure of social
communication difficulties. This hypothesis was not supported by results of the current
study, as 11 of the original 20 items were systematically discarded from analyses due to
issues with missing data, multicollinearity, inadequate factor loadings, and inadequate
reliability. It is surprising that several of the items that were excluded due to inadequate
factor loadings and reliability contained conceptually associated content that was thought
to be related to disinhibition and impulsivity, one of the more common behavioral
disturbances found among the TBI population (Body et al., 1999; McDonald & Pearce,
1998). However, results of the current study indicate that these behaviors, or researcher’s
ratings of these behaviors, were not consistently and strongly correlated with one another
in this sample. Given the findings of previous research indicating that a subset of
individuals with TBI experience disruptions in social communication related to apparent
disinhibition and impulsivity (Hartley & Jensen, 1992), and taking into account the well-
documented heterogeneity of cognitive, behavioral, and social communication deficits
within the TBI population (Body et al., 1999), further investigation of these behavioral
items using a different sample is recommended.
The two factor solution that was eventually obtained accounted for 60.77% of the
total variance. This solution had a clean factor structure, characterized by relatively high
factor loadings, no significant double-loadings, and all items loading significantly on
COGNITION AND SOCIAL COMMUNICATION IN TBI
47
factors. Internal consistency for the two factors ranged from acceptable (α = .73) to
excellent (α = .93).
The items making up the first factor appear to consist of behaviors that would
facilitate dyadic interaction within a conversation. The phrasing of the items and
operational definition of the behaviors being rated is suggestive of a set of conversational
skills meant to enhance two-way communication within a conversation. These items are
also reflective of one’s awareness of and sensitivity to one’s conversational partner. In
contrast, items comprising the second factor appear to consist of behaviors that would
interfere with conversational interaction. The phrasing of these items and the
corresponding behaviors are suggestive of a set of expressive communication deficits
which degrade interactivity and interrupt the normal flow of a conversation.
The first of the two factors was labeled Partner Sensitivity, and it accounted for
40.99% of the total variance. The second factor was labeled Conversational Flow, and it
accounted for 19.78% of the total variance. Examination of the items comprising these
factors made conceptual sense, as the items within each factor appeared to pertain to
related aspects of social communication. These constructs also made sense from a clinical
perspective, identifying clusters of social communication difficulties which have been
documented in the TBI population (Linscott et al., 1996; Body et al., 1999; Hartley &
Jensen, 1992; Marsh & Knight, 1991; Chapman et al., 1992). Subscale scores were
created by summing item raw scores within each factor, and these subscale scores were
used in all further analyses.
COGNITION AND SOCIAL COMMUNICATION IN TBI
48
In order to provide preliminary evidence for the validity of the newly created
PPIC subscale scores, correlations between PPIC subscale scores and other measures of
community integration and social communication were examined. It was hypothesized
that PPIC subscale scores would be significantly correlated with CHART-SF Occupation
and Social Integration scores, as well as with AIPSS Overall Sending scores.
Conversational Flow Scale scores showed moderate correlations with CHART-SF scores
and AIPSS sending scores, with better Conversational Flow scores being associated with
better community integration and expressive communication. Partner Sensitivity Scale
scores were modestly correlated with CHART-SF Occupational scores and moderately
correlated with AIPSS sending scores, with better Partner Sensitivity scores being
associated with better occupational/productivity outcomes and better expressive
communication ability. However, there was no statistically significant correlation
between CHART-SF Social Integration scores and Partner Sensitivity scores.
These results provide preliminary evidence for criterion-related concurrent
validity and convergent construct validity for PPIC subscale scores, though evidence for
the criterion-related concurrent validity of Partner Sensitivity scores is somewhat
equivocal. Given the relationship between the subscale scores and measures of
community integration, the behaviors that comprise these factors may represent viable
targets for intervention and remediation in TBI patients with social communication
difficulties pending further investigation and validation.
Specific Aim 2: Prediction of Social Communication Difficulties
It was hypothesized that performance on measures of neurocognition
(specifically, attention and executive functioning) and social cognition (specifically,
COGNITION AND SOCIAL COMMUNICATION IN TBI
49
affect recognition) would significantly add to the prediction of social communication
ability as measured by PPIC subscales after accounting for the effects of demographic
and injury-related variables. Results of the current study partially support this hypothesis,
as performance on cognitive measures was related to certain aspects of social
communication. Specifically, performance on cognitive measures explained a significant
amount of variance in PPIC Conversational Flow scores and AIPSS Overall Sending
scores, both of which involve expressive social communication skills. For Conversational
Flow scores, CWIT time to completion and SAM mean key element importance scores
emerged as significant individual predictors. Better performance on these measures was
predictive of better Conversational Flow scores. The CWIT requires an individual to
process information quickly, selectively attend to certain aspects of a stimulus, and
inhibit an over-learned verbal response. The SAM requires an individual to organize and
formulate a plan for a complex task, and the score used in the current study (mean key
element importance scores) require the individual to make judgments about the
importance of each step in a complex behavioral sequence. Examination of the items that
comprise the PPIC Conversational Flow Scale (‘the flow of utterances is disrupted and
broken,’ ‘has a long response latency,’ ‘provides insufficient detail,’ and ‘has difficulty
naming objects’) provides the basis for a conceptual link between the complex
information processing speed, attention, and judgment skills required for these cognitive
tasks and the ability to express oneself without disruption during a conversation. This
idea has previously been discussed in the literature (Body et al., 1999; Hartley & Jensen,
1991; Marsh & Knight, 1991a), but findings are inconsistent and the relationship between
COGNITION AND SOCIAL COMMUNICATION IN TBI
50
measures of information processing speed, attention, and executive functioning and
conversational flow require further investigation.
For AIPSS Overall Sending scores, only the SAM mean key element importance
score emerged as a significant individual predictor. Better SAM scores were predictive of
better AIPSS Overall Sending scores. AIPSS Overall Sending scores are obtained by
asking the participant to role-play how they would respond in a situation in which there is
a social problem (i.e., if someone were to cut in front of them in a line). For the Overall
Sending score, the participant’s verbal response, as well as their para-verbal behaviors
(i.e., facial expressions, tone of voice, body language), are considered when rating the
quality of their response and the likelihood of achieving a satisfactory resolution to the
social problem. Similar to conversational flow skills, judgment and organization of one’s
thoughts are involved in formulating and expressing a verbal response within a social
context (McFall, 1982; Body et al., 1999; McDonald & Pearce, 1998). Furthermore, prior
studies have linked executive functioning deficits in participants with TBI to sub-optimal
request strategies in hypothetical social situations, which would support the involvement
of planning, judgment, and problem solving in an expressive communication task such as
the Sending portion of the AIPSS. Unlike expressive language skills in an unstructured
conversation, however, the individual completing the AIPSS is being asked to role-play
their response in a given social situation rather than to respond “in the moment” as part of
a dynamic conversation. This may allow participants more time to process and formulate
a response, which may explain why a measure of selective attention and information
processing speed (such as the CWIT) is not a significant individual predictor of AIPSS
COGNITION AND SOCIAL COMMUNICATION IN TBI
51
Overall Sending scores, while a measure involvement planning and judgment (such as the
SAM) is.
In contrast, performance on cognitive measures was not found to be predictive of
other aspects of social communication, such as the sensitivity of an individual to a
conversational partner. Cognitive variables, as a group, did not explain a significant
amount of variance in PPIC Partner Sensitivity Scale scores above that already accounted
for by demographic variables (age and education). There were similar findings for TIRR
Social Communication Rating Form scores. This is not surprising given the strong
correlation between TIRR Social Communication Rating Form scores and PPIC Partner
Sensitivity scores (rs = -.84, p < .01), which suggests that these two variables are actually
measuring very similar constructs. An unexpected finding was that only education
emerged as a significant individual predictor of PPIC Partner Sensitivity scores and TIRR
Social Communication Rating Form scores. More years of education were predictive of
better scores on both measures. It is possible that a relationship exists between education
and partner sensitivity behaviors, though it is impossible to determine causality based on
the current study results. One possible explanation is that individuals with higher levels
of education had better premorbid partner sensitivity skills, and that these individuals are
less vulnerable to social communication deficits following TBI. This “cognitive reserve
hypothesis” has been demonstrated with cognitive test performance in the TBI population
(Kesler, Adams, Blasey, & Bigler, 2003). It may also be that the significance of
education as a predictor of Partner Sensitivity scores and TIRR Social Communication
Rating Form scores is acting as a proxy for other variables that have not been accounted
COGNITION AND SOCIAL COMMUNICATION IN TBI
52
for in this study. Further investigation of the relationship between education and social
communication skills is needed.
As mentioned previously, these results support previous work which has explored
different communication deficit subtypes, or “profiles,” in TBI patients. One such profile
is characterized by failure to engage one’s conversational partner (Marsh & Knight,
1991b; Linscott et al., 1996). Descriptions of these individuals have much in common
with poor performance on items from the Partner Sensitivity Scale. Previous work has
generally not found significant relationships between traditional measures of cognitive
ability and this category of social skill deficit (Marsh & Knight, 1991b). This suggests
that traditional measures of cognition and social cognition do not adequately measure the
cognitive processes which underlie this aspect of social communication. One such social
cognitive process that may show a greater relationship to conversational partner
sensitivity behaviors is theory of mind. As discussed in the introduction section, theory of
mind requires an individual to maintain an awareness of another person’s potential
thought process in order to predict that person’s intentions. Given that research has found
that both theory of mind and partner sensitivity are affected in many individuals with TBI
(Muller et al., 2010; Spikman et al., 2012), the link between these abilities bears further
investigation. The complexity of social communication behaviors such as partner
sensitivity and the consistent failure to find a link between traditional cognitive measures
and these behaviors may also point to the effects of moderator variables as a bridge
between cognitive abilities and social communication. The external structure provided by
the examiner and the testing environment for most traditional neuropsychological
measures may mask underlying difficulties in the application of higher order cognitive
COGNITION AND SOCIAL COMMUNICATION IN TBI
53
processes that individuals with TBI may have in a less structured environment. Further
investigation of non-traditional measures of attention, executive functioning, and social
cognition (such as the Script Analysis Measure) and their relationships to traditional
cognitive measures and social communication may serve as a useful step towards
understanding social communication in the TBI population.
Study Limitations & Future Directions
There are a number of methodological and statistical limitations present in the
current study which may confound the interpretation and generalizability of these results.
The factor analysis of the PPIC and subsequent explorations of the relationships between
social communication, cognition, and demographic and injury-related characteristics was
conducted on a sample comprised solely of TBI patients. The absence of a control group
limits interpretation of these findings given the lack of available normative data regarding
the range of social communication ability in the general population. While it may be the
case that members of the general population are unlikely to display difficulties associated
with conversational flow behaviors (as was the case even within this TBI sample), it is
conceivable that there is a wider range of partner sensitivity behaviors within the normal
population. A related limitation regarding the measurement of social communication in
general, and the PPIC in particular, is that these tools often do not account for cross-
cultural social and conversational norms. Not only are there differences in typical or
acceptable conversational behavior across cultures, but individuals who identify
themselves as being members of a particular cultural/ethnic group may vary on their level
of acculturation within that group (Sue & Sue, 2015). These factors can complicate the
rating and interpretation of social communication behaviors for individuals who hold
COGNITION AND SOCIAL COMMUNICATION IN TBI
54
different cultural norms from the researcher or clinician using these tools. While no
statistically significant differences for Partner Sensitivity scores and Conversational
Flow scores were found between different ethnic groups in this study, the continued
investigation and consideration of cultural norms in the measurement of social
communication remains warranted.
Another limitation inherent to the measurement of social communication
behaviors with observational measures such as the PPIC is that conversational samples
are generally not recorded in vivo, but are arranged as “simulated interactions [in which]
an attempt is made to parallel real-life situations, and the subject and confederate are
given minimal instructions” (Marsh, 1999). Furthermore, participants are generally aware
that the conversation is being recorded and/or observed. In this regard, it is difficult to
know what ramifications observer effects may have on a participant’s social
communication behavior. It is also possible that social communication difficulties
following TBI may not manifest themselves in a single brief conversational interaction
except in more severe cases. The amount of missing data for the PPIC item ‘perceives
other’s misinterpretation of meaning’ due to ratings of ‘not applicable’ provides a prime
example. Except in the most obvious cases, this behavior is difficult to observe in a brief,
unstructured conversational sample unless it is explicitly elicited by the researcher.
However, difficulties in this area could have significant social consequences for
individuals with TBI. The use of self- and other-report measures such as the LCQ to rate
typically occurring social communication difficulties by the person with TBI and a
significant other may offer a useful comparison against those which are observed using
an observational measure like the PPIC. Another approach may involve observation of
COGNITION AND SOCIAL COMMUNICATION IN TBI
55
patient social interactions with clinicians and other patients within an inpatient
rehabilitation facility. This approach may circumvent the difficulties associated with
simulated conversational paradigms, while also providing valuable information to
clinicians and researchers about social communication proficiency in these TBI patients.
Other limitations of the current study include the marginal adequacy of the ratio
of predictor variables to sample size. While a sample size of 100 for 10 predictor
variables is conventionally considered to be an adequate ratio (10 to 1) by many
researchers, others argue that a ratio of 15 participants for each predictor is more
appropriate (Field, 2009). The use of an inadequate sample size in regression can result in
inadequate statistical power in some cases, therefore increasing the risk of making a type
II error. Similarly, while measures of sampling adequacy indicated a sufficient sample
size for factor analysis in the current study, many researchers advocate for a minimum
sample size of 300 in factor analytic studies (Tabachnick & Fidell, 2001). The ideal
solution in both cases would be to obtain a larger sample of TBI patients. However, given
practical limitations associated with obtaining large sample sizes for studies involving
TBI patients in the community, an alternative approach to the regression analyses may
involve including fewer predictor variables in the regression model. Examining
relationships between predictor variables and outcome variables prior to creating and
testing the regression models in an effort to select the most appropriate predictor
variables may result in a more parsimonious statistical model that simultaneously
preserves statistical power. Finally, the violation of several statistical assumptions
(normality of distributions, homoscedasticity of residuals) may have reduced the
statistical power of these analyses, obscuring potentially significant findings of the
COGNITION AND SOCIAL COMMUNICATION IN TBI
56
overall models or the unique contributions of individual predictor variables. Violation of
these statistical assumptions also limits the generalizability of these findings to the wider
TBI population.
Despite these limitations, the results of the current study represent an important
exploratory step in the investigation of social communication deficits and cognition in
TBI. Further research is needed to test the validity and generalizability of the two new
PPIC subscale scores, perhaps by using confirmatory factor analysis methods on a
different sample of TBI patients. Furthermore, while it may be difficult or even
impractical to develop a comprehensive set of norms for PPIC items and subscales
(particularly given the previously mentioned differences in cultural conversational
norms), future studies should include a non-TBI control group in order to test differences
between PPIC subscale scores in TBI vs. non-TBI individuals. As mentioned previously,
comparisons between self- and other-report measures of social communication (i.e., the
LCQ) and observational measures such as the PPIC may facilitate a more complete
understanding of social communication following TBI.
Conclusion
Despite several decades of research, the social communication difficulties
exhibited by individuals with TBI and the relationship between cognition, social
communication, and social functioning within this population are still poorly understood.
These constructs represent a complex interplay between various factors at multiple levels,
and the study of these relationships is further complicated by the difficulties in measuring
such complex and multifaceted behaviors in a standardized yet ecologically valid manner.
These issues highlight the need for development of accurate, reliable, and practical
COGNITION AND SOCIAL COMMUNICATION IN TBI
57
measures that can be utilized by both researchers and clinicians for the identification of
social communication difficulties in the TBI population. The development of such tools
facilitates greater understanding of the connection between neurocognition, social
cognition, and social communication, and may provide clinicians with viable treatment
targets for remediation of social difficulties following traumatic brain injury.
COGNITION AND SOCIAL COMMUNICATION IN TBI
58
APPENDICES
APPENDIX A Figures and Tables
Table 1
Hypothesized Factor Structure for Selected PPIC Items Initiation/Conversational Flow: Conversational Effectiveness:
The flow of utterances is disrupted and broken (dysfluency) Elaborates spontaneously
Has difficulty naming objects (anomic) Integrates own ideas with other’s ideas
Contributes spontaneously to the conversation Repeats information
Has a long response latency Partner Sensitivity:
There is good continuity between ideas Contributes equally to the conversation
Provides insufficient detail Helps direct the conversation
Disinhibition/Impulsivity: Perceives other’s misinterpretation of meaning
Talks about self too much (egocentric) Asks questions
Inappropriate (sexual, religious, political) content Gives appropriate types of listener responses
Provides excessive detail Is skilled at taking turns
Interrupts
Is overly intimate
COGNITION AND SOCIAL COMMUNICATION IN TBI
59
Table 2
Predictor and Outcome Variables for Specific Aim 2
Predictors
Outcome Measures
Demographic Variables
Age
Years of Education
Injury-Related Variables
Duration of time since injury (months)
Injury Severity (Emergency Room GCS Score)
Attention/Executive Functioning Measures:
Controlled Oral Word Association
Trail Making Test
DKEFS Color-Word Interference Test (Inhibition)
Script Analysis Task
Affect Perception Measures:
Florida Affect Battery (Matching Facial Affect, Conflicting Emotional Prosody)
Social Communication Measures:
Profile of Pragmatic Impairment in Communication Subscale Scores
TIRR TBI Social Communication Rating Form
Assessment of Interpersonal Problem Solving Skills-Sending Score
COGNITION AND SOCIAL COMMUNICATION IN TBI
60
Table 3
Comparison of demographic characteristics and key measures of the SCA and IPR participants
Total (N = 210) SCA Study (n = 116) IPR Study (n = 94) P
Race/Ethnicity, n (%)
White 135 (64.30) 88 (75.90) 47 (50.00)
< .01 Black 36 (17.10) 12 (10.30) 24 (25.50)
Hispanic/Latino 31 (14.80) 12 (10.30) 19 (20.20)
Other 8 (3.80) 4 (3.50) 4 (4.30)
Age mean (SD) [min-max]
36.70 (12.90) [18-75]
37.03 (11.83) [18 – 75]
36.30 (14.16) [18 – 71]
.69
Gender, n (%)
Male 146 (69.50) 79 (68.10) 67 (71.30) .62
Education in Years
mean (SD) [min-max] 13.14 (2.29) [6-20] 13.28 (2.39) [6-20] 12.96 (2.15) [8-19] .31
Months Post Injury
mean (SD) [min-max]
60.94 (49.73)
[10.00 – 289.80]
75.59 (46.75)
[12.60 – 289.80]
42.88 (47.52)
[10.00 – 219.70]
<.01
ER GCS Scores mean (SD) [min-max]
7.10 (4.12) [3-15]
6.68 (3.81) [3 – 15]
7.78 (4.53) [3-15]
.10
Initial Injury Severity Classification by
ER GCS Score, n (%)
Severe: 3-8 123 (71.50) 80 (68.90) 43 (66.20)
.29 Moderate: 9-12 17 (8.20) 11 (9.40) 6 (6.30)
Mild: 13-15 32 (15.30) 16 (13.80) 16 (17.00)
Injury Type, n (%)
Closed TBI 190 (94.50) 102 (93.60) 88 (95.70) .52
Penetrating TBI 11 (5.50) 7 (6.40) 4 (4.30)
ER GCS = Glasgow Coma Scale score upon admission to the emergency room
COGNITION AND SOCIAL COMMUNICATION IN TBI
61
Table 4
Correlations among PPIC items
Item 1 2 3 4 5 6 7 9 10 11 12 13 14 15 16 17 18 19
1 -
2 .42** -
3 .02 -.01 -
4 -.01 .15* .15* -
5 -.02 .17** .06 .75** -
6 -.02 .11 .25** .83** .77** -
7 .01 .08 -.09 -.01 -.08 .01 -
9 .40** .18** .09 .01 .18* -.03 -.25** -
10 .02 .23** .03 .82** .84** .76** .01 .02 -
11 .18** .01 .06 -.10 -.20** -.16** .16* .12* -.01 -
12 .03 .19** .10 .94** .76** .80** -.02 -.01 .85** -.12* -
13 -.01 .12 .23** .82** .79** .78** -.03 .05 .77** -.05 .79** -
14 .03 .24** .22** .81** .84** .82** -.06 .05 .81** -.14* .80** .83** -
15 .00 .07 .27** .82** .54** .66** -.00 -.03 .67** .01 .81** .72** .61** -
16 .00 -.18* .17** -.16* -.18** -.08 .05 .05 -.17** .20** -.15* -.13* -.15* -.11 -
17 -.08 -.10 -.05 -.06 -.10 -.10 .07 -.11 -.09 -.02 -.04 -.06 -.10 -.02 .29** -
18 .08 -.15* .20** -.23** -.35** -.13* .46** -.06 -.32** .28** -.28** -.21** -.29** -.14* .35** .20** -
19 .64** .31** .09 .02 .08 -.03 -.10 .44** .10 .08 .04 .05 .04 .07 -.02 -.05 .01 -
20 -.09 -.04 -.03 -.09 -.04 -.06 .21** -.06 -.13* -.06 -.12* -.08 -.08 -.10 .03 .14* .12* -.13*
N 210 210 210 210 210 210 210 210 210 210 210 206 209 210 210 210 210 210
Note. PPIC = Profile of Pragmatic Impairment in Communication.
* p < .05, **p < .01
COGNITION AND SOCIAL COMMUNICATION IN TBI
62
Table 5
Varimax rotated principal axis factoring loadings and communality estimates for PPIC
Item # Questionnaire item Factor I Factor II Factor III h2**
Factor I
13 Gives appropriate types of listener responses 0.91* 0.83
6 Contributes equally to the conversation 0.89 0.79
10 There is good continuity between ideas 0.87 0.84
5 Is skilled at taking turns 0.84 0.79
15 Helps direct the conversation 0.76 0.58
Factor II
1 The flow of utterances is disrupted and broken 0.83 0.69
19 Has a long response latency 0.79 0.62
9 Provides insufficient detail 0.51 0.26
2 Has difficulty naming objects (anomic) 0.45 0.25
Factor III
18 Talks about self too much (egocentric) 0.62 0.42
3 Asks questions 0.45 0.27
16 Is overly intimate 0.45 0.21
Percentage Variance (54.62%) 31.48 14.91 8.24
Note. *Boldface indicates significant primary loadings (≥.40) of items on each factor; **h2= communalities
COGNITION AND SOCIAL COMMUNICATION IN TBI
63
Table 6
Varimax rotated principal axis factoring loadings and communality estimates for PPIC
Item # Questionnaire item Factor I Factor II h2**
Partner Sensitivity
10 There is good continuity between ideas 0.90* 0.82
13 Gives appropriate types of listener responses 0.90 0.81
6 Contributes equally to the conversation 0.87 0.76
5 Is skilled at taking turns 0.87 0.76
15 Helps direct the conversation 0.73 0.53
Conversational Flow
1 The flow of utterances is disrupted and broken 0.83 0.69
19 Has a long response latency 0.79 0.62
9 Provides insufficient detail 0.51 0.26
2 Has difficulty naming objects (anomic) 0.44 0.21
Percentage Variance (60.77%) 40.99 19.78
Note. *Boldface indicates significant primary loadings (≥.40) of items on each factor; **h2= communalities
COGNITION AND SOCIAL COMMUNICATION IN TBI
64
Table 7
Descriptive statistics for social communication and community integration measures
Variable (range of possible scores)
N Mean (SD)
Median (IQR)
[min-max]
CHART-SF-Occupation Scale (0-100)
209 72.15 (33.06) 93 (44.5-100)
[0-100]
CHART-SF-Social Integration Scale (0-100)
210 86.16 (22.16) 100 (74.0-100)
[0-100]
PPIC Partner Sensitivity Scale (0-15)
206 7.91 (5.63)
9 (2-13)
[0-15]
PPIC Conversational Flow Scale (0-12)
210 1.43 (1.88)
1 (0-2)
[0-10]
TIRR Social Communication Rating Form Avg. Total Score (1-4)
49 3.20 (0.64)
3.35 (2.69-3.82)
[2-4]
Assessment of Interpersonal Problem Solving Skills- Overall Sending Scores % Correct (0-100)
107 62.07 (20.36) 66.7 (50-77.8)
[0-100]
Note. CHART-SF = Craig Handicap Assessment and Reporting Technique-Short Form PPIC = Profile of Pragmatic Impairment in Communication
COGNITION AND SOCIAL COMMUNICATION IN TBI
65
Table 8
Descriptive statistics for predictor and outcome measures for Specific Aim 2
Variable (range of possible scores)
N Mean (SD) [min-max] Skewness [Std. Error]
Kurtosis [Std. Error]
Trail Making Test Time to Completion Part B 109 92.63 (56.05) [32-346] 2.50 [0.23] 7.04 [0.46] Controlled Oral Word Association Total Words Generated 114 27.01 (12.57) [0-52] -0.55 [0.23] -.48 [0.45] Color-Word Interference Test Trial 3 (Inhibition) Time to Completion (0-180)
111 64.07 (20.98) [34-136] 1.48 [0.23] 2.37 [0.46]
Script Analysis Measure Mean Key Element Importance (0-5) 114 4.17 (1.12) [0-5] -2.55 [0.23] 6.78 [0.45] Matching Facial Affect Correct Responses (0-20)
114 16.70 (3.18) [3-20] -1.35 [0.23] 2.39 [0.45]
Conflicting Emotional Prosody Correct Responses (0-36)
114 28.52 (7.09) [11-36] -0.98 [0.23] -.21 [0.45]
PPIC Partner Sensitivity Scale (0-15) 111 4.17 (4.66) [0-15] 1.08 [0.23] -.22 [0.46] PPIC Conversational Flow Scale (0-12) 114 1.21 (1.92) [0-9] 2.20 [0.23] 5.27 [0.45] TIRR Social Communication Rating Form Average Total Score (1-4)
48 3.20 (0.65) [2-4] -0.46 [0.34] -1.17 [0.67]
AIPSS Overall Sending Scores % Correct (0-100) 107 62.27 (20.37) [0-100] -0.69 [0.24] .14 [0.47] Note. PPIC = Profile of Pragmatic Impairment in Communication
TIRR = Texas Institute of Rehabilitation and Research AIPSS = Assessment of Interpersonal Problem Solving Skills
COGNITION AND SOCIAL COMMUNICATION IN TBI
66
Table 9
Correlations among Predictor and Dependent Variables
Variable 1 2 3 4 5 6 7 8 9 10 11 12 13 14
1. Age -
2. Education .21* -
3. Months post-
injury .08 .06 -
4. ER GCS .23** .11 -.02 -
5. TMT B .32** -.21* .03 -.03 -
6. COWA -.03 .16* .06 -.08 -.32** -
7. CWIT .28** -.19* .22* -.04 .55** -.33** -
8. SAM -.17* -.06 .12 .04 -.04 .15 -.03 -
9. MFA -.25** .28** -.09 .01 -.42** .27** -.43** .06 -
10. CEP -.21* .35** -.02 -.07 -.62** .22** -.36** .08 .56** -
11. PPIC Partner -.04 -.36** -.01 .11 .11 -.20* .34** -.13 -.31** -.25** -
12. PPIC
Conversational Flow .13 -.16* .03 -.03 .28** -.14 .32** -.00 -.30** -.26** .28** -
13. TIRR SCRF .28* .37** .15 .11 -.14 .37** -.32* .17 .28* .14 -.84** -.41** -
14. AIPSS .01 .34** .01 .01 -.22* .17* -.21* .12 .36** .36** -.33** -.42** .38** -
N 114 114 114 105 109 114 111 114 114 114 111 114 48 105
Note. *p < .05, **p < .01; ER GCS = Emergency Room Glasgow Coma Scale score; TMT B = Trail Making Test Form B; COWA =
Controlled Oral Word Fluency Test; CWIT = Delis-Kaplan Executive Functioning Scales Color-Word Interference Test; SAM =
Script Analysis Measure; MFA = Florida Affect Battery Matching Facial Affect; CEP = Florida Affect Battery Conflicting Emotional
Prosody; PPIC = Profile of Pragmatic Impairment in Communication; TIRR SCRF = Texas Institute of Research and Rehabilitation
Social Communication Rating Form; AIPSS = Assessment of Interpersonal Problem Solving Skills
COGNITION AND SOCIAL COMMUNICATION IN TBI
67
Table 10
Prediction of PPIC Partner Sensitivity Scale scores Variable β t sr2 R R2 ΔR2
Step 1 .30 .09 .09*
Age .09 .87 .01
Education -.31 -3.12** .09
Step 2 .35 .12 .03
Age .03 .26 .00
Education -.33 -3.26** .10
Months post-injury -.02 -.16 .00
ER GCS .19 1.90 .03
Step 3 .42 .17 .05
Age -.08 -.64 .00
Education -.23 -2.07* .04
Months post-injury -.03 -.25 .00
ER GCS .21 2.01* .04
TMT-B Time -.03 -.21 .00
COWA Total Score .00 .04 .00
CWIT Inhibition Time .07 .57 .00
SAM Mean Key Element Importance -.10 -.93 .01
Facial Affect Matching -.13 -1.05 .01
Conflicting Emotional Prosody -.08 -.57 .00
Note. *p < .05, **p < .01; ER GCS = Emergency Room Glasgow Coma Scale score; TMT-
B = Trail Making Test Form B; COWA = Controlled Oral Word Association Test; CWIT =
Delis-Kaplan Executive Functioning Scales Color Word Interference Test; SAM = Script
Analysis Measure
COGNITION AND SOCIAL COMMUNICATION IN TBI
68
Table 11
Prediction of PPIC Conversational Flow Scale scores Variable β t sr2 R R2 ΔR2
Step 1 .31 .10 .10*
Age .24 2.39* .05
Education -.28 -2.79** .07
Step 2 .35 .12 .02
Age .25 2.38* .05
Education -.28 -2.81** .07
Months post-injury .14 1.50 .02
ER GCS -.05 -.53 .00
Step 3 .58 .34 .22**
Age .04 .35 .00
Education -.11 -1.13 .01
Months post-injury .08 .83 .01
ER GCS .01 .14 .00
TMT-B Time -.01 -.12 .00
COWA Total Score .04 .39 .00
CWIT Inhibition Time .36 3.48** .09
SAM Mean Key Element Importance -.20 -2.19* .04
Facial Affect Matching -.15 -1.33 .01
Conflicting Emotional Prosody -.05 -.37 .00
Note. *p < .05, **p < .01; ER GCS = Emergency Room Glasgow Coma Scale score; TMT-
B = Trail Making Test Form B; COWA = Controlled Oral Word Association Test; CWIT =
Delis-Kaplan Executive Functioning Scales Color Word Interference Test; SAM = Script
Analysis Measure
COGNITION AND SOCIAL COMMUNICATION IN TBI
69
Table 12
Prediction of TIRR Social Communication Rating Form scores Variable β t sr2 R R2 ΔR2
Step 1 .41 .17 .17*
Age .08 .52 .01
Education .38 2.59* .13
Step 2 .42 .18 .01
Age .09 .54 .01
Education .38 2.53* .13
Months post-injury .09 .64 .01
ER GCS -.04 -.28 .00
Step 3 .61 .37 .20
Age .21 1.28 .03
Education .22 1.39 .04
Months post-injury .14 .95 .02
ER GCS -.07 -.44 .04
TMT-B Time -.14 -.77 .01
COWA Total Score .23 1.47 .04
CWIT Inhibition Time -.21 -1.26 .03
SAM Mean Key Element Importance .15 1.04 .02
Facial Affect Matching .07 .40 .00
Conflicting Emotional Prosody -.11 -.57 .01
Note. *p < .05, **p < .01; ER GCS = Emergency Room Glasgow Coma Scale score; TMT-
B = Trail Making Test Form B; COWA = Controlled Oral Word Association Test; CWIT =
Delis-Kaplan Executive Functioning Scales Color Word Interference Test; SAM = Script
Analysis Measure
COGNITION AND SOCIAL COMMUNICATION IN TBI
70
Table 13
Prediction of AIPSS Overall Sending scores. Variable β t sr2 R R2 ΔR2
Step 1 .34 .12 .12**
Age -.12 -1.14 .01
Education .35 3.47** .11
Step 2 .37 .14 .03
Age -.10 -.89 .01
Education .36 3.56** .12
Months post-injury -.15 -1.58 .02
ER GCS -.04 -.42 .00
Step 3 .56 .31 .17**
Age .09 .83 .01
Education .20 1.88 .03
Months post-injury -.15 -1.56 .02
ER GCS -.09 -.86 .01
TMT-B Time -.05 -.44 .00
COWA Total Score -.08 -.78 .00
CWIT Inhibition Time -.09 -.78 .00
SAM Mean Key Element Importance .27 2.78** .06
Facial Affect Matching .15 1.24 .01
Conflicting Emotional Prosody .15 1.18 .01
Note. *p < .05, **p < .01; ER GCS = Emergency Room Glasgow Coma Scale score; TMT-
B = Trail Making Test Form B; COWA = Controlled Oral Word Association Test; CWIT =
Delis-Kaplan Executive Functioning Scales Color Word Interference Test; SAM = Script
Analysis Measure
COGNITION AND SOCIAL COMMUNICATION IN TBI
71
Initial item pool:
84 items
Reduced item set:
24 items
Literature review,
clinical & research
experience to inform
initial item selection
Items for use in
exploratory factor
analysis:
20 items
Group discussion with
committee members
to eliminate
redundant items
Use of LCQ factors to
inform factor analysis
hypotheses
Figure 1. Initial item selection process for the Profile of
Pragmatic Impairment in Communication.
COGNITION AND SOCIAL COMMUNICATION IN TBI
72
APPENDIX B Distribution Histograms, P-P Plots, and Scatterplots
Partner Sensitivity Regression Residual
Plots
Conversational Flow Regression Residual
Plots
COGNITION AND SOCIAL COMMUNICATION IN TBI
73
TIRR Social Communication Rating Form
Regression Plots
AIPSS Regression Plots
COGNITION AND SOCIAL COMMUNICATION IN TBI
74
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