Single-Subject Designs and the Field

of DeafblindnessAmy T. Parker, M.S.S.W.

Roseanna Davidson, Ed.D.Devender Banda, Ph.D., BCBA

Texas Tech University

Sociopolitical Context for this Study

NCLB What Works Clearinghouse (WWC) Response from the CEC, APA and others

Experimental Research in Education Tawney and Gast (1984) refer to the

“missing era of empiricism” in the broader development of field of special education. They further describe the development of the special education system as one created by external political forces that led to a rapid need for teacher preparation training programs at colleges and universities.

Development of the field of deafblindness Within the development of the field of

deafblindness in the United States, the 1964-65 rubella epidemic, which preceded Public Law 94-142, and created an immediate need for practitioners and educators across all service systems to meet the diverse needs of a population of deafblind children unlike any that had been served in U.S. educational service systems in the past (Enerstvedt, 1996; Spar, 1972).

Rationale for the Study A heterogeneous population Challenges of producing, replicating research with

low incidence population Uniqueness of the field on the cusp of

blindness, deafness and multiple disabilities Discovery of existing evidence for current

practitioners and families Platform for future research efforts

Research Questions: What types of single-subject design

studies, published in peer reviewed journals, were conducted with participants (adults and children) who are deafblind from 1965-2006 in the fields of education and rehabilitation?

Research Questions: What types of interventions and

educational practices were identified within these studies?

Are there any patterns of replication across studies that have been conducted?

Methodology published in peer reviewed journals included people who were deafblind as

participants (children or adults) focused on some type intervention or

teaching practice

Databases DB-LINK PsycINFO Academic Search Premier ERIC

Original Search Terms “deaf-blind studies”; “dual-sensory impairment studies” “research in deaf-blindness” “congenital rubella syndrome” “Usher syndrome” For DB-LINK the terms “study”, “research”,

and “design” were specifically applied to its database.

Inclusion/Exclusionary Criteria Studies that were correlational, empirically

descriptive, or qualitative were not considered in this examination. The fourth and final criterion for examining studies was that they employ single-subject design methodology and not some other type of non-randomized group designs.

Evaluation form A rating form was created based upon the

CEC’s quality indicators for single-subject design methodology and included the variables of: participant descriptions, settings, study design, independent variables, dependent variables, social validity and generalization.

Inter-rater Reliability The first and third author independently

rated 30% of the identified sample studies. Inter-rater agreement was calculated by dividing the number of agreements by the number of agreements plus disagreements and multiplying by 100. The inter-rater agreement was 100 %.

Additional search terms applied after study published Additional key author searches were applied post-

publication (Parker, Davidson & Banda, 2007). Ancestral searches of authors, continued

communication with DB LINK Librarians and discussions with field leaders have lead finding additional articles.

Hidden nature of deafblindness as a disability within the literature.

Types of Studies That Emerged Behavior: n=28 Communication: n= 23 Daily Living Skills: n= 21 Vocational: n=5 Total Participants = 143;

Age range 8 months- 38 yrs.

ages 0-10age 11-2122 +

Categories Within Behavior n = 28Published range 1969-1998

Self-injurious behavior studies n = 14

Participant Age Range: 5-25 yrs; M = 15.14 yrs.

Total part. = 22

Aggressive behavior studies: n = 6

Participant Age Range:

6-25 yrs; M = 14 yrs.

Total part. = 7

Non-compliant behavior

Studies: n = 8

Participant Age Range:

6-25 yrs.; M = 14.86 yrs.

Total part. = 8

Settings for Behavioral Studies Residential Schools

for the Blind/Deaf = 9 Self-contained

classrooms = 8 ICFMR = 6 Group home = 3 Workshop = 3 Supported living = 1 Training event = 1

SC ClassRSB/DICFMRGrp. Hm.WkshopOther

Types of Behavioral Interventions: Based on Least Restrictive Model (Mori & Masters, 1980)

Least Intrusive Interventions- n = 24

FCT; NCR; CR (food, praise); DRO, DRI, DRA, DRL; Token economy

More Intrusive- n = 7 Response blocking, facial screening; spearmint scent in air; time-out

Most intrusive- n = 10 Temporary restraint of hands; helmet; splints; overcorrection; Rx

Aversive- n = 2 Water mist sprayed in the face

Frequencies of Intervention Types

DRO/I/A/LCR-fd/pr.Res/EquiNE TOFCTResp. B.H2O mst.face scr.scenttokenover cor.

Other considerations: Behavioral Twelve of the 27 studies conducted a FBA before

intervening. Ten of the 27 studies reported to offer training on

intervention procedures to teachers, staff, parents or consumers (self-management).

Twenty of the 27 reported adaptations for deafblind participants; the main adaptation was the use of sign language for communication access.

CEC Quality Indicator: Social Validity

While most of the studies included generalization measures, only one behavioral study formally measured social validity of the treatment. This study was also one of the few studies conducted in a community based setting (Umbreit, 1997).

Recommendations for Practice and Research from Behavioral Studies It is paramount to identify the variables that maintain self-

injurious, aggressive, or non-compliant behaviors through the application of functional behavior analysis.

Efforts of intervention, particularly for deafblind participants, should emphasize not only response reduction but skill acquisition (Luiselli, 1990). Aversive procedures by definition do not teach alternative behaviors (Luiselli, 1990).

There are literature gaps for identifying interventions for young children who are deafblind with behavioral challenges; research conducted in more inclusive settings; and the use of functional communication training for people who are deafblind to reduce severe behavioral problems.

Summary from Behavioral Studies and Future Questions: Twelve of the 27 studies used multiple components as a part of an

intervention package. Less intrusive interventions were partnered with more intrusive to reduce behaviors.

Thirteen of the 27 studies used less intrusive measures (DRO, CR, TE, FCT) alone to reduce severe behavior problems. A handful of studies used aversive or the most intrusive as the only approach.

More analysis is needed to measure what types of combinations were more effective.

Interventions should be replicated with measures of social validity and in less restrictive environments.

The field of applied behavioral analysis has evolved since 1960 (Horner et. al. 2002), these studies are a reflection of that evolution and of the history of people who are deafblind.

Communication Studies n = 231985-2006

Microswitch interventions

n = 7

Participants age range- 8 mos.- 32 yrs. M = 18 yrs.

Participants = 9

Multi-component Training

n = 10

Part. Age range- 3-35 yrs.

Participants = 30

Dual Communication Boards

N = 4

Part. Age Range- 16-20 yrs.

Participants = 15

Object Symbols; Prompting:

N= 2

Part. Age Range- 8; 21

Participants = 3

Analysis of Communication Forms & Functions by Intervention Types: Examples

Communication Interventions

Topographies of Communication

Behaviors

Communication Functions

Microswitch Interventions

Reaching; Leg movements,

Vocalizations, Head movements

Learn to request preferred object, person or action

Multi-component Partner training

Pointing, vocalize, reach, use words, signs, turn-taking,

initiating

Greeting, Request object, person or action, Comment,

Reject

Communication Studies Settings Residential Schools for

the Blind/Deaf = 5 ICFMR/Nursing = 3 Self-contained class = 4 Inclusive class = 3 Community employment =

5 Supported living = 1 Day Habilitation = 1 Child’s home = 1

RSB/DICFMRSC classI classEmploySLDHHome

Other considerations: Communication Sixteen of the 23 studies reported some

type of training on the intervention to other communication partners in the environment.

Nineteen of the 23 studies reported specific intervention adaptations for people who are deafblind (examples: tactile overlays on microswitch, object/tactile symbols; touch cues; and sign language).

CEC Quality Indicators: Generalization and Social Validity

Thirteen of the 23 studies included generalization measures.

Eight of the 23 formally measured social validity.

Recommendations for Practice and Research- Communication Studies Based upon replicated intervention within multi-component

intervention studies, there is evidence that intensive support and training for communication partners (peers, para-educators, residential support staff, teachers, parents) is supportive of building the expressive communication skills of deafblind people (multiple researchers, settings, locations; 30 participants)

Based upon replicated intervention, for some people with deafblindness, working with microswitches can provide a means for increasing requesting behaviors (multiple researchers, settings, locations, 9 participants)

Using preferred activities, objects, and people can assist in building meaningful communication exchanges. This was replicated across microswitch & multi-component studies.

Summary from Communication Studies and Future Questions: Assessment of replication of the IV is challenging. Using a microswitch to develop contingency awareness and

request preferred objects, people, or action was replicated with people who are deafblind with additional motor impairments.

Dual communication board studies (n = 4) represent true replication of the IV within a specific context and with people who have residual vision.

Multi-component partner studies share elements of replication in intensive support, training and feedback to communication partners. Each of these studies required partners to recognize and respond to unique topographies of communication (pointing, gesturing, orienting, using communication cards, signing, using words.) Thematically this was replicated as an intervention practice.

More analysis is needed to assess which combinations were most effective.

Daily Living Skills Studies n=211980-2004

Mobility & Physical Activity

n= 10

Participants Age Range: 14-36 y

Age M = 24.5 y

Part n= 16

Household Activities & Leisure Activities n = 5

Participants Age Range: 13-34 y

Age M = 20 y

Part n= 8

Self-feeding & Mealtime

n= 3

Participants Age Range: 6-18 y

Age M = 10 y

Part n= 6

Toileting

n= 3

Participants Age Range: 6-31 y

Age M = 15; Part n= 11

Settings for Daily Living Studies Thirteen of the 21 studies

occurred in institutional facilities.

Four of the 21 occurred in center schools.

Three occurred in residential schools for the blind

One occurred in a group home.

One occurred in a self-contained class in a typical school.

ICFMR

Center S

RSB

Gr.HomeSC Class

Other considerations for DLS: “Mobility & movement” considered

purposeful activities in the environment as a part of the study.

A wide varieties of assistive technology was used in 13 of the 21 studies (examples: robots, infared systems, lights, vibrating prompting devices, computerized systems, pants alerts)

CEC Quality Indicators: Generalization and Social Validity

Seven of the 21 measured social validity. Often this was measured through raters (parents & staff) viewing videotapes of interventions and considerations of “indices of happiness” for students.

Seven of the 21 measured generalization across behaviors or people.

Recommendations for Practice & Research from DLS

All of the movement and mobility studies were conducted with the same lead researcher. Replicate research with different research teams and in different settings to establish external validity.

Examine and replicate teaching components of other studies to establish practice.

Vocational Studies 1989-1998; n = 5 There were 8 participants, ages 13-38 yrs.

within this category. Lancioni et. al., 1991 used an alternating

treatment design to measure use of a vibratory prompting, contingent reinforcement and peer support in different combinations to improve on-task behavior during assembly work.

Lancioni et. al. 1992 compared use of a robot with contingent reinforcement under peer support and alone conditions in improving % of correct tasks in an assembly job.

Vocational Independent Variables One set of researchers used an alternating treatment design

to compare an adolescent’s work performance when he was trained with a peer supporter and when he was trained individually (Lancioni, Olivia, & Bartolini, 1990).

One set of researchers employed a withdrawal design to measure the use of tactile prompts and object cues across job tasks (Berg & Wacker, 1989).

In another study, modified alternating treatment design was used to compare choice-making in vocational assessment conditions with choice making in the actual work environment (Parsons, Reid, & Green, 1998)

Patterns in the Research All studies represented interventions utilized with

deafblind people who have additional disabilities (cognitive, developmental, orthopedic, etc.)

During the decade of 1986-1995, CRS was reported to account for about one third of the population of children and adults receiving education and rehabilitation services (Riggio, 1992). That proportion was directly represented in this research with a third of participants in the studies identified between 1986-1995 having CRS.

Limitations of This Study Breadth of age groups Limits of search terms- missing articles Hidden nature of people who are deafblind Breadth of practices made true analysis of

replication difficult Need for quantitative analysis of

components to determine more precise replications

Descriptors of people who are deafblind in the literature: examples “functional residual vision and deafness” “congenitally deaf with functional vision only

in one eye” “congenital cataracts with a hearing loss of

70 db” “deaf but had minimal vision” “multi-handicapped blind” “deaf and partially sighted”

Framework for measuring practice: Well-established (Lonigan, Elbert &

Johnson, 1998; Odom et. al., 2002) for SSD is when: n > 9 studies. (using CEC quality methodological practices for SSD)

Emerging & effective (Odom et. al., 2003) for SSD is when: n = 4-6 studies.

Probably efficacious (Lonigan et. al., 1998) for SSD is when: n > 3 studies.

More criteria for evidence-based practice: Is the practice operationally defined? Is the context clearly defined? Is the practice implemented with fidelity? Is the practice functionally related to change in

VALUED outcomes? Is experimental control documented across a

range of studies, researchers & participants? (n > 5 studies; > 3 researchers; > 3 geographic locales; > or = 20 participants)

Other Types of Experimental Designs That May Lend Support A small number of experimental studies found did

were not SSDs. The significance of these larger experimental

studies is that their findings support and contribute to the body of findings from the communication single-subject designs for use of object symbols, microcomputers, or assistive technology (Mar & Sail, 1994; Rowland & Schweigert, 2000; Schweigert & Rowland, 1992).

Implications for Future Research Line up the studies for like practices to examine

efficacy and true replication. Conduct quantitative analysis (PND) of replicated variables.

Build from past research to validate emerging practices.

Create new research based on other types of needs within the population (Usher, CVI with hearing impairment; CHARGE; others)

Create research with high levels of social validity by partnering with consumers and families.