Infant Motor Development and Home Envt

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INFANTMOTOR DEVELOPMENT AND THE HOME ENVIRONMENT

Andrea L AbbottSchool of ~ h ~ s i c a lherapy

Submitted in partial fulfilmentfor the requirements for the degree of

Master of Science

Faculty of Graduate StudiesThe University of Western Ontario

London, OntarioMay 1999

@AndreaAbbott 1999


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ABSTRACT

Forty-seven mother-infant dyads were recruited to study the relationship betweenthe home environment and infant motor development. When infants were 5 months old,each mother predicted her infant's motor development at 8 months, using the maternalversion of the Alberta Infant Motor Scale. At 8 months of age, aspects of the homeenvironment (measured by the HOME Inventory) and infant motor development(measured by the Alberta Infant Motor Scale)were assessed during a home visit.Although no statistically significant correlations were found between the specifiedrelationships. the study mothers in the sample had high expectations of 8-month motorperformance and both the mothers and the infants scored higher than normative sampleson aspects of the home environment and infant motor development. These findingssuggest that more supportive and stimulating home environments are associated withhigher infant motor development scores.

Keywords: infant motor development, home environment, parental expectations


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DEDICATION

I would like to dedicate this thesis to:My parents. Wendy and John Abbott, for their ongoing support, genuine interest in thisproject, and belief in my abilities.

My husband and friend, Ian Tate. I could not have completed this project without hisunwavering support and encouragement.

My daughter, Zoe, for providing the joy in my life.

And my baby-to-be, "Sam".


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ACKNOWLEDGEMENTS

i would like to thank the following people for their assistance with this project:

First and foremost, my advisor and mentor, Dr. Doreen Bartlett for her ongoing support.assistance, knowledge, expertise and friendship. She made this project a positive andrewarding experience.

My advisory committee. Dr. John Kramer and Jamie Fanning for their input.

The Public Health Nurses fiom the Middiesex Health Unit for welcoming me into theirclinics to recruit families.

The families that participated. I greatly enjoyed meeting such positive and welcomingmothers and babies.

The Physiotherapy Foundation of Canada for their financial assistance provided from theAnn Collins Whitmore Memorial Award.

The School of Physical Therapy, University of Western Ontario, for the financialassistance from the Special University Scholarship Fund.


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TABLE OF CONTENTS

.CERTIFICATE OF EXAMINATION............................................................................. 1 1.-.AE3STRACT .................................................................................................................. 111

DEDICATION ............................................................................................................... ivACKNOWLEGEMENTS ................................................................................................ v

...............................................................................................ABLE OF CONTENTS vi-..LIST OF TABLES ....................................................................................................... VIII

LIST OF APPENDICES ................................................................................................ ixLIST OF ABBREVIATIONS .......................................................................................... x

CHAPTER 1. INTRODUCTIONIntroduction....................................................................................................................... 1Related Research ............................................................................................................... 2

Relationship Between the Environment and Development ..................................... 2Summary ............................................................................................................... 6

Objectives ........................................................................................................................ -7Research Hypotheses.. ............................................................................................... 7CHAPTER 2. METHODSample and Design.. .......................................................................................................... 9Data Collection: Measures ................................................................................................. 10Data Collection: Procedures .............................................................................................. 13Data Analysis ................................................................................................................ 14


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CHAPTER 3 . RESULTSInitial Sample Characteristics ............................................................................................ 16

...................................................................................ample Characteristics at 5 Months I 7Sample Characteristics at 8 Months ................................................................................. ..20Results from ObjectivesPrimary 0bjectives ............................................................................................... -24

Secondary Objective ............................................................................................. -25

CHAPTER 4. DISCUSSIONDiscussion ...........................................Explanations for Negative Results .......

- ..............................................................................................linical Significance .. .. .. - 2 9Future Work ...................................................................................................................... 31................................................................................................ummary and Conclusions 3 2

REFERENCES ................................................................................................................ -34

APPENDICES .................................................................................................................. 37

VITA................................................................................................................................ -72

vi i


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LIST OF TABLES

TABLE PAGE

1 . Maternal Characteristics at the Time of Recruitment....... .... . : . . - . . . . - - ~ - ~ . - - - . . - - . .72. Summary of Mothers' Difficulty Completing the 5-Month

Fonns By Level of Education... .. -. - -. - - - - . .- . . . . . . . . - . . . - - . . . . 193 . Summary of Maternal Scoring of the Alberta Lnfant Motor

Scale Collected at 5-Months.. ................................................................... .. .- .- -- ..- -04. Summary of 8-Month Alberta Infant Motor Scale Scores.. . . . 225. Summary of Scores ?om the HOME Inventory

3Subscales I, IV, and V.................................... ........................................................ 23


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APPENDIX

LIST OF APPENDICES

PAGE. .Initial Questionnaire ............................................................................................... 37

Item Exam ples from the HOME Inventory ............................................................. 41Instructions and ltem Exa mples from the Maternal Version

o f the Alberta Infant Motor Scale .............................................................. -43Item Ex amples from the Alberta Infant Motor Scale .............................................. 46Summ ary of Data from Reliability Testing for the HOME

Inventory and the Alberta Infant Motor Scale ............................................. 48Ethics Approval ...................................................................................................... 50Letter o f Information .............................................................................................. 52Flyer ...................................................................................................................... 54Consent Form ......................................................................................................... 56

...........................................................................................-Month Questionnaire 58Extrapolated Norm ative Data Used to Convert 8-Month Alberta

Infant M oto r Scale Raw Data to Standardized 2-Sco res .............................. 62Summary of Da ta of Families Lost to Follow Up at the

5-Month M ail-out ....................................................................................... 64Score Ranges o f th e HOME Inventory ...................................................................66Summ ary Table for the Relationship Between Aspects of the Hom e

Environm ent and Infant Moto r Development ............................................... 68Summ ary Tab le for the Relationship Between Parental Expectations

and Infant Mo tor Development .................................................................... 70


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LIST OF ABBREVIATIONS

AIMS. ............................................................... -Alberta Infant Motor ScaleIQ ......................................................................... -..IntelligenceQuotientMAIMS ............................. --.MaternalVersion of the Alberta Infant Motor ScaIePDI ........................................................ Psychomotor Developmental IndexSES ........................................................................ Socioeconomic Stztus


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CHAIPTER 1INTRODUCTION

Introduction

A clear relationship between the home environment and intellectual developmenthas long been established (Bradley and Caldwell, 1976; b e y , Farren, and Campbell,1979; Parker, Greer, and Zuckerman, 198 8); however, the relationship between the homeenvironment and infant motor development is less evident. This can be explained partiallyby the belief that infant motor development evolves in the rate and sequence associatedwith maturation of the central nervous system (McGraw, 1945). This neuromaturationalperspective of infant motor development still forms the foundation for most therapeuticintervention programs for infants with motor dysfbnction. Recently, a new theoreticalframework based on dynamic systems theory has proposed an alternate way of explainingdevelopment, thus setting the stage for the exploration of new views of infant motordevelopment. The dynamic systems theory is a complex framework that has been used toexplain the processes of change in many physical, environmental, and psychosocialphenomena (Gleick, 1987). When applied to development, this theory suggests thatbehavior is self-organizing and that new behaviors arise spontaneously fiom the interactionof many changing subsystems based on the influential parameters in a task specificcontext. This research was not designed to test the complex processes of the acquisition ofnew motor abilities, but to examine one of the principle tenets: the contribution ofdifferent subsystems to infant motor development. Specifically,dynamic systems theorysuggests there are a host of subsystems within the child, and the physical and socialenvironments that contribute to infant motor development (Thelen, Kelso, and Fogel,1987). One of these subsystems might be the home environment and related influencessuch as parental expectations. Knowledge of the home environment might help toaccurately identify infants at environmental risk arid optimize treatment programs for


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infants and young children with motor delays. The present study was designed to clarifythe relationship between aspects of the home environment and infant motor development.

Related Research

As a result of the important shift in theoretical frameworks from theneuromaturational perspective to one incorporating principles of dynamic systems theory,a review of the motor development literature is warranted to answer the question "Does arelationship between the home environment and infmt motor development exist?".

Relationship Between the Environment and Development

The home environment is known to be associated with intellectual development. Ina longitudinal study, Elardo and colleagues (1975) found a correlation of -54between theHOME Inventory environmental assessment at 6 months and the intelligence quotient (IQ)at 36 months. Bradley and Caldwell(1977) also reported a significant correlation between6-month HOME Inventory scores and IQ at 3 years of age. Specifically, categorisation ofscores on the 6-month HOME Inventory resulted in correct identification of 71% of thechildren from the low IQ group at 36 months of age and 62% of the children from theaverage to superior IQ group at 36 months of age. Further evidence supporting therelationship between the home environment and intellectual development comes from astudy examining samples of low- and middle-income families. Ramey and colleaguesfound that the qualities of the home environment were different in a low socio-economicstatus (SES) home than in a middle SES home (Ramey, Farren, and Campbell, 1979). Theinvestigators reported that low SES mothers tended to be less verbal, interactive, andwarm towards their children. Rarney and colleagues have reported that between 50 to 60% of the variance in children's 36-month Standford-Binet Scores, which measuresintellectual abilities, could be accounted for by the mothers' attitudes, behaviour, andinteractions with their children.

When reviewing the literature examining the relationship between the home


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environment and infant motor development, evidence is less clear. Early researchconcluded that no relationship existed between these constructs (McGraw, 1935; Dennis,1938;Dennis and Dennis, 1940;Dennis and Najarian, 1957). In the early 193Os, infantmotor development was explained by the neuromaturational theoretical framework.Psychologists widely accepted the view that motor development unfolded in apredetermined time and sequence and was unaffected by the environment wazel, 1988).This fbndarnental assumption contributed to the climate permitting the deprivation studiesof McGraw (McGraw, 1935) and Dennis (Dennis, 1938). In their studies, two sets oftwins were deprived of stimulation in various ways. The premise was that these childrenwould be normal in all aspects of development with a Limited amount and range ofexperiences. The investigators' findings were reported in this fashion and appeared tosupport their views. In another study, Dennis and Najarian (1957) examined therelationship between effects of deprivation and infant motor development on infants whowere raised in a Lebanese institution. These infants were subjected to severe social andmotor deprivation resulting fiom lack of caregivers and swaddling practices, respectively.The investigators reported that although infants demonstrated highly significant delays attwo to twelve months of age, no long term developmental effects were observed at fourand a half o six years of age.

One example of an interpretation based on the neuromaturational model comesfiom a widely-reported historical study investigating the effect of infant cradling practicesof the Hopi people on the timing of independent walking (Dennis and Dennis, 1940). TheDennises found no difference in the age of walking between Hopi infants who routinelyused the cradle board in the first year and similar infants who did not. The investigatorsconcluded that no relationship between the use of cradle boards and the time of onset ofwalking existed, supporting their idea that motor development is unaffected by theenvironment. However, a plausible explanation of these results is that the deprivationperiod for the restricted infants occurred before the critical threshold for Hopi infants wasreached. On closer inspection of the description of cradle board use, it is clear that theywere used extensively for the first 3 months of the infants' lives and less kequentlythereafter. During this period, the infants had little or no opportunity for motor activity.


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After three months, these infants might have had sufficient experience with gross motoractivities because they were restricted for shorter periods of time. This alternateinterpretation of the Dennises' findings contrasts with their proposed idea that motordevelopment is unrelated to environmental influences.

Early evidence in support of the relationship between the home environment andinfant motor development comes fiom cultural studies. Cultural studies suggest thatvariability in the timing of motor development is present among infants growing up indifferent regions (Dennis and Dennis, 1940;Freedman, 1974; Super, 1976; Lester andBrazelton, 1981; Cintas 1988;Hopkins and Westra, 1988; Cintas 1995).

An example of this is the intracultural study by Hopkins and Westra (1988)investigating the environmental influences of matemal handling and parental expectationson infant motor development. The handling consisted of massage an d a repertoire ofactive and passive stretches performed by West Indian mothers. This routine was startedafter the mother and infant returned home from the hospital. Mothers continued toprovide passive stretches until the infant was too heavy to handle, which typicallyoccurred around the time of independent sitting. At 6 months, the investigators found thatthe infants whose mothers elected to implement the handling routine were more advancedthan the comparison group in the sitting descriptions of sits alone for a short time, can beleft sitting on the floor, and sits well in a chair. A larger proportion of the formal handlingregime infants stood when supported compared to the comparison group, however thisdifference only approached statistical sigdicance. Importantly, the mothers who did theformal handling routine had higher expectations for the skill of independent sitting andstanding than the mothers in the comparison group. The group of mothers providing theformal handling routine also scored significantly higher on the subgroups of provisionwith uppropriate [earning materials and maternal involvement of the HOME Inventory.This intracultural study demonstrates that variability of infant motor development existsand suggests that environmental factors may influence motor development.

Further evidence linking the environment and infant motor development isprovided by Fetters and Tronick (1996). These investigators reported that two low socio-economic status groups (infants exposed to cocaine in utero and controls) were more


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similar than different. Both groups scored poorly on general motor performance. At 4months of age, 91% of the exposed group and 78% of the control group scored poorlyenough to be considered for early intervention referral. These findings support theproposition that the environmental influence of poverty is associated with, and possibly astrong predictor of, motor developmental outcome.

Evidence against the sole influence ofneuromaturation is provided byDarrah andcolleagues (1998) in an investigation of the intra-individual rate of gross motordevelopment in full-term infants. The results suggest that the rate of motor developmentwithin individual infants is a non-stable process. Amean percentile change of 66.78percentile points (SD = 13 47percentiles) was found and 31 % of the infants scored lessthan the 10" percentile ranking on the Alberta M m t Motor Scale at least once during themonthly assessments fiom 2 weeks of age to the time of independent walking. Nosystematic pattern of variation among infants existed. These results question theassumption that infant motor development is consistentwithin infants, as suggested by theneuromaturational theoretical fiamework. Dynamic systems theory proposes that avariety of factors (including aspects of the environment) influence development andexplain the variability of intra-individual rates of infant motor development.

Further recent evidence supporting the influence of the environment is provided byMulligan and colleagues (1998). This study examined the relationship between variousphysical characteristics of child-care centres, including levels of interaction withcaregivers, access to a gross motor room, space per infant, and use of seats, swings andwalkers, and aspects of infant motor development including psychomotor development,activity levels, and body composition of the infants. The investigators found that the levelof interaction between infant and caregiver for infants of 12months of agewereassociated with infant motor development.A higher level of interaction was associatedwith lower infant psychomotor developmental scores. This inverse relationship might beexplained by the type of interactions that were occurring between the infant and caregiverin these centres. These centres tended to expose the infants to activities that encouragedthe infants to be calm and quiet, such as reading books and participating in fingerplaysongs. These results suggest that aspects of the hfknt 's environment do influence infant


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motor development, thus providing fbrther evidence that there are factors other thancentral nervous system maturation influencing infant motor development.

Summary

A detailed review of the English literature examining the relationship between thehome environment and infant motor development (Abbott and Bartlett, in press) yieldedevidence supporting a possible relationship between these constructs. Early studiessupported the view that the environment had no role in an infant's motor development.However, on re-examination of the data in the context of the theoretical framework at thetime of publication, a different picture emerges. The idea that motor development is morevariable and malleable than first thought comes fiom cultural studies. These studiesdemonstrate that parental expectations and cultural care-giving practices may haveimportant iduences on motor development. Studies examining the environmental factorof poverty and the associated qualities of the home environment contribute to the idea thatthe environment may have an influential role in motor development. Finally, clarification ofthe non-stable rate of motor skill acquisition within individual infants suggests that thereare more influences on infant motor development than central nervous system maturationalone. These sources of evidence support the dynamic systems theory in that multiplefactors influence infant motor development. Aspects of the home environment might actas one subsystem of these influential factors.

Further research is required to clarify the relationship between the homeenvironment and infant motor development before clinical strategies can be developed andimplemented. Specifically, aspects of the home environment and parental expectations ofmotor development need to be assessed and related to motor outcomes to determine ifenvironmental influences have an impact on motor development.


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Obiectives

The primary objectives o f the present study were:

1. T o determine the relationship between aspects of the hom e environment (HOMEInventory, Caldwell and Bradley, 1984) and infant m oto r development (Alberta InfantMo tor Scale (AIMS), iper and Darrah, 1994) at 8 months o f age.

2. T o determ ine th e relationship between parental expectations (th e maternal version o fthe Alberta Infant Mo tor Scale (MAIMS), Bartlett, 1992) o f subsequent infant moto rdevelopment predicted by the m others at 5 months and infant motor development(AIMS) assessed by a physical therapist at 8 months.

The seconda ry objective was:

1. T o explore the relationship between three subscales of the HOME Inventory(matenmi responsivity, provision of qproprzate learning materials, and maternalinvolvemenf)and th e Alberta Infant M otor Sca le pron e and standing subscales at 8months.

Research Hv~otheses

The primary hypotheses of the present study were:

1. There will b e a significant positive relationship b etween asp ec ts of the homeenvironment (as measured by three of theHOME Inventory subscales: maternal


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responsivity, provisio n of appropriate learning materials, and maternal involvement)and infant motor development (as measured by the AIMS) at 8 months of age.

2. There will be a significant positive relationship between paren tal expectations (asmeasured by th e MAIMS) at 5 months and infant m otor developmen t (as measured byth e AIMS) at 8 months.

Th e secondary hypothesis was:

1. There will be a si@cant positive relationship between th e HOME Inventory(specifically th e t hr ee subscales of maternal responsivity, provision ofappro priatelearning materials, and m u t e d nvolvement) an d the Alberta Infant M otor S caleprone and standing subscalesat 8 months.


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CHAPTER 2METHOD

Sample and Design

Sixty caregivers with infants aged 6 weeks to 5 months were targeted forrecruitment fiom three main sources: the London Middlesex Health Unit mother-babyprograms of Just Beginnings and the Well Baby Clinics; a program fbnded by HealthCanada, Healthy Mothers-Healthy Babies; and London Bridges Childcare Services.Recruitment f?om these sources was planned to obtain representation across the spectrumof socioeconomic levels. A sample size of 60 primary caregiver-infant dyads was chosento provide a power of .90 to detect a correlation greater than .40 (two-tailed alpha = -05)(Table 3 .3 .5 ; Cohen, 1988). A correlation of -40was chosen because it is the lowest valuein the range (-406 r 1 69)considered to reflect a "modest" correlation (Weber and Lamb,1970). This magnitude of correlation has been reported in the literature examining therelationship between the home environment and cognitive development (Carlson, 1985;Coll, 1986). Although these investigators reported non-significant findings for motoroutcomes (see Appendix A), the current study used a tool with greater ability to measurevariation in early motor performance. Using this detailed instrument, covariation betweenthe home environment and motor development is easier to detect.

Some exclusion criteria were relevant. OnlyEnglish-speaking caregivers wererecruited because part of the assessment process requires th e caregiver to answerquestions from the HOME Inventory (Caldwell and Bradley, 1984).Only those familieswho intended to care for their infant in the home for at least four days a week until thebaby was eight months old were considered. This arbitrary selection of greater than halftime was chosen in order for the home environment to have sufficient influence o n theinfant. No infants with known sensory, motor, and/or congenital disabilities were recruitedfor this study.


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A combination of a cross-sectional and a prospective correlationai research designwas used to examine the relationship between the home environment and infant motordevelopment. From a cross-sectional perspective, assessments measuring aspects of thehome environment (HOME Inventory) and the infant motor development (Alberta InfantMotor Scale, referred to as the A I M S ) were administered at a single occasion when theinfant was 8 months old. From a prospective correlational perspective, the maternalversion of the AIMS (referred to as the MAIMS) was mailed to the families when theinfant was 5 months old to determine the influence of parental expectations on infantmotor development at the age of 8 months.

Eight months of age was selected as th e assessment age for the HOME Inventoryand the AIMS because this has been reported to be the age at which the greatest amountof motor variability occurs. For example, at this age some infants are sitting while othersare walking. At 8 months of age the standard deviation of a group of typically developinginFants is 7.8 points on a 58 point scale (Piper and Darrah, 1994). By using 8 months asthe assessment age, motor variability is assured and the influence of chronological age onmotor development is controlled.

The independent variables in the present study were aspects of the homeenvironment and parental expectations of infant motor development. The dependentvariable was infant motor development.

Data Collection:Measures

Data collected from initial parental questionnaires (Appendix A) were used todescribe the sample. These data included: infant gender, birth weight, gestational age,parity, delivery complications, parental age, level of parental education, and ethnic origin.Research conducted in London indicates that the level of maternal education is anappropriate proxy for socioeconomic status among adults (Turner, 1994). Furthermore, itis an objective and reliably reported measurement.

The HOME Inventory (Caldwell and Bradley, 1984)was used (item examples arefound in Appendix B) to measure the independent variable of aspects of the home


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environment. This test consistsof 45 items divided into 6 subscales of re~pomivity,acceptance, organization, learning materials, involvement, and variety- For this study,only three of the six subscaleswere used: maternal responsivity, provision of appropriatelearning materials, and maternal involvement. Previous research indicates that these threesubscales may be more influential on infant development than the subscales o f acceptance,organization, and variety (Carlson et al., 1985;CoIl et al., 2986;Hopkins and Westra,1988). Scoring for each item is on a pass-fail basis; one point is acquired per pass item.Information needed for the test was obtained by interviewing the caregiver and observingthe interaction between parent and infant. The infant had to be present, alert, and happyfor the majority of the visit for this to be achieved. If he infant was unwell or unhappy,the assessment was rescheduled for another time.

The psychometric properties of the HOME Inventory have been investigated.Correlation coefficients reflecting internal consistency of the subscales are reported to be:.72 (maternal responsivify), -77@revision of appropriate Ieming rnaterzalr),and -69(maternal involvement) (Caldwell and Bradley, 1984). Interobserver reliability of 90%item agreement has been reported (Bradley and Caldwell, 1988). No test-retest reliabilityhas been determined because re-asking the i n t e ~ e wuestions a second time would createan artificial testing situation (Caldwell and Bradley, 1984). Face validity for the HOMEInventory exists; the questions developed for the assessment are based on a review ofenvironmental characteristics related to favorable developmental outcomes (Caldwell,1968). Over the last 15 years, the HOME Inventory has been revised and updated.Construct validity based on the correlation of the home environment and maternaleducation has been determined. The correlation coefficients between maternal educationand the subscales of m a t e d re~ponsivify,rovision of appropriate learningmaterials,and maternal involvement are reported to be .22, -31, and .31, respectively at th e age of 6months (Caldwell and Bradley, 1984). These low correlations provide someevidence forconstruct validity and also suggest that more than matemal education needs to beconsidered in assessing the environment.

To measure the independent variable of parental expectations, a spatiallyreorganized adaptation of the MAIMS (Bartlett, 1992)was used (instructions and item


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examples are found in Appendix C). The MAIMS was developed to allow mothers toassess their own infant's motor development. This was achieved by changing thecorresponding description of each developmental picture into lay-terms. Bartlett (1 992)reported the concurrent validity, in terms of intraclass correlation coefficients, betweenmothersy and physical therapists' assessment scores to be -99 or fill-term infants.

The MAIMS was spatially reorganized for the following reason. The originalversion had all four positions (lying on stomach, lying on back, sitting, and standing) oneach of 5 pages spaced according to the sequence in which the activities typically emerge.For example, at 6 months, the activities obtained by the ccaverage'ynfmt in the fourpositions fell in a relatively vertical he. The items were spatially reorganized such thatthe four positions were on a separate page. This format provided no cues to the parentregarding the activities the baby might be doing n relation to the four positions. Forexample, the parent rated the activities the baby was doing while lying on stomachindependently from the other three positions of lying on back, sitting, and standing.

To measure the dependent variable of infant motor development at 8 months ofage, the AIMS (Piper and Darrah, 1994) was used (item examples are found in AppendixD). This test is an observational, norm-referenced assessment designed to assess infantsfrom birth to independent wakingyup to the age of 18 months. The test is easilyadministered; no handling of the infant by the examiner and no special equipment arerequired. Each item within the four subscales (prone, supine, sitting, and standing) is ratedas "observed "or "not observed". A total score is tallied by adding all observed items an dall items below that of the least mature observed item. A percentile ranking can then bedetermined from the normative data. Reliability for the AIMS has been reported to behigh. Specifically, interrater reliability for a single testing occasion for the age range of 8to 11months is .98 and test-retest reliability is -99 (Piper and Darrah, 1994). Highconcurrent validity correlations were found when the A I M S was compared to the PeabodyDevelopmental Motor Scales (Folio and Fewell, 1983) (r = -94) and the psychomotorindex of The Bayley Scales of Infant Development (Bayley, 1969) (r = .85) or the 8 to 13month age range (Piper and Darrah, 1994).


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To achieve the secondary objective of exploring the relationship between threesubscales of the HOME Inventory and the A I M S , wo of the four subscales (prone andstanding) were used. The rationale for this is that there is greater variability in thesesubscales than either supine or sitting at 8 months of age.

Interrater reliability between the study investigator and advisor was conducted onthe AIMS and the 3 subscales of the HOME Inventory on the first 6 families recruited tothe project. The criterion of 90 % agreement on individual items for each subject wasestablished and met. Reliability was checked mid-way through the 8-month home visits.Again, the objective of achieving 90% item agreement was achieved. The study advisorhad previously established high reliability on the AIMS. A training videotape for theHOME Inventory was acquired and reviewed prior to reliability testing. Data fromreliability testing is found in AppendixE.

Data Collection: Procedures

Ethics approval was obtained &om the University of Western Ontario (AppendixF). Subsequently, caregivers attending the Just Beginnings and Healthy Mothers, HealthyBabies programs and Well Baby Clinics were informed about the study (first by theemployees of the various programs and clinics and then, if interested, by the investigator).Caregivers were provided with th e letter of information (Appendix G) o consider whetheror not they wished to participate in the study. Families using the London BridgesChildcare Services were informed about the study by means of a flyer (Appendix H) andletter of infomation. After consent had been obtained (Appendix I) an initialquestionnaire was given to participants to collect descriptive data about the sample. Whenthe infants were close to 5 months of age, the MAIMS was mailed to participants(AppendixC). Caregivers were asked to assess their infants' motor development at 5months of age and then to predict their infants' motor development at 8 months of age.Caregivers were asked to assess their infants' motor development at 5 months to permitanalysis of the contribution of 5-month motor status to the relationship between predictedand actual 8-month motor performance. At 8 months of age, a home visit was conducted.


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During this visit, 3 subscales of the HOME Inventory (Caldwell and Bradley, 1984) andthe A I M S (Piper and Dmah,1994) were administered. Also at this time, some additionalquestions were asked to check the health status of the infant and to collect fbrtherdescriptive data about the sample (Appendix J

To control for the potential bias of order effect of the testing (HOME Inventoryand AIMS), the order o f the measures for each caregiver-infant dyad was determined priorto the home visit. This was done by assigning odd identification numbers to receive theHOME Inventory first and the even identification numbers to receive the A I M S first.Some flexibility in this plan was required. For example, i ft he Xant was asleep on theinvestigator's arrival, the HOME Inventory was administered first because this was theinterview portion of the home visit. The AIMS was then administered when the infantwas awake and interested in his or her surroundings. Similarly, if the infant appeared to betiring during the interview process, the interview was interrupted in order to administerthe AIMS. The remaining HOME Inventory questions were then asked. Both the HOMEInventory and the AIMS can be administered with this degree of flexibility (Caldwell andBradley, 1984; Piper and Darrah, 1994). At the end of the home visit, feedback was givento each caregiver regarding the infant's gross motor development by discussing the AIMS.

Data Analvsis

All information gathered ffom the initial and 8-month questionnaires was analysedto describe the sample. The primary and secondary objectives were analysed bycalculating Pearson's r. The objectives were then analysed to take in account differences inchronological age because age and the effect of maturation is known to influence infantmotor development (Piper and Darrah, 1994). This was done by converting raw AIMSscores to standardised z-scores using extrapolated normative data (AppendixK). Theaverage change between 7 months and 8 months 3 weeks is 1.6 points on the AIMS(range 1-1-9) .

The raw scores were converted to z-scores to compare individual scores to thenormal curve distribution represented by the normative sample of the AIMS. A raw score


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is not always meaningfid by itself, however, knowing how a raw score compares in termsof standard deviations to a normative mean score is more meaningfid. For example, a rawAIMS score of 52 at 8 months means ittle; however, a z-score of + 2 indicates that theinfant's motor score is two standard deviations above the mean for infants 8 months ofage.

If normative data are available, z-scores can be calculated by dividing the deviationof the raw score from th e normative mean by the normative standard deviation using thefollowing equation (Glass and Hopkins, 1984):

where x = raw score, u = normative mean, and c = normative standard deviation.


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CWT E R 3RESULTS

Initial SampleCharacteristics

Forty-seven primary caregiver-infant dyads were recruited to participate in thisproject. More boys (n=28) than girls (n=19) were recruited. The average gestational ageof the infants was 39.6 weeks (SD = IS), with a range of 35 to 42 weeks. Two of theinfants were born prematurely, at 35 and 36 weeks' gestation. None of the caregiversreported any birth complications when considering their infant's wellbeing. At birth, theinfants weighed on average 3512grams (SD = 519), with a range of 22 15 to 4915 grams.Only two of the infants weighed less than 2500 grams; these two infants were born at 35and 37 weeks of gestational age.

All of the primary-caregivers of this sample identified themselves as the mother. Theaverage maternal age was 30.4years (SD= .9), with a range of 18 to 40 years. Only 2 ofthe mothers were under 21 years of age. Ninety-eight percent of the mothers identifiedthemselves as being Caucasian, with only one mother identifying herself as part Asian. Atthe time of recruitment, all mothers were caring for their infants in their homes hll-time, 7days of the week. A large percentage of the total sample indicated that they had completeduniversity (46.8 %), with only 6 mothers indicating that their highest level of educationwas partial or full high school completion. Sixty-three percent of the mothers were first-time parents. A summary of the maternal characteristics related to education and parity isfound in Table 1.


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Table 1. Maternal Characteristics at the Time of Recruitment.Characteristic

Education (n= 47)Some High SchoolCompleted High SchoolSome CollegeCompleted CollegeSome UniversityCompleted University

Additional Children at Home(n=46) *

0123

Frequency Percentage ( % )

I * Data not available for one family.

Sample Characteristics at 5 Months

At the time of the 5-month mailout, three families were lost to follow up. Thisoccurred for a variety of reasons (e-g. away for holiday, moving house, or providingincomplete data). No systematic differences in infant birth weight, gestational age, numberof other siblings, number of days cared for in the home by the mother and maternaleducation were noted between these three families lost to follow up and th e remainingsample. A summary table of these data can be found in Appendix L. The averagechronological age in months of the infants at the time the mothers completed the 5-monthforms ranged from 4.7 to 5.5, with a mean of 5.0 (SD = 0.2).

Upon examination of the returned assessments, inconsistencies in scoring were notedon 6 of the mothers' forms. Specifically, implausiblyhigh scores were observed in twocategories of explanation. First, some mothers assessed their infants as doing certain


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motor activities that were implausibly high compared to the normative values of theAlberta Infant Motor Scale (AIMS). For example, 100% of the normative sample failedto demonstrate the prone item of reciprocal creeping at 5 months of age. If a motherassessed her infmt as doing this activity, credit was not given to that infant for this item.Second, those mothers giving their infant credit for doing an item, but not giving credit fora prerequisite item, made it implausible that the infant was doing the more advanced motorskill at 5 months of age. En this case, the infants were not given credit for the moreadvanced item. For example, if the mother gave credit for the prone item reachingextended arm support but not for otrrpoint kneeling, then it was implausible that theinfant was doing this item at 5 months of age. The specific items that caused the concernthat these mothers had over estimated their infants' motor development included:proppedlying on side, reciprocal crawling. four-point kneeling to sittingor half-itting, andfour-point kneeling (2) from the prone sub-scale, sitting to lying from the sitting sub-scale (tocredit this item the infant needs to sit independently), and pulls to stand with support,pulls to stm&stands with support, and supported stunding with rotation from the standingsub-scale. The maternal assessment form did not specify that the infants need to attainstanding independently to gain credit for the standing items. Some of the mothersspecified on the forms that their infants were able to come to standing by pulling up ontheir forefingers. This description of 'pulls to stand' was not credited.

Some statistically significant differences were found between the 6 mothers who haddifficulties completing the maternal version of the AIMS (MAIMS) and the mothers whohad no difficulty completing the MAIMS. First, a significant differencewas found formaternal age ( ~ ( 43 ) 2.09, p < .04). The group having dficulty was younger than thegroup not having difficulty, with mean ages of 26.7 (SD = 5.5) and 30.4 (SD = 4.9),respectively. Second, a statistically significant difference was found for maternaleducation, (Fisher's Exact Test,g< 02). Because there were so few entries in the variouscategories of educational levels, the categories were combined into two groups: some highschool and completed high school became group 1, and the categories of some collegethrough to completed university became group 2. Fifty percent of the mothers in group 1had diEculty with the forms n contrast to only 8 .6 % of those in group 2. Table 2


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contains a summary of the mothers who had difficulty or no ditticulty completing theforms.

- - - -- ---Table 2. Summary of Mothers' Difliculty Completing the 5-Month Foms By Levelof Education.

A summary of the raw data collected fiom the 5-month maternal assessment of infantmotor development and prediction of infant motor development at 8 months is containedin Table 3 .

Diff~culyGroup 1.Some/completedhigh schooleducation (n = 6 ) .

Group 2 .Greater than highschool education(n = 38 ) .

No Difficulty

3

3

Percentage

3

35

50

8 .6


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Table 3. Summary of Maternal Scoring of the Alberta Infant Motor Scale Collectedat 5 Months.

MAIMS Subscale

Prone (mean, SD)

Supine (mean, SD)

Total (mean, SD)

Total (N = 44)

Raw Actual 5Month LMAIMSScores

Total (N = 44)

Raw Predicted 8Month MAIMSScores

Note: MAIMS = spatially reorganized adaptionInfant Motor Scale. SD= standard deviation. o f t h e maternal version of the A lberta

Sample Characteristics at 8 MonthsAt the time o f the 8-month home visit, one further family wa s lost to follow up.

The characteristics of this family include: infant birth w eight of 3990 grams, gestationalage of 40 weeks, maternal age o f 33 years, male infant gender, one other sibling in thehome, and a m aternal education level of 6 (com pleted university). In total, 43 hom e visitswere completed. T h e average chronological age o f the infants a t the time of the 8-monthhome visit ranged fro m 7 to 8-and-a- half months, with a mean o f 8.0months


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(SD = -3). Four infants fell outside of the targeted range of one week on either side ofeight months. Two of these infants were seven months and seven months and one week;this was due to corrections made for prematurity. Two of the infants assessed were 8-and-a-halfmonths; this was due to difficulties scheduling a time for the home visit.

At the time of the assessment, all of the mothers rated their infants' health to begenerally good and they reported that their infants were receiving routine health care.None of the mothers had concerns about their infants' hearing or visual abilities. Sixmothers mentioned that they were monitoring their infants for a pre-existing healthcondition or concern that they felt might influence their idants' overall development.These concerns included: size of head (n= 2), effects of prematurity, effects of a birthmark on the hand, low birth weight and low weight gain, and an ongoing bronchialcondition. None of the mothers considered any of these concerns to be presently affectingtheir infants' development. When questioned about their infmts' general mood, a I l of themothers considered their infants to be "usually cheefil and interested in what is going onaround himher". At the time of the 8-month home visit, 40 mothers reported that theywere at home with their infants for at least 4 out of 7 days a week. Seventy-four percentof the mothers were at home fbll-time with their infants. Three of the mothers hadreturned to hll-time work when their infants were six-and-a-half months old and werecared for out of the home for 5 days of the week.At the time of assessment,41 of the 43 infants were rated by the primaryinvestigator as "happy, content, and interested in their surroundings"; two infants wererated "somewhat unhappy, however, still interested in their surrounding^'^. All infantswere able to complete the assessment to determine scores on the AIMS and the HOMEInventory. After assessing each infant's motor development, all infants were judged to bedeveloping typically by the primary investigator.

A summary of the raw data collected at the 8-month home visit of infant motordevelopment and the three subscales of the HOME Inventory are surnmarised in Tables 4and 5, respectively. To take dserences in chronological age into account, all 8-monthAIMS scores were standardised using z-scores (see Appendix K for values to standardizeeach infant's score).


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Prone (mean, SD)

- - -- --Table 4. Summary of Raw &Month Alberta Infant Motor Scale Scores.AIMS Subscale

[ Note: SD = standard deviation.

Total (N = 43)

Supine (mean, SD)

Sitting (mean, SD)

Standing (mean, SD)

Total (mean, SD)

8.7 (0.7)

9.9 (1.4)

5.9 (2.6)

40.2 (7.8)


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Results from Obiectives

Primarv obiectives:

No statistically significant correlations (Pearson's r) were found between aspectsof the home environment, as measured by the HOME Inventory, and infant motordevelopment (using raw data and z-scores) for the following relationships: m a t e dresponsivity and the total AIMS score (g = -.13;g = -40 and r = -.14;g = -37,respectively); provision of appropriate learning materials and the total A I M S score (_r =-17;p = -27and r= 2 ;p = -17, respectively); maternal involvement and the total AIMSscore (1= -.04; p = -8 and _r = -.08; g = .63, respectively).

Scatter plots were constructed for each of the above relationships; no threshold ornon-linear relationships were apparent. Because the sample scored in the middle and upperranges of the HOME Inventory (see Appendix M), groups were recoded into 2 groups persubscale. All subscale scores from th e middle range were coded as group I and scoresfrom the upper range were coded as group 2. T-tests were then conducted to determine ifa difference in infant motor scores between the families that scored in the middle andupper ranges of the HOME Inventory existed. Although not statistically significant,families scoring higher on the subscale ofprovision of appropriate learning materials hadinfants with higher AIMS scores (g (41) = -1.96, p = -06). No difference in A I M S scoreswere noted for the subscales m a t e d equonsivity (g (41) = 1.34, p = -19) and maternalinvolvement (1(41) = - . 3 0 , p = -77).

No statistically sigmficant relationship was found between parental expectations at5 months and infant motor development at 8 months (using raw data and z-scores) asdetermined by Pearson's correlation coefficient (1= -19;p = -23 and r=19;e = -23,respectively). A scatter plot was constructed; no threshold or non-linear relationshipswere apparent. Due to the non-significant findings, the 5-month MAIMS data were notanalysed firther.


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Secondary Ob-iective:

No significant correlations (Pearson's r) were found between three subscales of theHOME Inventory and the raw scores for the prone and standing subscales of the AIMSfor the following relationships: m a t e d re~ponsivitynd the prone subscale(r = -.26;e = -09); m a t e r d respomzvity and the standing subscaie (1= -06;p = -7 ) ;provision of appropriate learning materials and the prone subscde (K = -21; = - 1 );provision of appropriate leaming materials and the standing subscale ( r = - 18;Q = -25 ) ;maternal involvement and the prone subscale (1= -.03; = -85); and maternalinvolvement and the standing subscale (z = 4 2 ; = -93). Scatter plots were constructedfor each of the above relationships; no threshold or non-linear relationships were apparent.


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those vaiues reported by the HOME Inventory (9.57 vs. 7.60; 7.91 vs, 5.04; 4.67 vs. 3.01,respectively). However, the variability of the study sample was consistently lower thanthat reported in the HOME Inventory (SD = 1.19 vs. 2.18; SD = 1.03 vs. 2.37; SD = 1.07vs. 1.59, respectively) emphasizing the homogeneity of the sample mothers (AppendixN).

Furthermore, related evidence supports the association between parentalexpectations and infant motor development. The study mothers had high expectations ofsubsequent motor development and their infants had high motor scores. This is evidentwhen comparing the predicted 8-month mean scores and the actual 8-month AIMS meanscores for the individual subscales and total score: prone 20.0 vs. 15.7, supine 9.0 vs. 8.7,sitting 11.6 vs. 9.9, standing 9.4 vs. 5.9, and total 50.0 vs. 40.2, respectively. Littlevariability existed among the mothers' expectations relative to the actual 8-month AIMSscores: prone 1.8 vs. 4.2, supine 0 vs. -73, sitting 0.7 vs. 1 4, standing 3-0 vs. 2.6, and 4.1vs. 7.8, respectively (Appendix0).s stated in Chapter 1, this study was not designed totest dynamic systems theory as it has been applied to motor development; however, theresults support the perspective that more than central nervous system maturation isassociated with variations in the rate of acquisition of motor abilities in infancy.

Explanations for Nepative Results

First, the study sample comprised a homogenous group of mothers. Specifically,little variability in ethnicity and maternal education existed among he families. Repeatedattempts were made to recruit a heterogeneous group of families from a variety of culturalbackgrounds and socioeconomic status (SES) levels. This was attempted by informingfamilies about the study through a variety of sources. Families participating in programstargeted to lower SES groups were spec5cally approached. None-the-less, the samplerepresented a homogenous group of Caucasian mothers (98 %) mainly from the middleand upper SES levels as determined by maternal education. In general, the study familiesprovided a stimulating and supportive home environment for their infants. No familiesscored in the lower quartile of the HOME Inventory for the subscales ofprovision ofqpropria te learning materials and maternal involvement, and only one family scored in


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the lower quartile for the subscale of maternal responsivity. This sampling bias, coupledwith a ceiling effect on the HOME Inventory scores, made it dEcult to detectrelationships between aspects of the home environment and infant motor development andparental expectations and infant motor development.

Second, the HOME Inventory provided little content to discriminate betweenmiddle and upper range of functioning families. The HOME Inventory was primarilydesigned to differentiate between inadequate and adequate home environmentsand not todistinguish between adequate and very supportive home environments (Bradley andCaIdweH, 1988). Because the samplemainly comprised adequate and very supportivehome environments, the HOME Inventory lacked sensitivity to detect a relationshipbetween aspects of the home environmentand infant motor development.

Third, the HOME Inventorywas designed to measure the quality of the homeenvironment to support cognitive, social, and emotional development (Bradley andCaldwell, 1988). Although the HOME Inventory has been used by a variety of healthprofessionals interested in various aspects of development, the HOME Inventory has notbeen validated to support infant motor development. Presently, no such measure exists.Afler an extensive search, the HOME Inventory was considered the best available measureto evaluate aspects of the home environment. Subsequent experience using the HOMEInventory clarified that the items selected to support infant cognitive development mightnot be the same as the items needed to support infant motor development. For example,the subscale ofprovision of appropriate learning materials combines items relating toequipment (i-e. strollers and high chairs) and toys that the infant plays with and has accessto. Equipment, in general, might not be expected to enhance motor development. Incontrast, toys might provide a motivating influence for infants to explore and learn abouttheir environment, thus supporting early motor development. If the equipment and toyitems were separated, a more appropriate grouping of items might exist. The subscaleprovision of appropriate learning ma terials might then assist in clarifying the relationshipbetween aspects of the home environment and infant motor development.

Fourth, Limitations associated with a univariate approach exist. Aspects of thehome environment measured may be necessary conditions supporting infant motor


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development, but i n su fFen t in absence of other interacting factors. This study was notdesigned investigate the multiple, interacting subsystems representing the entire physicaland social home environment.

Finally, limitations associated with a cross-sectional design exist. An assumptionthat the home environmentwill be stable over timewas made when using a cross-sectionaldesign to measure aspects of the home environment and idant motor development. Thesetwo constructs were simultaneously measured during the 8-month home visit. If the homeenvironment was measuredprior to assessing infant motor development, statisticallysignificant results supporting the relationship between aspects of the home environmentand infant motor development might have been detected. Alternatively, the homeenvironment could have been measured when the infmts were 8 months of age withfollow up for motor development occuring when the infants were between 10 to 12 monthsof age.

Although the targeted sample size of 60 mother-infant dyads was not achieved,sample size was not considered to be a limitation for this study because the 43 mother-infant dyads completing the study provide a power of -77 o detect a correlationcoefficient of -40 (Table 3 .3 .5 ; Cohen, 1988).

Ciinical Significance

Clarifying the relationship between aspects of the home environmentand infantmotor development has important implications for therapists working in the earlyintervention field. Specifically, if this relationship is confirmed, support will be providedfor early identification of infants at environmental risk, development of appropriateintervention strategies, consideration of the location for treatment, and decision-makingabout when to discharge infants Eom hr ther follow-up and treatment.

First, infants born with mild dyshnction who come from a disadvantagedbackground have been determined to be at greater risk than infants with more significantbirth insults who come from supportive and stimulating home environments (Parker,Greer, and Zuckerman, 1988). Therefore, infants at environmental risk need to be


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identified early to plan intervention strategies. Therapists might need to provide specificscreening services to determine which infants with motor dyshnction are at environmentalrisk.

Second, the development of appropriate intervention strategies might provideinfants at environmental risk with a stimuIating and supportive home environment. Ifrequired, further parenting education could be obtained by refemng the family to otherhealth professionals such as social work, parenting cIasses, and social assistance. Theearly intervention therapist, famiIy support services, and the family could work together toprovide an intervention program focusing on improving aspects of the home environment,thus supporting motor development.

Third, if therapists are to be effective in using resources available to the infant andfamily, an understanding of the physical and social home environment is necessary.Treatment in the home, instead of a clinic, would provide an opportunity for the therapistto incorporate meaningfbl activities using resources already available in the home. Itwould also enable the therapist to determine what other resources the family might need toprovide a supportive and stimulating home environment to enhance the infant's motordevelopment. If nappropriate suggestions are made with respect to parental expectationsand resources available to the family, there is Iittle chance the intentention will beeffective.

Fourth, before discharging an infant fiom therapy or follow-up, the homeenvironment should be taken into account. The home environment of the infant whodemonstrates borderline motor dyshnction shouid be considered when determiningpriorities for discharge. The infant identified at environmentalrisk may need prolongedtreatment and monitoring to ensure that progress continues and no fhrther movementconcerns anse.


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FutureWork

Before recommending implementation of the points suggested in the clinicalsignificance section (above), the relationship between aspects of the home environmentand infant motor development needs to be clarified fbrther in future investigations.

Because this area of research is observational, causality will be difficult todetermine. To strengthen the argument for a causal relationship between the homeenvironment and infant motor development, variations in study designs could beimplemented (Fletcher, Fletcher, and Wagner, 1996). These designs could include theelements o f temporality, strength of association., dose-response, reversibility, andconsistency. For example, to establish temporality between aspects of the homeenvironment and infant motor development, a prospective design could be implemented.The home environment could be assessed when the infant is between 3 and 5 months ofage. Follow-up assessment of infant motor development could then occur when the infantis between 8 and 12 months of age. To improve the prospective aspect of the studyexamining the relationship between parental expectations of motor development and infantmotor development, the time kame between predictions and actual assessment could bewidened. For example, mothers could predict their infant's subsequent motordevelopment before their infant is born. Follow-up assessment to measure actual 8-monthmotor development could occur when the infant is between 8 and 12 months of age.

The strength of association between the home environment and infant motordevelopment would be increased with implementation of the following suggestions into astudy design. First, replication of this study could be done with a sample comprising agreater representation of the full spectrum of SES across families. This could be achievedby working more closely with health professionals that are involved with families fromlower SES backgrounds. Second, a valid measure reflecting aspects of the homeenvironment that support infant motor development needs to be created. A fi st stepcould be identification of items within the HOME Inventory that reflect the relationshipbetween the home environment and infant motor development. By increasing thevariability of the sample and the sensitivity of the measure, detection of an association


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between the hom e environmen t and infant mo tor developm ent will be enhanced. Finally,the use o f non-linear analyses needs to be considered to examine the relationship betweenthe maternal subscales o f the HOME Inventory (maternal responszvzty, and maternalinvolvement) and infant mo tor development. Althoug h a non-linear relationship was notobserved on visual inspection of sca tter plots, such a relationship might exist in a sam plewith representation o f families fiom th e full spectrum of SES levels.

To determine i f a dose-response relationship exists, a heterogenous sample couldbe divided into the lo we r quartile and u pper 2~~ percentile on HOME Inventory. Theinfant motor d evelopm ent scores could then be compared. If infants fio m a moresupportive home environm ent had higher scores than infants fio m less supportive hom eenvironments, a dose-response relationship would be supported.

Support for a causal relationship between t he ho me environment and m otordevelopment might b e o btained by incorp orating the elem ent of "reversibility".Intervention could b e provided to vulnerable families throu gh social support and parentaleducation. If this elem ent exists, infant mo tor sc ores wou ld improve after interventionstrategies have been implemented.

Finally, con sistency o f results fiom different studies would strengthen the c ase fo ra causal relationship betwe en th e home environment and infant motor development. Forexample, recruitment fio m another ho mog enous gr ou p representing vulnerable familieswould provide furthe r evidence if this sample comprised low scoring groups fo r aspects o fthe home environment, parental expectations, and infant moto r development.

Summarv and Conclusions

This study aimed to clarify the relationship betwe en th e home environment andinfant motor dev elopme nt. Although no statistically significant correlations we re foundbetween aspects o f th e hom e environment and infant moto r development and parentalexpectations and infant m oto r development, the study sam ple comprised high scoringgroups for aspects of the h om e environment, parental expectations, and infant m oto r


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development. These findings sugg est that more supportive and stimulatinghomeenvironmentsare associated with advanced infant mo tor developm ent. The extent of thisrelationship needs fbrther investigation before therapeutic strategie s for early identificationand intervention can be designed and implemented.


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Bartlett D. Vaiidih;of M oth ers P ssessments of infant Motor Development. M. Sc .Thesis. Edmonton. AB: niversity o f Alberta, Department o f Physical Therapy;1992.

Bayley, N . Bqyley Sc de s of lttfanz Development. New York, NY: T he PsychologicalCorporation; 1969.

Bradley R, Caldwell B. Early home environment and changes in m ental testperform ance in children from 6 t o 36 months. Dev Psyrhol 1976; 2:93-97.

Bradley R, Caldwell B. Ho me ob servation for measurement o f the environm ent: avalidation st udy o f screen efficiency. Am JM e ~ z tDef 1977; 8 11417-420.

Bradley R,Caldwell B. Using the h om e inventory to assess the family environment.Pediatr Mrrs 1988; 14:97- 102.

Caldwell B. On designing supp lementary env ironments for early child development.BAEYC Reports 1968; 10:1-11.

Caldwell B, Bradley R. Home Observationfor Measurement of the Environment.Little Rock, AR: University of Arkansas; 1984.

Carlson D, Labarba R Sclafiani J, Bo we rs C. Cognitive and motor developmen t ininfants o f adolescent mothers: a longitudinal analysis. Int J Behav Dev l98S;g: 1-13.

Cintas H. Cross-cultural variations in infant mo tor development. Phys Occzrp TherPediatr l988;8(4): 1-20.

Cintas H. Cross-cultural similarities and differences in development and the impact ofparental expectations o n m oto r behaviour. Pediatr Phys 73er 1995;7:103-1 1 1.

Cohen J. Statistical Po wer Analysis for the Behavioral Sciences. Edition 2 . HillsdaleNY: ErIbaum; 1988.

Coll C. V o h r B, Hoffman J. O h W. Maternal and environmental fact ors affectingdevelopmen t ou tcome o f infants o f adolescent mothers. Dev andBehm Pediatr1986;7: 230-236.


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Darrah J, Redfern L, Maguire T, Beaulne P, Watt J. Intra-individual stability of rate ofgross motor development in full-term infants. Early Hzrm D rv 1998;52:169- 179.

Dennis W. Infant development under conditions of restricted practice and of minimumsocial stimulation: a preliminary report. J Genet Psycho[ 193 ; S S :149- 158.

Dennis W, Dennis M. The effect of cradling practices upon the onset of walking inHopi children. J Gene t PJychol 194O;56: 77-86.

Dennis W, Najarian P. Infant development under environmental handicap. P~). .cholMorzogr 1957;7l:1-13.

Elardo R, Bradley R, Caldwell. B. The relationship of infants' home environments tomental test performance from six to thirty -six months: a longitudinal analysis.Child Dev 1975;46:71-76.

Fetters L. Tronick E. Neurornotor development of cocaine-exposed and controlinfants from birth through 15 months: poor and poorer performance. Pediatrics1996;98:938-943.

Fletcher RH, Fletcher SW , Wagner EH. Clinical Epidemiology: The Essentials.Baltimore, MD: Williams and Wilkins; 1996.

Folio Fewell RR. Peabod y Developmental Motor Scales cnld Activity Cards.Chicago, IL:Riverside Publishing; 1983.

Freedman D. W a n nfmzcy: An Evolzrtionary Perspective. Hillsdale,N J : LawrenceErlbaum; 1974.

Glass G, Hop kins K. Statistical Methods irz Edzication and Psychology. EnglewoodCliffs, NJ: Prentice-Hall; 1984.

Gleick J . Chaos:MakrngaNcnv Science. New York, NY: Penguin; 1987.Hopkins B.Westra T. Maternal handling and motor development: an intracultural

study. Psychol M o~l ogr 988;114377-408.Lester B, Brazelton T. Cross-cultural assessment of neonatal behaviour [Chapter 21 in

Wagner D, Stevenson H (eds.), Czrltzrral Persp ect ive s on Ch ild develop men^. SanFrancisco, CA: W.H. Freeman and Company; l982,2O-S3.McGraw M. Growrh: A Stzrdy of Johnny and Jimmy. New York,NY: Appleton-

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McGraw M. The Nezcromzrsnilar Matzrration of the Htrman Infant. New York NY:Columbia University Press; 1945.

Mulligan L, Specker B, BuckleyD, OYConner ,Ho M. Physical and environmentalfactors affecting motor development, activity level, and body composition ofinfants in child care centers. Pediatr Phys Ther 1998;10:156-161.

Parker S. Greer S, Zuckerman B. Double jeopardy: the impact of poverty on earlychild development. Pediatr C hNorth Am 1988;3 5 :1227-1240.

Piper M. Darrah J. Motor Assessment of the Developing Iltfmlt. Philadelphia, PA:W.B. Saunders; 1994.

Ramey C, Farren D.Campbell F. Predicting IQ fiom mother-infant interactions. ChildDev 1979;50:804-8 14.

Raze1M. Call for a follow-up study of experiments on long-term deprivation of humaninfants. Percept M o m Skills 1988;67: 147-158.Super C. Environmental effects on motor development: the case of 'African infant

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Appendix A

Initial Questionnaire


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Infant Motor Development and the Home Environment:Initiaf Questionnaire

Andrea Abbon, Dr. Doreen Bartlett, and Dr. John Kramer, School of Physical Therapy,The University of Western Ontario

By filling out this form, you as the main caregiver of your baby, will help to determinehow home influences might affect the activities that babies do. All informationconcerning you and your baby will be kept confidential.Your NameYour AddressPostal CodeYour Phone NumberToday's DateFirst. we would l ike to ask a few questions about your baby and y o u r baby'sdelivery.1. What is your baby's name?

(first) (last)2. What was your baby's birth date?

(day) (month) (year)3 . Is your baby a girl or a boy? (circle the number of your answer)

1 Boy2 Girl

4. How much did your baby weigh when born? grams or Ib, - oz5. Howmany weeks pregnant was the mother when your baby was born? weeks6. Were there any complications during the delivery?

fbI f yes, please describe:7. How many days, of a 7 day week, is your baby cared for in your home? days


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Next, a few questions about you. as the main caregiver.8. What is your relationship to your baby? (circle)

1 Mother2 Father3 Other,

9. What is your date of birth? (day) (month) (year)10. Do you have any other children?

1 YES if so, what are their dates of birth?r1o11 . What is the highest level of education that you have completed? (circle)

1 Some High School2 Completed High School3 Some College4 Completed College5 Some University6 Completed University

12. Ethnic group can often influence the timing of when babies do different activities.Which of the followingethnic groups do you consider yourself a part of? [these responsesare adapted from the Statistics Canada 1996 Census Survey]. (circle)

I White (Caucasian)2 Black (e.g. African, Haitian, Jamaican, Somali)3 North American Indian or Metis4 Asian (e-g. Chinese, Japanese, Korean, Cambodian, Indonesian, Laotian,

Vietnamese, Filipino)5 South Asian ( e . g .Armenian, Egyptian, Iranian, Lebanese, Moroccan)6 Other (pieasedescribe)


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We are planning to send out a summary of th e study results after the study is finished. Sothat we are certain to be abIe to contact you over the nest few months. please provide uswi th the name. address. a n d phone number of a close friend or relative who will likelynot move during this time.Name: - -- -. - -- -- - - - -Address:Postal Code:Phone Number:Thank you for filling out this form. Please return it to us in the stamped envelopeprovided. We will mail you a form that looks at th e activities that babies do on theirback, stomach, sitting, and standing wh en your baby is close to 5 months old.If you have any questions, at any time, please call:Andrea Abbott, Master of Science Candidate at 661-3360Dr. Doreen Bartlett, Assistant Professor at 679-2 11 Z ext. 8953Dr. John Kramer, Associate Professor at 66 1-3360


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Appendix B

Item Examples from the HOME Inventory


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Item Examples from the HOME Inventory by Caldwell and Bradley,1984.

(InfantfToddler HOME)

Scoring instructions:Place a plus (+) or minus (-) alongside each item if the behavior is observed during thevisit or if the parent reports that the conditions or events are characteristic of the home

Item examples from each subscale:Subscale I. RESPONSIVITY

2 . Parent responds verbally to child's vocalizations or verbalizations.

Subscale IV. LEARNING MATERIALS29. Parent provides toys for child to play with during visit.

SubscaIe V. INVOLVEMENT37 . Parent consciously encourages developmental advance.


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Appendix C

hstructions and Item Examples f?om the Maternal Version of the AlbertaInfant Motor Scale


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Infa nt M otor Development a nd the Home Environment

Andrea Abbott, Dr. Doreen Bartlett, and Dr. John Krarner, School Of Physical Therapy,The University of Western Ontario.

Thank you for filling out the first form. Would you, as your baby's main caregiver, pleasefill out the folIowing forms.First, could you please write your name and today's date in the space below andanswer the following questions:Your Name:Today's Date:I . What is your relationship to your baby?2. How many days, of a 7 day week, is your baby cared for in your home? days

Now we would like you to look at the a ttached form that looks at what activitiesbabies do while they a re lying on their back, stomach, sitting, and standing.I . Look at each picture on the 5 month form and circle "Y" for YES my baby is doingthis activity at 5 months of age or "N" for NO my baby is NOT doing this activity at 5months of age. Do this for each of the four pages (lying on back, lying on stomachsitting, and standing). The descriptions below each picture should help answer anyquestions you may have.2. Now look at the pictures on the 8 month form and begin with the activities th at yourbaby was doing a t 5 months of age. On this form circle "Y' for YES I believe my babywill be doing this activity at 8 months of age or 'W" for NO I believe my baby will NOTbe doing this activity at 8 months of age. Do this for each of the four pages (lying onback. lying on stomach, sitting, and standing).Thank you for filling out these forms. Please return them to us in the stamped envelopeprovided. We will phone you when your baby is close to turning 8months old to set up a time to come and visit you and your baby in your home for the finalform. If you have any questions, at any time, please call:Andrea Abbott, Master of Science Candidate at 661-3360Dr. Doreen Bartlett, Assistant Professor at 679-21 11 ext. 8953Dr. John Kramer, Associate Professor at 66 1-3360


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Item Examples from the Maternal Version of the Alberta Infant MotorScale (MAIMS)by Bartlett, 1992.

Supine Subscale:Handsto Feet

Prone Subscale:

'Swimming'

SittingSubscale:

Reaches in Sitting

Standing Subscale:

Pulls to StandcStandswith Supportn


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Appendix D

Item Examples fforn the Alberta Mant Motor Scale


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Item Examples from the Alberta Infant Motor Scale (AIMS)by Piper and Darrah, 1994.

Supine Subscale:Rolling Supine to ProneWithout Rotation

Lateral head ngnnngfunk moves as on e u n~ ?

Prone Subscale:

Pivoting-.

RvolsMovement nO mona legsLoterol trunk flexion

Sitting Subscale:We~ght hi f t inUnsustainedSi?tng-

r ..x-

Standing Subscale:

SupportedStandingWith Rotation,-.

\ - . - 70 ./----. .* .3. -;

2otanonof Trunkona ~ehns


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Appendix E

Summary of Data korn Reliability Testing for the HOME Inventory and th eAlberta Infant Motor Scale


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Summary of Data from Reliability Testing for the HOME Inventory and the AlbertaInfant Motor Scale (AIMS) at 8-Months

ID #

Initial Reliability Testing:I

HOME InventoryItem Agreement ( O h )

100

86

92.3

96.4

93

93

2

11

23

7

6

36

AKMS ItemAgreement ( O h )

Follow-up ReliabilityTesting:

92.3

92.5

92.5

100

92

92


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Appendix F

Ethics Approval


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TheUNnTERsITYof WESTERN ONTARIOVice-President Research)Ethics Reuiew Board Derrtal Scicn ces Building

R E V E W BOARD FOR HEALTH SCIENCES RESEARCH W O L V T N G HUMAN SUBJECTS1997-98 CERTlFICATION OF APPROVAL OF HUMAN RESEARCHALL HEALTH SCIENCES RESEARCH INVOLVING HUMAN SUBJECTS AT THE UNIVERSITY OFWESTERNONTARICARRIED OUT IN COMPLIANCE WITH THE MEDIC AL RESEARCH COUNCiL OFCANADA "GUIDELINESO NRESEARCH INVOLVING HUMAN SUBJECT."1997-98REVIEW BOARD MEMBERSHIP1) Dr. B.Bomein. Assistant Dean-Research - Medicine (Chairman) (Anatomy/Ophthalmolog?~)2) Ms. S.Hoddinott. Directo r of Research Senice s (Epidemiology)3) Dr. R Gagnon, St. Joseph's Health Centre Representative (O bstetrics& Gjnaecology)4) Dr. R McManus, London Health Sciences Centre - Victoria Ca mpus R epresentative (Endocrinology & Metabolism)5) Dr. D. Bocking, London Health Sciences Centre - University Campus Representative (Physician - Internal Medicine)6 ) Dr . L. Heller. Of ice of the President Representative (French )7) Mrs. . loncs. Office of the Presiden t Representative (Com munity)8) Ms. S. Fincher-Stoll, Office of the President Representatii-e(Legal)9) Dr. D.Freeman, Faculty of Medicine& Dentis@ Representative (Clinic al)10) Dr. D. Sim. Faculty of Medicine& Dentistq Represenlative (Ba sic) (Ep idem iolo ~)11) Dr. T.M. Underhill, School of Dentistry Representative (Oral Biology)12) Dr. H. Laschinger, School of Nursing R epresentative (Nursing)13 ) Dr. W.S. Yovetich.Facu1ty of Health Sciences Representative (Comm unicative Disorders)14) Ms. M. Luvell. London Clinical Research Association Representati\.e15) Research Institutes Represen tative16) Mrs.R Yohnicki. A dministrative OfficerAlternates are appointed for each member.THE REVIEW BOARD HAS EXAMINED THE RESEARCH PROJECTENTITLED:"Infant motor development and the home environment"REVIEW NO: E64SOAS SUBMITTED BY: Dr. J. Kramer - Physical Therapy, Elborn CollegeAND CONSIDERS ITTO BE ACCEPTABLE ON ETHICAL GROUNDS FOR RESEARCH NVOLWNG HUTi4ANSUBJECTUNDER CONDITIONS OF THE UNIVERSITY'S POLICY ON RESEARCH MVOLVMG HUMAN SUBJECTS.APPROVAL DATE: April 23 1998(UWO rotocol, L etter of Inform ation& Consent)AGENCY:AGENCY TITLE:

c uBessie Bonvein, Chairman C.C. Hospital Administration

London.Ontario Canada N6A 5CI Telephone: (519)661-3036 Fax: 519 )661-3875


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AppendixG

Letter of Information


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InformationKept by FamiliesTitle of the Project: InfantMotor Development and the Home EnvironmentThe purpose of this project is to find out how aspects of the home may affect how babiesmove. The results of this project may improve the fixture care of babies who are havingproblems learning to move.We are asking parents with babies in programs such as Just Beginnings and HealthyMothers-Healthy Babies, parents using the Well Baby Clinics,and parents who havebabies in one of London Bridges Child Care Services to take part in t h i s project. We arelooking for parents who are planning to care for their babies in the home for 4 out of 7days a week until the baby is 8 months old. If you take part, wed sk you o fill out ashort form with questions about you and your baby. When your baby is close to 5months, we will send you a form that looks at how your baby moves on his or her backstomach, sitting, and standing. We will also ask you to mark hose activities you believeyour baby will be doing at 8 months. This will take 30 to 40 minutes to do. We willinclude a stamped, addressed envelope to return these forms to us . Lastly, when yourbaby is close to 8 months, we will call you to set up a good time to meet with you andyour baby at your home. During this time, we wili ask you some more questions aboutyou and your baby. We will also watch how your baby moves while lying on the back,stomach, sitting, and standing. This visit will take about an hour.This studywill not harm you or your baby. At the end of the home visit, we will talk withyou about how your baby moves and what you might expect your baby to do next. Foryour interest, we will send you a short summary of the results after all babies have finishedthe final visit.We will give all records a code number. We will not report any information idenafylngyou or your baby. We will lock all of the information in a filing cabinet and shred it all 5years after the study is finished.Taking part in this study is voluntary. You may refise to take part, refuse to answer anyquestions or withdraw from the study at any time with no effect to you or your baby.Please keep this letter for your information. If you have any questions, at any time, pleasecall:h d r e a Abbott, Master of Science Candidate at 661-3360Dr. Doreen Bartlett, Assistant Professor at 679-2111ext. 8953Dr. John Kiamer, Associate Professor at 661-3 360School of Physical TherapyThe University of Western Ontario1588 Elborn CollegeLondon, Ontario, N6G 1Hl


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Appendix H

Flyer


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ISYOUR BABY3 to 5 MONTHS OLD?

IF SO, WE INVITE YOU TO BE A PART OF APROJECT LOOKING AT HOW BABIES MOVE.If you are interested in taking part in thisproject, please take a letter (below) and call:Andrea Abbott, Master of Science Candidate

661 3360Dr. Doreen Bartlett, Assistant Professor679-2111 (8953)Dr. John Kramer,Associate Professor661-3360

School of Physical TherapyFaculty of Health SciencesThe University of Western Ontario


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Appendix I

Consent Fonn


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Consent FormInfant Motor Development and the Home Environment

I have read t h e accompanying letter of information, have had the nature of the studyexplained to me, and I agree to participate. All questions have been answered to mysatisf

Documents

Infant Motor Development and Home Envt