The Gross Motor Performance Measure: Validity and Responsiveness ...

Research RepoH

The Gross Motor Performance Measure: Validity and Responsiveness of a Measure of Quality of Movement

Background and Purpose. Zbis article presents the results of a study to validate a measure of gross motorperformance for its capacity to detect changes in the quality of movement in children with cerebral palsy aged 0 to 12 years. Subjects and Methods. On two occasions, 4 to 6 months apart, physical therapistsfrom three children's treatment centers assessed 106 children with cerebralpalsy, 18 children who had sustained a n acute head injury, and 29 nondisabled children. Validity was demonstrated by comparing changes on the measure across diagnoses, severity, and age groups. Results. Several a priori hypotheses were supported; however, relationships with parent and therapist ratings were not clearly demonstrated. Conclusion and Discussioa Zbe measure was found to be differentially responsive to changes in '%tablenand "responsiue"groups. (Boyce WF, Gowland C,Rosenbaum PL, et al. Zbe Gross Motor Performance Measure: validity and responsiveness of a measure of quality of movement. Phys Zber. 1995; 75.603- 613.1

William F Boyce Carolyn Gowland Peter L Rosenbaum M a y Lane Nancy Plews Charles H Goldsmith Dianne J Russell Virginia Wrlght Shelley Potter Deborah Harding

Key Words: Cerebral palsy, G m motor behavior, Measurement, Movement, Validity.

Research in the field of cerebral palsy (CP) has been hampered by a lack of reliable, valid, and responsive measures of physical function. In particular, before studies of treatment efficacy or effectiveness can be implemented, there is a need for good measures of gross motor behavior.' Gross motor behavior in children with CP has been conceptualized as having two main features: function and performan~e.~ We use the term "gross motor function" to describe the accomplishment of motor activities, or how much the child does, for example, standing independently for 10 seconds. In this context, "function" does not necessarily refer to activities that are purposeful to the child or performed in everyday settings. Instead, functional activities are defined as traditbnal gross motor milestone

behaviors that can be tested in a standardized manner.

ments to measure change in motor function and performance over time.'

The term "gross motor performance" describes the quality of motor activities, or how well the chdd does the activity, for example, the degree of stability when standing. The importance of motor performance to overall motor behavior in children is reflected in the work of Bobath,3 Rood,4and Bly.5 Numerous authors 6-8 have described the need to develop instruments to measure this feature.

The Gross Motor Function Measure (GMFM) has demonstrated high levels of validity, reliability, and responsiveness in the assessment of motor function in children with CP.1° The GMFM consists of 88 items organized into five dimensions: lying and rolling; sitting; crawling and kneeling; standing; and walking, running, and jumping. Although these items do not assess children within different environmental contexts, nor do they represent activities chosen by children themselves, they were chosen by therapists as important for developmental progress and amenable to change.10~"During a previous study, we determined that an additional instrument was required to measure performance, or the qualitative aspects of motor behavior that are characteristic of children with CP but

Since 1984, researchers at McMaster University, Queen's University, and the Hugh MacMillan Rehabilitation Centre in Ontario, Canada, have conducted a series of studies to develop gross motor measures for use with children with CP. The purpose of these studies has been to design and validate instru-

Physical Therapy /Volume 75, Number 7 /July 1995

603 / 27

that are not measured adequately by other motor measures.12 Initially, we developed the Gross Motor Performance Measure (GMPM) after reviewing the literature relative to attributes of gross motor performance. Definitions were written for 33 attribute~.~' Through nominal group process meetings, 30 developmental therapists from five children's treatment centres in southern Ontario helped to reduce the number of attributes to 5 and to develop attribute scales.l3 An international panel of experts working in academic and clinical settings provided judgments on content validity of the GMPM using a Delph consensus method. Results indicated that the GMPM had satisfactory completeness, clarity, and potential for evaluating changes in motor performance.l4 The GMPM is a criterion-referenced observational instrument that can be

administered with a minimum of equipment in less than 1 hour, depending on assessor skill, developmental stage, and cooperation of the child. The measure consists of 20 items derived from the GMFM, each of which is matched with three designated attributes of performance. Possible attributes to be assessed include alignment, stability, coordination, weight shift, and dissociation. Children are assessed only on items in which they can achieve at least a partial GMFM score, meaning that they can initiate an activity, thereby allowing an assessment of motor quality. Thus, some children have motor performance assessed on all 20 items, whereas others are assessed on as few as 2 or 3 items. Attributes are scored on individualized five-point scales varying from 1 ("severely abnormal") to 5 (''consistently normal"). (See Appendixes 1 and 2 for attribute d e h tions, sample GMPM item, and scale.) Raw scores are summarized into a

WF Boyce, MSc, PT, is Assistant Professor, School of Rehabilitation Therapy and the Departments of Paediatrics and Community Health and Epidemiology, Queen's University, Kingston, Ontario, Canada K7L 3N6 ([email protected]).Address all correspondence to Mr Boyce. C Gowland, MHSc, PT, is Associate Professor, School of Occupational Therapy and Physiotherapy, Faculty of Health Sciences, McMaster University, Hamilton, Ontario, Canada L8N 325. P Rosenbaum, MD, is Professor of Paediatrics, Faculty of Health Sciences, McMaster University, and Director of Paediatrics, Chedoke Child and Family Centre, Chedoke-McMaster Hospitals, Hamilton, Ontario, Canada. M Lane, PT, is Physiotherapist, Halton Parent-Infant Program, Oakville, and Clinical Consultant, Neurodevelopmental Clinical Research Unit, McMaster University. N Plews, PT, is Research Physiotherapist, Chedoke-McMaster Hospitals. CH Goldsmith, PhD, was Professor, Department of Clinical Epidemiology and Biostatistics, Faculty of Health Sciences, McMaster University, when this study was completed. Dr Goldsmith is currently with St Joseph's Hospital/McMaster University, Center for Evaluation of MedicinesBiostatistics, Martha Wing, 50 Charlton Ave E, Hamilton, Ontario, Canada L8N 4A6. DJ Russell, MSc, is Research Coordinator (Neurodevelopmental Clinical Research Unit), Department of Clinical Epidemiology and Biostatistics, Faculty of Health Sciences, McMaster University. V Wright, MSc, PT, is Research Physiotherapist, Hugh MacMillan Rehabilitation Centre, Toronto,

Ontario, Canada M4G 1R8. S Potter, BSc, PT, is Senior Therapist, Niagara Peninsula Children's Centre, St Catharines, Ontario, Canada L2R 7A7. D Harding, BSc, PT, is Physiotherapist, Metropolitan Toronto School Board, Toronto, Ontario, Canada M2P 1B6. This study was approved by ethics review boards of Queens University, McMaster University, and the Hugh MacMillan Rehabilitation Centre. This study was supported by funding from the National Health Research and Development Proesam (Grant No. 6606-3740) . . of Health and Welfare Canada. The studv was coordinated at the Child ~ e v e l o ~ m e Centre, nt Hotel Dieu Hospital, Department of ~ a e i a t r i c s Queen's , University, Kingston, Ontario, Canada.

total score and subscale attribute scores. These scores are expressed as percentages of the maximum possible score relative to the number of items performed.

Validation Hypotheses Because there is not an accepted criterion evaluative measure of overall motor performance for children with CP,12direct tests of criterion validity could not be conducted. Hypotheses were dficult to develop because there is minimal motor control theory applicable to this heterogeneous population.l5 In addition, there are no longitudinal studies of the natural history of motor performance in children with CP. Thus, we developed hypotheses from the knowledge base of investigators and therapists experienced in working with this population. In addition, experience with the GMFM development gave us information and ideas we could use to formulate hypotheses about potential change in motor performance. We believe that construct validity of the GMPM could be tested by formulating a series a priori about how change scores on the GMPM would be associated with different study groups and with changes in function. We expected that diferences in performance of motor activities in different groups of children could be assessed by comparing scores among groups of children with CP, children with other neurological problems, and children without neurological problems. We expected that the GMPM change scores would be greatest in a group of children with acute neurological injuries, such as head injury, as these children often recover rapidly from their injuries and frequently have marked improvements in performance attributes such as coordination and stability. -

-

Change in children disabilities were expected to be minima1 because these children should already have normal quality of movement, although there may be slight changes in performance as children

This article was submitted December 3, 1993, and was accepted February 24, 1995.

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Physical Therapy / Volume 75, Number 7 /July 1995

learn new motor behaviors such as walking. Developmental changes in motor skills and performance generally slow as children mature; therefore, younger children with CP were expected to show more change in GMPM scores than older children. Change scores in children with CP were expected to be greater in those with d d e r impairments or disabilities and less in those with more severe problems. Classification of impairment severity into mild, moderate, and severe categories is a common, yet relatively untested, clinical and research practice. Recent evidence from plots of GMFM scores against clinician's assessments of "severity" in children with CP, however, shows distinct patterns of motor function in these dfierent groups (Rosenbaum PL, Russell DJ; unpublished research). Although reliability data are not available, the face validity of this categorization of severity for motor function may extend to the assessment of gross motor performance, which is also a strong characteristic of movement of children with CP. We anticipated that changes in the GMPM were likely to be positively correlated with changes in function as measured by the GMFM because improvement in a child's quality of movement, or performance, could contribute to change in the child's gross motor skills. We also recognized that the relationship between change in motor function and change in performance would not necessarily be strong. Concurrent validity of the GMPM was tested through comparison with independent parent and therapist ratings of motor performance. In a previous study,1° measures of parent and therapist ratings of children's motor function were demonstrated to be reliable in this population. We expected therapist ratings to correlate more highly with the GMPM than parent ratings because therapists were familiar with the concepts of performance used in the GMIJM,whereas parents were not. Parents' judgments of changes were expected to be based on their evaluaPhysical Therapy / Volume 75, Numbe

tion of what the child does in daily life and thus more focused on function than performance. Five hypotheses were formulated to test the validity of the GMPM: 1. Hypothesis l-Children with head injuries will have greater changes in GMPM scores over time than children in other groups. Nondisabled children will show smaller changes than children in other groups. 2. Hypothesis 2-Children with CP classified by therapists as "mild or "moderate" will have greater changes in GMPM scores over time than those with CP classified as "severe." 3. Hypothesis %Infants with CP will show more changes in GMPM scores over time than toddlers and older children. 4. Hypothesis 4-GMPM change scores will have a low to moderate correlation ( r r 30) with GMFM change scores. 5. Hypothesis 5-Correlations between change scores on the GMPM instrument and therapist ratings of change will be moderate ( r r .55). Correlations of GMPM change scores with parent ratings of change will be slightly lower ( r r .45).

Responsiveness An evaluative instrument is responsive if there is a high likelihood of detect-

ing a treatment effect even if that effect is small.16A responsive measure will allow one to be confident of detecting a change, through inspection af the change score, should a change actually occur. An appropriate measure of responsiveness can be obtained by relating the variability in test scores of stable individuals to the dfierence in scores of individuals who are changing.16 The objective of this validation study was to examine the measurement properties of the GMPM. Validity (con-

struct, concurrent), reliability (interrater, intrarater, test-retest), and responsiveness of the instrument were investigated with the assumption that the primary use of the GMPM would be to evaluate change in the performance of common gross motor activities over time. This assumption has implications for the criteria used to judge the measure.17 The purpose of this article is to report the validity and responsiveness findings of that study. Results from reliability analyses are reported elsewhere (see article by Gowland and colleagues in this issue of Physical nerapy)).

Method On the basis of available ~nformation regarding variability in motor performance scores and possible effect sizes, we estimated that we would need a sample size of 180 children to appropriately examine our hypotheses. We initially planned to recruit 120 children with CP, 30 chddren who had sustained an acute head injury (HI), and 30 children without neurological problems from three children's treatment centers. The latter two groups were included to provide comparative samples in which changes in gross motor performance were likely to be either dramatic (HI) or minimal (no disability). We considered the sample size adequate for analysis because onetailed 95% confidence intervals would vary from .74 to .84 if validation correlations of r > .80 were obtained for an overall effect. We contend that this correlation level is acceptable when using intraclass correlation coefficients (ICCs) and is based on our experience in previous validation studies of the GMFM.7 The final enrollment was 106 in the group of children with CP, 18 in the group of children with HI, and 29 in the group of children without neurological problems, for a total of 153 children. This final sample size was limited by the willingness of children and their families to participate in a lengthy study requiring multiple assessments. The children with CP and HI were receiving various forms and intensities of therapy. Because we

I Table I. Validation Study Sample Severity of Impairment

Diagnostic Group

Age (Y)

Cerebral palsy

0 -2

8

3- 4

10

15

5- 6

2

13

7-1 2

5

11

Mild

Moderate

Severe

Total

15

Total

25

54

Head injury

0-19

6

7

Nondisabled

0-2 3- 6 Total

wanted to study the ability of a measure to detect changes in motor performance, and not to attribute any changes in performance to therapeutic efficacy, we did not consider it important to classlfy children according to treatment status. Children with CP were selected to provide a range of age and severity of neurological involvement. Children with either CP or HI were categorized into mild, moderate, and severe groups by the referring therapist. This categorization was based on criteria for severity that were in common use at the participating study centers. Children in the HI group were all in the early (7

5-6

3-4

x

SO

X

SO

X

SD

F

df

Table 7.

Correlations Between Change on Gross Motor Performance Measure (GMPM) and Gross Motor Function Measures (GMFM) and Change in Quality Judged by Parents and Therapists

P,

Parent (n=el) Mild

2.6

Therapist (n=81)

8.2

(n=7) Moderate

1.6

Hypothesis

6.3

GMPM change

(n=14) Severe

3.1

GMFM change

8.2

(n=5)

.45 -.06 .44'

.55 .22 .40

"One-tailed probability, P,5.05.

F=0.12 df =2,25 P2= ,8874

'Two-tailed probability, P2s.05

and GMPM are measuring dfierent constructs of motor behavior.

Hypothesis 5 The hypothesis that the correlations between the GMPM change scores

and the therapist ratings of change would be moderate is not supported by the data (Tab. 7). Correlations between GMPM change scores and judgments of parents ( r = -.06) and therapists ( r = .22) were low. To determine whether judgments were being

Table 6.

Correlations Between Gross Motor Function Measure and Gross Motor Performance Measure Total Scores for Various Study Groupsa n

Time 1

Group Nondisabled Head injury Cerebral palsy Severity of impairment Mild Moderate Severe Age (Y) 0 -2

Time 2

Change

made on the basis of changes in gross motor function as we have defined it rather than performance, correlations were also calculated for GMFM change scores. These correlations were moderate and significant for parent ratings ( r = .44) but not for therapist ratings (r=.40). These results indicate that structured assessments of gross motor performance as measured by the GMPM were not strongly l~nkedwith clinicians' perceptions of changes in quality of movement.

Responsiveness Through analysis of the therapists' responsiveness subscales, we identified subgroups of 36 "stable" and 60 "responsive" children with CP (Tab. 8). The "stable" group showed no difference between first and second assessments in total GMPM scores (F= 2.13; df=1,35; P2=.1533).This finding indicates that the "stable" group had little variability in GMPM scores over time and were not changing in motor performance. The "responsive" group, however, showed change in GMPM scores between the first and second assessments (F= 12.30; df = 1,59; P2=.0009). Thus, changes in GMPM total scores accurately reflected therapist judgments of overall change in performance in children with CP.

3- 4 5- 6

>7 "Hypothesis r 2 . 3 0 . b~ne-tailedprobability, P , s . 0 5


An analysis of the parents' responsiveness subscales identdied 17 "stable" and 66 "responsive" children with cerebral palsy. There were significant changes in GMPM total scores for both

Table 8.

Cross Motor Performance Measure Mean Total Scores for '5table" and "Responsive"Croups as Identijed by 7herapists and Parents

Time 1

Time 2

Change

Analysis of Variance F

X

SD

X

SD

X

SD

51.2

17.1

52.7

17.7

1.5

6.1

52.6

14.7

55.4

15.2

2.8

8.0

P,

ICC

2.13 1,35

,153

.36

12.30 1,59

,001'

.85

df

Therapist Stable (n=36) Responsive (n=60)

Fisher 2=4.4,P2.05 -

"Two-tailed probability, P,S.05.

the "stable" group (F=9.45; df=1,16; P2=,0073) and the "responsive" group (F=8.97; df= 1,65; P2=.0039). The "stable" group appeared to experience a greater change (4.6 units) than the "responsive" group (2.8 units). These data may indicate parents' lower specific ability to judge overall change in a construct such as motor performance. Intraclass correlation coefficients calculated from the F statistics in this ANOVA showed a diference between the therapist-identified "stable" and "responsive" groups (P2.05). This responsiveness analysis demonstrates the ability of the GMPM to detect change in motor performance in children who have been judged by trained therapists to be changing in their overall quality of movement. This capability is crucial for evaluative instruments being used in clinical trials of treatment effectiveness. Discussion and Conclusions There is sufficient evidence from this study to satisfy a number of our original objectives in assessing the validity 34 / 610

and responsiveness of a measure of quality of movement in a clinical setting. Attributes of gross motor performance can be defined, matched with relevant gross motor function items, and measured with a common scale. A GMPM total score can be generated that may be of use in describing overall motor performance. An event could occur in assessment of very young children or children with severe disabilities, who cannot perform many motor function items, which could have implications for the interpretation of summary scores. The use of percentage scores for individual attributes may occasionally result in attribute scores based on one or a few observations. The contribution of this score to the total score may outweigh its overall importance to the construct of motor performance. Analysis of individual attribute data will allow us to evaluate the impact of this issue and subsequently to make necessary changes to the GMPM scoring procedures. A limiting factor in this study was the low statistical power to detect d&erences between certain subgroups. Although we came close to enrolling a satisfactory number of children in the

study, the number of children in the age X severity groups was often too low to allow us to be confident that we avoided type I1 errors. This issue, combined with the relatively small effect size, or degree of change in motor performance in children with CP, could lead to an inability to detect diferences even if they actually exist. A small effect size may also have contributed to poor correlations between GMPM change scores and parent/ therapist judgment ratings of change. These problems require us to interpret the data with some caution. Other studies have reported similar problems in comparing observational and biomechanical measures of motor performance in children with CP.22 Clinical hypotheses were supported regarding the ability of the GMPM to detect changes in movement quality in children of diferent diagnostic and severity groups. The observation that major improvements in motor performance occurred in older children with CP was unexpected. This pattern of change in motor performance in the older group contrasts sharply with observed change in motor function in a similar population. Russell et all0 reported that the greatest improvement in motor function in children with CP occurred when the children were young. The data from our study tentatively indicated that the greatest improvement in motor performance occurred in both the 3- to 4-year-old children with moderate CP and the older children with moderate CP who had presumably already acquired most of their basic motor skills. These preliminary findings should be investigated further in longitudinal studies with larger sample sizes. Other factors that may contribute to d&erences in motor quality, such as variations in treatment frequency, should also be controlled for in such studies. Hypotheses regarding the relationship between the GMFM and GMPM were partially supported. Further analysis of the data will allow us to explore the critical relationship between function and performance in d&erent severity and age groups of children with CP.


The hypothesis regarding the relationship between GMPM scores and therapist and parent ratings of change was not well supported. The rating task required of the parents and therapists was to estimate the degree of overall change in movement quality of the child. There are several possible explanations for the low correlations observed. The GMPM scores of children with CP changed very little over the two assessments. Therapists' global impressions of these changes may have been influenced by concurrent changes in function as well as by changes in other aspects of motor quality not assessed by the GMPM (eg, speed of movement). In addition, a change that was observed in a single attribute on the GMPM may have ~nfluencedtherapist global ratings. This change, however, may not have been reflected in the total GMPM score. Finally, because the GMPM sampled a small number of the qualitative attributes of movement, it may not have been realistic to expect that overall judgments of movement quality by parents and therapists would be correlated with GMPM change scores. Thus, further refinement of the concepts and improved training of therapists in distinguishing between motor function and performance may be required. The responsiveness analysis, however, supported the use of the GMPM as a measure for evaluating change in motor performance. The initial analysis indicated that the GMPM scores changed in "responsive" groups of children with CP and indicated that when children are independently classhed by therapists as either "stable" or "responsive," changes in the GMPM accurately reflect these groupings. Nonetheless, this finding contrasts with the inability of the therapist and parent rating scales to correlate with GMPM change scores. Alternate wording for "overall change in motor performance" used in the rating scales and the responsiveness subscale may account for the observed findings. This reinforces the conclusion that further work is necessary before the instrument's validity can be fully established. Physical Therapy / Volume 75, Numbe

We believe the GMPM represents an important attempt to construct and validate an observational measure of quality of movement for use with children with CP. Considerable conceptual, methodological, and practical challenges have been partially overcome. Conceptually, there have been advantages in utilizing an existing measure of gross motor function as a source of observable activities. There are also difficulties, however, for observers to distinguish between motor function and performance in scoring activities.

terns of motor behavior in children with CP. Finally, there are many issues of theoretical importance to motor control research that have been identified, such as the relationships between performance, function, age, and severity of impairment. There is also work to be done on validation of the GMPM with other kinematic measures of motor performance and with other populations of children with motor performance impairments. Acknowledgments

In practical terms, the need to simultaneously observe and rate three attributes of performance for each activity has proven a difficult task for therapists. Those therapists who assessed numerous children reported that this task became much easier with experience. A number of these issues must be resolved before the GMPM is ready for use as a measure in a clinical setting. At this time, the GMPM is more suitable for research in controlled settings with well-trained therapists. Further study will be required to determine whether the evaluative properties of the GMPM, or its ability to detect change over time, are as useful as its discriminative properties, such as its ability to discriminate between different diagnostic, severity, and age categories. The availability of a measure of movement quality would allow a fuller assessment of gross motor behaviors in children with CP. Treatments such as neurodevelopmental therapy, use of "tone-reducing"anklefoot orthoses, and dorsal rhizotomy may eventually be tested more completely with the GMFM and GMPM as part of the evaluation protocol. We are continuing to develop an understanding of motor behavior in children with CP. Future work in this area may involve refinement of the GMPM measure as a clinical tool and evaluation of observer training techniques to ensure that potential users are capable of learning and applying this instrument to the complex pat-

We acknowledge the therapists, children, and parents who cooperated in this study. Special thanks are extended to the Children's Developmental Rehabilitation Program, Chedoke-McMaster Hospitals; the Hugh MacMillan Rehabilitation Centre; and the Niagara Peninsula Children's Centre. Diane Tems and Jim Chen assisted greatly with data management and analysis. References 1 Campbell SK. Measurement in developmental therapy: past, present, and future. In: Miller L, ed. Developing Norm-referenced Standardized Tests. Bingharnton, N Y The Haworth Press Inc; 1989:1-13. 2 Hopkins B, Prechtl H. A qualitative approach to the development of movements during early infancy. In: Prechtl H, ed. Continuity of Neural Function From Prenatal to Postnatal Life. Philadelphia, Pa: JB Lippincott CO; 1984:145145. 3 Bobath B, Bobath K. The neurodevelopmental treatment. In: Scrutton D, ed. Management of the Motor Disorders of Children With Cerebral Palsy: Clinics in Developmental Medicine (No. 10). Philadelphia, Pa: JB Lippincott Co; 1984:6-18. 4 Stockmeyer S. An interpretation of the approach of Rood to the treatment of neuromuscular dysfunction. Am J Phys Med. 1%1;46: 900-956. 5 Bly L. 7he Components of Normal Movement During the First Year of Life and Abnormal Motor Development. Oak Park, Ill: NeuroDevelopmental Treatment Association; 1983. 6 Campbell SK. Assessment of the child with central nervous system dysfunction. In Rothstein JM, ed. Measurement in Physical 7hwapy. New York, NY: Churchill Livingstone Inc; 1985:207-228. 7 Scherzer AL, Tscharnuter I. Early Diagnosis and 'Iherapy in Cerebral Palsy. New York, NY: Marcel Dekker Inc; 1982:87-97, 8 Hanis SR. Movement analysis: an aid to early diagnosis of cerebral palsy. Phys 7her. 1991:71:215221.

9 Rosenbaum PL, Russell DJ, Cadman DT, et al. Issues in measuring change in motor function in children with cerebral palsy: a special communication. Phys 7ber. 1990;70: 125-131. 10 Russell DJ, Rosenbaum PL, Cadman DT, et al. The gross motor function measure: a means to evaluate the effects of physical therapy. Dev Med Child Neurol. 1989;31:341-352. 11 Russell DJ, Rosenbaum PL, Gowland C, et al. Manual Gross Motor Function Measure: A Measure of Gross Motor Function in Cerebral Palsy. Hamilton, Ontario, Canada: Chedoke-McMaster Hospitals; 1990. 12 Boyce WF, Russell DJ, Rosenbaum PL, et al. Measuring quality of movement: a review of instruments. Phys 7ber. 1991;71:81> 819. 13 Boyce WF, Goldsmith CH, Gowland C, et al. Development of a quality-of-movement measure for children with cerebral palsy. Phys 7ber. 1991;71:820-832,

14 Boyce WF, Gowland C, Russell DJ, et al. Consensus methodologies in the development and content validation of a gross motor performance measure. Physiotherapy Canada. 1993;45:94-100. 15 Corcos DM. Strategies underlying the control of disordered movement. Phys 7ber. 1991; 7:25-38. 16 Guyatt GH, Walter S, Norman G. Measuring change over time: assessing the usefulness of evaluative instruments. Journal of Chronic Disease. 1987;40:171-178. 17 Kirshner B, Guyatt G. A methodological framework for assessing health indices. Journal of Chronic Disease. 1985;38:27-36. 18 Russell DJ, Rosenbaum PL, Lane M, et al. Training users in the Gross Motor Function Measure: methodological and practical issues. Phys 7ber. 1994;74:630-636. 19 Boyce WF, Gowland C, Rosenbaum PL, et al. Gross Motor Performance Measure for children with cerebral palsy: validation study

design and preliminary findings. Can J Public Health. 1992;83(suppl 21534-S40. 20 Kramer HC, Karner AF.Statistical alternatives in assessing reliability, consistency and individual differences for quantitative measures: application to behavioral measures of neonates. Psycho1 Bull. 1976;83:914-921. 21 Burckhardt C, Goodwin L, Prescott P. The measurement of change in nursing research: statistical considerations. Nun Res. 1982;31: 53-55. 22 Reddihough D, Bach T, Burgess G, et al. Comparison of subjective and objective measures of movement performance of children with cerebral palsy. Deo Med Child Neurol. 1991;33:578-584.

Appendix 1. Gross Motor Peformance Measure Attributes and 7beir Dejinitions Alignment The adjustment or amangement of parts or segments of the body in relation to each other. Coordination The smooth and controlled use of movements in motor performance. This takes into account timing, velocity, direction, force, and amplitude. Dissociated Movement Isolated movement. Movement of one part of the body independent of another part (ie, one limb independent of another limb, or one segment of the limb or trunk independent of another segment). Movement that combines components of different motor patterns (eg, extension of the hip with flexion of the knee). Stability The active maintenance of a body position in the presence of disturbing forces. Weight Shift Movement that involves a transfer of the body's center of gravity. This takes into account amount and direction. The transference can take place in any of the four planes of the body (posteriorly, laterally, anteriorly, and vertically) or any combination of these.


Appendix 2.

Cms Motor Performance Measure Item Example

The child is positionedand asked or encouraged to complete an activity

Gross Motor Function Item Sitting on mat with feet and small toy in front, child leans forward, touches toy, reerects without arm propping

0. Does not lean forward and reerect 1. Leans forward but cannot reerect

2. Leans forward, touches toy, reerects with arm propping

3. Leans forward, touches toy, reerects without arm propping During three repetitions of this activity, the therapist assesses and scores

Gross Motor Performance Attributes Alignment of Trunk and Pelvis 1.

Severely malaligned the majority of the time; majority of movement is executed in the extremes of range inappropriate to the performance of the task

2. Moderately malaligned the majority of the time 3. Mildly malaligned the majority of the time 4.

Demonstrates one trial with completely normal alignment and no evidence of movement pathology

5. Consistently normal alignment for all three trials Dissociated Movements of the Reaching Upper Extremity 1.

No dissociation the majority of the time

2. Moderate impairment of dissociation the majority of the time; absence of efficient movement of one segment relative to another

3. Mild impairment of dissociation the majority of the time 4.

At least one trial with completely normal dissociation, with no evidence of movement pathology

5.

Consistently normal dissociation for all three trials; efficient movement of one segment relative to another within normal variations

Weight Shift 1. Severely abnormal weight shift the majority of the time; inappropriate position of center of gravity; inappropriate direction of weight shift

2. Moderately abnormal weight shift the majority of the time 3. Mildly abnormal weight shift the majority of the time; weight shift always in the appropriate direction 4. At least one trial with completely normal weight shift, with no evidence of movement pathology

5. Consistently normal weight shift for all three trials
