Does parent report measure performance? A study of the construct validity of the Functional Mobility Scale.
OBJECTIVE
Parental report is often relied on to measure performance of activities in children with cerebral palsy (CP). This study examined whether the Functional Mobility Scale (FMS) accurately reflects performance of mobility in children with CP.


METHODS
Eighteen children with spastic CP (11 males, seven females; mean age 12 y 8 mo, SD 2 y 8 mo, range 8-17 y) were recruited from a special development school. Children were in Gross Motor Function Classification System (GMFCS) levels II (n=5), III (n=4), or IV (n=9), and had quadriplegia (n=9), diplegia (n=7), or hemiplegia (n=2). The children's mobility was observed directly around and outside the home and at school and their mobility methods were recorded. The parent's FMS rating was obtained on the telephone by a physiotherapist. Agreement between direct observation and the FMS rating was examined using quadratic weighted kappa (kappa) statistics.


RESULTS
Agreement between direct observation and the FMS was as follows: FMS 5m kappa=0.71, 45%; FMS 50m kappa=0.76, 94%; FMS 500m kappa=0.74, 95%. Differences in the range and number of mobility methods were observed by GMFCS level across environmental settings.


CONCLUSIONS
Substantial agreement was found between FMS ratings and direct observation, particularly over longer distances, providing evidence of the validity of the FMS as a measure of performance in children with CP.
Harvey
Adrienne
A
McMaster Child Health Research Institute, Hamilton, Ontario, Canada. harvey.adrienne@gmail.com
Baker
Richard
R
Morris
Meg E
ME
Hough
Janet
J
Hughes
Marty
M
Graham
H Kerr
HK
D000203:Activities of Daily Living; D000293:Adolescent; D002547:Cerebral Palsy / Q000145:classification* / Q000503:physiopathology*; D002648:Child; D002657:Child Development / Q000502:physiology*; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008297:Male; D051346:Mobility Limitation; D009043:Motor Activity / Q000502:physiology*; D015588:Observer Variation; D010290:Parents / Q000523:psychology*; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires; D013997:Time Factors