Factor analysis of the WeeFIM in children with spastic cerebral palsy.
PURPOSE
Determining the psychometric properties such as reliability and validity of Functional Independence Measure for Children (WeeFIM) instrument would help health professionals to understand the comprehensive assessment of children with spastic cerebral palsy (CP). The purpose of this study was to investigate the factor structure of the WeeFIM in children with spastic CP.


METHODS
Two hundred seven children (138 boys, 69 girls) with spastic CP were recruited in this cross-sectional study; their mean age (SD) was 9.10 (2.7) years. Data were collected through a questionnaire that included the WeeFIM. Of the 207 children, 57 (27%), 105 (51%), and 45 (22%) were quadriplegic, diplegic, and hemiplegic, respectively. In each of these groups, 49 (24%), 32 (15%), 31 (15%), 19 (9%), and 76 (37%) children were classified as Gross Motor Function Classification System (GMFCS) levels I-V, respectively. The factor structure of the WeeFIM was analyzed by exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) by using AMOS 20.0. The reliability of WeeFIM was assessed by calculating the internal consistency of Cronbach's α.


RESULTS
The internal consistency of Cronbach's α was 0.98. The 1- and 2-factor models did not demonstrate adequate fit indices according to CFA. However, the 3-factor structure (i.e. self-care, motor, and cognitive factors) was supported by EFA and CFA, which explained 87.12% of the variance. The self-care factor included 6 items (eating, grooming, dressing upper, dressing lower, bathing, and toileting), the motor factor included 7 items (bladder and bowel management, bed/chair/wheelchair, toilet, tub/shower, walk/wheelchair, and stairs), and the cognitive factor included the same 5 items as the original cognitive domain.


CONCLUSION
In children with spastic CP, 3 factors of the WeeFIM were determined by factor analysis. Therefore, self-care, motor, and cognitive domains should be treated as separate scales in children with spastic CP.