Psychometric properties of the WeeFIM in children with cerebral palsy in Turkey

Abstract

The Functional Independence Measure for Children (WeeFIM) instrument has recently been adapted and validated for non-disabled children in Turkey. The aim of this study was to validate the instrument in children with cerebral palsy (CP). One hundred and thirty-four children with CP were assessed using the WeeFIM. Reliability was tested by internal consistency, intraclass and interrater correlation coefficients (ICCs), internal construct validity by Rasch analysis, and external construct validity by correlation with the Denver II Development Test (Denver II). Mean age of the participants (70 females, 64 males) was 4y 6mo (SD 3y 8mo, range 6mo-16y). CP type was: diplegia in 37.3%, hemiplegia in 20.2%, quadriplegia in 8.2%, 'baby at risk' (i.e. infants who show neuromotor delay but cannot be classified in a CP type) in 29.9%, and other in 4.5%. Reliability of the WeeFIM was excellent with high Cronbach's alpha and ICC values ranging between 0.91 and 0.98 for the motor and cognitive scales. After collapsing response categories, both motor and cognitive scales met Rasch model expectations. Unidimensionality of the motor scale was confirmed after adjustment for local dependency of items. There was no substantive differential item functioning and strict unidimensionality for both scales was shown by analysis of the residuals. External construct validity was supported by expected high correlations with developmental ages determined by the social, fine motor function, language, and gross motor function domains of the Denver II. We conclude that the WeeFIM is a reliable and valid instrument for evaluating the functional status of Turkish children with CP.