Psychometric Properties of Fine Motor Function Measure in Children With Cerebral Palsy: A Rasch Analysis.

Our study utilized Rasch Analysis to examine the psychometric properties of 61-items fine motor function measure (FMFM) in children with cerebral palsy (CP). Partial credit model (PCM) was utilized to test the reliability and validity of FMFM. The response pattern of this samples displayed acceptable fitness to PCM. The analysis results supported the assumption of 1-dimensionality of FMFM. Disordered category thresholds were found in 30 items. Differential item functioning (DIF) was detected in 23 items. Participants with different CP subtypes in different age groups may perform in differently responses patterns. The Rasch analysis produces reliable evidence to support the clinical application of FMFM. Some items may produce inaccurate measurements originated from category structures. Difference in age groups and symptom topography may be associated with variation in fine motor ability among children with CP and leading to unnecessary assessment bias. Hence, FMFM items need modifications to calibrate the former item formulation.