Limitation of developmental test to measure functional independence of children: Relationship between the Japanese version of WeeFIM II® and KSPD

PURPOSE: The purpose of the study was to explore whether a developmental test provides enough information to estimate a child's functional independence. The strength of the relationship between developmental level and functional independence of different skills was investigated. METHODS: The participants were 397 children (age 0-7 years) who were referred to NCCHD for suspected developmental delay. The participants' developmental level was measured with the Kyoto Scale of Psychological Development (KSPD) and their functional independence was assessed through a Japanese version of the WeeFIM II (R). To calculate the strengths of the relationship between developmental age (DA) in different domains of the KSPD and WeeFIM II item scores, partial correlation analyses were conducted, controlling for chronological age. RESULTS: Partial correlation coefficients between the score of each of the 18WeeFIM II items and each of the three KSPD domain DAs (controlling chronological age) fell in the ranges of r = 0.169-0.581 (Posture-Motor; P-M), r = 0.377-0.627 (Cognitive-Adaptive; C-A), and r = 0.332-0.655 (Language-Social; L-S). When the participants were divided into three age groups, the correlations ranged from -0.095 to 0.552 for the youngest group (mean age = 14.21 months), from 0.283 to 0.653 for the middle group (mean age = 32.98 months), and from 0.345-0.692 for the oldest group (mean age = 57.48 months), depending on the combinations of the WeeFIM II items/developmental domains of the KSPD. The results indicated that for most of the daily living skills, its functional independence was only partially explained by the scores of a developmental test, once chronological age was controlled. CONCLUSION: This study showed the limitation of a developmental test as a tool to measure the functional independence of children and the necessity of using an independent tool, such as WeeFIM II, to evaluate the level of required support for each daily living skill.