RESUMEN
OBJECTIVES: To assess the reliability and validity of the Wheelchair Assessment Instrument for people with Multiple Sclerosis (WAIMS), a test to measure driving skills in manual wheelchair users with multiple sclerosis (MS). DESIGN: Three test trials per subject were conducted by 2 raters to examine reliability (inter- and intrarater) and validity (concurrent and construct). SETTING: A national multiple sclerosis rehabilitation center. PARTICIPANTS: Convenience sample of manual wheelchair users with MS (n=50), participating in an inpatient or outpatient rehabilitation program in a national multiple sclerosis center. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The WAIMS consists of 8 items and results in 3 final test scores: ability sum score, performance time sum score, and covered distance. These 3 scores are used to calculate inter- and intrarater reliability, concurrent validity, and construct validity. Concerning validity, the test scores on the WAIMS are compared with (1) the Belgian medical prescription of a wheelchair on the item d445 (hand and arm use), based on the International Classification of Functioning, Disability and Health, (2) the Expanded Disability Status Scale, and (3) the mobility (wheelchair) item of the FIM. RESULTS: Intrarater reliability was found to be higher than interrater reliability. Except for the interrater reliability of the ability sum score, all intraclass correlation coefficients met our standard of 0.80. Concurrent validity was rather low, but construct validity showed that the WAIMS is a valid instrument to assess driving skills in manual wheelchair users with MS. CONCLUSIONS: The WAIMS is a promising tool to assess driving skills in manual wheelchair users with MS, but it needs some refinements and future studies to confirm this statement.