Validity and reliability of the 3-meter backward walk test in children with cerebral palsy

ObjectiveTo examine the validity and reliability of 3-Meter Backwalk Test (3MBWT) in children with Cerebral Palsy (CP).MethodsStudy included 55 children with CP with the mean age of 12.34 +/- 3.78 years, at Expanded and Revised Gross Motor Functional Classification System (GMFCS-E;R) I and II levels. Intraclass Correlation Coefficient (ICC) was used for the intra-rater and inter-rater reliability of 3MBWT according to the GMFCS-E;R levels. MDC estimates were calculated using baseline data. Convergent validity of 3MBWT was evaluated with its correlation between the Timed Up and Down Stairs Test (TUDS), Pediatric Balance Scale (PBS), Timed Up and Go Test (TUG), Pediatric Reach Test (PRT), Four Square Step Test (FSST).ResultsIntra-rater and inter-rater reliability of 3MBWT was determined excellent at GMFCS-E;R I (Intra-rater ICC = 0.981-0.987, inter-rater ICC = 0.982-0.993), and GMFCS-E;R II (ICC = 0.927-0.933, ICC = 0.954-0.968). Intra-rater MDC values for GMFCS-E;R I were 1.17-1.22 s (s); 1.40-1.42 s for GMFCS-E;R II. Inter-rater MDC values for GMFCS-E;R I were 1.00-1.28 s, and MDC values for GMFCS-E;R II were 1.08-1.22 s. There was strong correlation between 3MBWT and PBS, TUG, and FSST in GMFCS-E;R I, moderate correlation between 3MBWT and TUDS, strong correlation between BBS, moderate correlation between TUG, and strong correlation between FSST in GMFCS-E;R II (p 0.05).ConclusionThe 3MBWT was found to be valid and reliable in children with CP. According to the MDC results, small differences in CP children can be adequately detected with 3MBWT. The 3MBWT also may add some more information on to GMFCS (E;R) data for following the disease progression as well as rehabilitation responses.