Both Hands Assessment for children and adolescents with bilateral cerebral palsy: Content and construct validity

To investigate the content and construct validity of the Both Hands Assessment (BoHA) for children and adolescents with bilateral cerebral palsy (CP), classified in Manual Ability Classification System (MACS) levels I to III, aged 18 months to 18 years.

In this cross-sectional study, we included 61 adolescents with bilateral CP (37 males, 24 females, mean age 15 years 6 months, SD = 2 years 3 months) who were assessed with the BoHA to investigate content validity. Their BoHA results were combined with data from 210 children (121 males, 89 females, mean age 6 years 4 months, SD = 3 years 1 month), resulting in 271 BoHA assessments for the Rasch measurement model analyses investigating construct validity.

After revising the bimanual item 'orients objects', the BoHA items were suitable for scoring bimanual performance in adolescents. Strong internal scale validity and reliable item and person measures were demonstrated for the 16 BoHA items, analysed separately for individuals with asymmetric (n = 94) and symmetric (n = 177) hand use. The BoHA logit measures were linked to the same reference frame, enabling comparable overall bimanual performance measures while maintaining separate item difficulty hierarchies.

The BoHA scale can measure bimanual performance in individuals with bilateral CP, classified in MACS levels I to III, aged 18 months to 18 years. This allows for monitoring development and evaluating the effectiveness of intervention from early childhood to adulthood.