ABSTRACT
Aims: To develop a hand function test for children with bilateral cerebral palsy (CP) measuring bimanual performance, including quantification of possible asymmetry of hand use. Method: The Both Hands Assessment (BoHA) content was developed through adaptation of the Assisting Hand Assessment (version 5.0). Data from 171 children with bilateral CP, 22-months to 13 years olds (75 females; mean age: 6 years and 6 months) classified at Manual Ability Classification System (MACS) levels I-III, was entered into Rasch measurement model analyses to evaluate internal scale validity and aspects of reliability. Results: Sixteen items (11 unimanual and 5 bimanual) exhibited evidence for good internal scale validity and item and person reliability when analyzed separately for children with asymmetric or symmetric hand use. By calibrating the BoHA logit measures into the same frame of reference through linking, the overall measure of bimanual performance is comparable between children with asymmetric or symmetric hand use, still allowing use of separate item difficulty hierarchies. Conclusions: The Both Hands Assessment (BoHA), showed strong evidence of internal construct validity for measuring effectiveness of bimanual performance and the extent of asymmetric hand use in children with bilateral cerebral palsy, MACS levels I-III.
Acknowledgments
We want to acknowledge the certified AHA-raters who administered and video-recorded the BoHA test sessions, as well as the children and parents who agreed to participate in this test development study. In addition we want to acknowledge Dr. Mike Linacre for invaluable advices and feedback on the use of the Rasch measurement model.
Declaration of Interest
The second and the last author are both involved in the company Handfast AB (Inc.) which supplies training courses and test material for the Assisting Hand Assessment. The company has not been involved in, or funded, any part of the research.
About the Authors
Ann-Kristin G. Elvrum, OT, PhD, is an occupational therapist specialist in children's health at the Department of Clinical Services at St. Olavs University Hospital in Trondheim, and employed in a post-doctoral position at the Department of Laboratory Medicine, Children's and Women's Health (LBK) at the Norwegian University of Science and Technology in Trondheim, Norway. Britt-Marie Zethrhæus, OT, MSc, is an occupational therapist with extensive experience from children's rehabilitation, employed at the Neuropediatric Unit, Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden. Torstein Vik, MD, PhD, is a Professor of Paediatrics (Perinatal and Paediatric Epidemiology) at the Faculty of Medicine, Department of Laboratory Medicine, Children's and Women's Health (LBK), University of Science and Technology, Trondheim, Norway. Lena Krumlinde-Sundholm, OT, PhD, is an Associate Professor in the Neuropediatric Unit, Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden.