Development of the Assisting Hand Assessment: A Rasch-built Measure intended for Children with Unilateral Upper Limb Impairments

The purpose of this paper was to report on the first step in the development of a new instrument, the Assisting Hand Assessment (AHA), that measure the effectiveness with which a child with unilateral impairment makes use of his/her affected hand in bimanual activity performance. The assessment is intended for children with hemiplegic cerebral palsy or obstetric brachial plexus palsy, from age 18 months to 5 years. The AHA is conducted through observations of performance skills exposed during play where toys requiring bimanual handling are used. The validity and reliability of the measures were explored using a Rasch measurement model for analysis. In the AHA, 22 items consisting of observable actions are scored on a 4-point rating scale evaluating the quality of the performance. The Rasch analysis suggests that the test rationale, the usefulness of the assisting hand, does form a unidimensional construct and that the items represent the tested phenomenon well. The results show potential for the AHA to become a useful tool for both clinical practice and research.