The BoHA measures spontaneous use and quality of goal directed actions performed with each hand separately as well as with both hands together. The BoHA was developed through adaptation of the Assisting Hand Assessment and scoring is done by observation of bimanual play using the same activities as used in the AHA. Thus, children aged 18 months – 5 years play freely with the toys in the AHA test kit, school children (6-12 years) play one of two alternative board games (Alien game and Fortress game). The AHA test kit, in which the Fortress and the Alien games are included can be ordered from the Handfast webshop.
The outcome of the test renders a separate score for each hand, illustrating possible asymmetric hand use as well as a measure of bimanual performance. The BoHA is scored on 16 items (11 unimanual and 5 bimanual) scored on a 4-point rating scale.