Characterizing ‘direct’ bi-manual coordination while adapting to a dynamic environment

A bimanual haptic robot was used to investigate how bimanual coordinated reaching movements are affected by the adaptation to two viscous curl force fields that were applied to the two hands. The workspace and the target sets for each hand were the same. The two force fields could be directed in the same way (for a group of 7 right-handed subjects) or in opposite directions (for another equivalent group). The results show that in both groups bimanual force fields adaptation occurs, in a similar way to the uni-manual studies. However, the coordination of the two hands is affected, in a specific direction-dependent manner, with regards to the longitudinal lag between the two hands.