A fast-moving target in the Valpar assembly task improved unimanual and bimanual movements in patients with schizophrenia.

Abstract

To investigate the effects of target speed on unimanual and bimanual movements during a bimanual prehension and assembly task in patients with mild schizophrenia and healthy controls. Fifteen patients with schizophrenia and 15 age- and gender-matched healthy controls were instructed to reach and assemble spacers with both hands for a target that moved at two speeds: fast or slow. Dependent variables were movement kinematics: movement time, number of movement units and timing intervals between both hands. A fast-moving target induced shorter movement times, fewer movement units and shorter timing intervals than did a slow-moving target for patients. Under the slow-target condition, patients had longer movement times and a longer timing interval during prehension, as well as longer movement times, more movement units and a longer timing interval during assembly than did controls. Under the fast-target condition, patients still had slower and less-synchronized prehension than did controls, but their assembly improved to a level similar to that of controls. A fast-moving target induced faster, smoother and more synchronized movements than did a slow-moving target for patients with schizophrenia, especially during assembly. A fast-moving target might elicit faster, smoother, and more synchronized movements than might a slow-moving target during a bimanual assembly task for patients with mild schizophrenia. The findings of impaired movement kinematics under the slow-target condition suggest that patients with schizophrenia need movement training.