Prismatic adaptation reduces biased temporal order judgements in spatial neglect

Visuomotor adaptation to rightward-deviating optical-wedge prisms reduces the clinical manifestations of spatial neglect after right hemisphere damage. We investigated whether this beneficial effect of prism adaptation is due to attenuation of the ipsilesional attentional bias that is common in spatial neglect. Five right hemisphere patients performed visual temporal order judgements before and after visuomotor adaptation to 15° rightward-deviating prisms. The magnitude of patients' ipsilesional attentional bias on the temporal order judgement task was significantly reduced following adaptation. By contrast, the temporal order judgements of normal participants did not change following adaptation to either leftward- or rightward-deviating prisms. The findings suggest that prism adaptation helps to rebalance the distribution of spatial attention following right hemisphere damage.