"A bisensory discrete tracking task was used where a probabilistic series of simultaneous auditory and visual stimuli were presented, each stimulus series for response with a separate hand. An auditory and a visual control group each practiced only a unisensory version of the task where response was with one hand . . ‥ The results revealed a net superiority of bisensory over unisensory responding when stimulus events were certain. This was because S in the bisensory task usually made the two response movements together, and anticipation of certain events resulted in an increase in speed of the visual response time to that of the faster audio response time. But, when events were uncertain, impairment was inferred for bisensory responding because the faster audio response time was reduced in speed and synchronized with the slower visual response time." (PsycINFO Database Record (c) 2006 APA, all rights reserved)