The Role of Temporal Disparity on Audiovisual Integration in Low-Vision Individuals

Recent findings have shown that sounds improve visual detection in low vision individuals when the audiovisual stimuli pairs of stimuli are presented simultaneously and from the same spatial position. The present study purports to investigate the temporal aspects of the audiovisual enhancement effect previously reported. Low vision participants were asked to detect the presence of a visual stimulus (yes/no task) presented either alone or together with an auditory stimulus at different stimulus onset asynchronies (SOAs). In the first experiment, the sound was presented either simultaneously or before the visual stimulus (i.e., SOAs 0, 100, 250, 400ms). The results show that the presence of a task-irrelevant auditory stimulus produced a significant visual detection enhancement in all the conditions. In the second experiment, the sound was either synchronized with, or randomly preceded/lagged behind the visual stimulus (i.e., SOAs 0,+/- 250,+/- 400ms). The visual detection enhancement was reduced in magnitude and limited only to the synchronous condition and to the condition in which the sound stimulus was presented 250ms before the visual stimulus. Taken together, the evidence of the present study seems to suggest that audiovisual interaction in low vision individuals is highly modulated by top-down mechanisms.