Spatial attention in individuals with pervasive developmental disorders using the gap overlap task.

The present study examined spatial attention in individuals with pervasive developmental disorders (PDD) using the gap overlap task and analyzed the express saccade, which is defined by its extremely short reaction time, as a measure of the state of attention. Participants were required to move their eyes to the target stimulus appearing on the left or right side of a fixation point. In this task, participants had to disengage their attention from the central fixation point and shift it to the peripheral target stimulus. In the gap condition, the fixation point disappeared 200 ms before the target stimulus was presented, and in the overlap condition, the fixation point remained while the target stimulus was presented. Saccade latencies were not different between the groups. However, the express saccade was more frequent in the PDD group than in the normal group in the overlap condition. We conclude that individuals with PDD have deficiencies in attentional engagement. Moreover, our study suggests that analysis of the express saccade will be useful in further examinations of attentional processes in PDD.