To compare the amplitude and latency of P1, N1, P2, N2, P300 between the unilateral spatial neglect patients after right hemisphere stroke and normal people, in order to study the spatial attention processing characteristic of unilateral spatial neglect patients, further to explore the mechanism of USN.

Twenty cases (10 USN patients and 10 normal people) were enrolled in the study. We recorded the ERP, and then compared the reaction time and correct rate, the amplitude and latency of P1, N1, P2, N2, P300 when the target appeared in the left and right, to study the mechanism of USN.

The correct rate of the USN group was lower than the Normal group. There were no significant differences between the two groups in P1 amplitude and N2 amplitude. The N1 and P2 amplitude of right hemisphere of the USN group was lower than the normal group. When the target appeared in the left, the P300 amplitude of the USN group was lower than the normal group. The latency of P1, N1, P2, N2, P300 in the USN group was prolonged than the normal group.

During the spatial attention processing, regardless of the stimulus from the left or right, the information processing speed of the USN group slowed down compared with the normal group. In the early stage, there was no significant reduction of activitied neurons. In the mid-stage, the number of activitied neurons was reduced significantly in the right hemisphere. But in the late stage, the number of activitied neurons was reduced significantly when the stimulus from the left side.