Visual spatial attention in children with attention deficit hyperactivity disorder.

BACKGROUND Attention deficit hyperactivity disorder (ADHD) was characterized by deficit in the attention mechanism. Until now, the visual-spatial attention deficit in children with ADHD remains controversial. We report a study of the visual spatial attention to assess covert shifts of attention and sustained attention theoretically linked to two neuroanatomically defined attentional system in the posterior and anterior parts of the human brain. METHODS Using the Neuroscan system, the reaction time (RT) was measured according to three different within-subject conditions including cueing (valid, invalid and neutral); delay (800 msec and 100 msec); side [right visual field (RVF) and left visual field (LVF)] as well as one between-subject condition (healthy, ADHD). RESULTS The AHDH group showed slower RTs overall (RT = 760 msec) than the comparison group (RT = 650 msec) (p = 0.001). RTs in the delayed condition of 800 msec (RT = 680 msec) were faster than in the delayed condition of 100 msec (RT = 730 msec) in all children (p < 0.001). The ADHD group showed significant lateral differences in RT (RTRVF: 880 msec > RTLVF: 830 msec) in the 100 msec delay for the invalid cueing condition (p = 0.045) that was not found in the comparison group. CONCLUSION General dysfunction including posterior-based covert shift of attention and anterior-based sustained attention was found in ADHD group. Furthermore, asymmetric left parietal dysfunction in the disengaged operation was noted in those with ADHD.