A preliminary study of lateralized processing in attention-deficit/hyperactivity disorder.

Attention-deficit/hyperactivity disorder (ADHD) is associated with deficits in spatial and sustained attention processes normally linked to the right parietal and frontal lobes. However, data on lateralization changes in attention processes are sparse. Little research has addressed whether the problems may reflect a more widespread lateralization disorder or whether there are lateralization changes over time. To address these issues, the authors examined several tasks, each using a lateralized process largely localized to a particular lobe and 2 age ranges (11-14 and 18-26 years) of unmedicated ADHD participants and control participants. ADHD children bisected lines significantly more rightward compared with control children, indicating an altered spatial attention process normally localized to the right parietal lobe. This problem was absent in young adults, suggesting a developmental resolution. The authors observed sustained attention decrements at both ages appearing earlier in the left hemisphere during a vigil. Finally, in these preliminary data, ADHD-related problems appeared specific to attention processes.