| |
Abstract:
While much recent research has examined cognitive performance
in children with Attention Deficit Hyperactivity Disorder (ADHD),
few studies have examined patterns of cognitive strengths and
weakness found in adults with this disorder. We report ADHD adults'
performance on a battery of eye movement tasks designed to
elucidate the existence and nature of oculomotor control deficits
in this population. Participants performed four tasks: 1) a
prosaccade gap task that incorporated a 200ms temporal gap between
fixation offset & target onset, 2) a fixation task identical to
the prosaccade task, except for the instruction to keep the eyes
still, 3) a prosaccade no-gap task, & 4) an antisaccade no-gap
task (AST). Using these tasks, we found that individuals with ADHD:
1) did not differ from normal participants in the proportion of
errors (saccades towards distractors) on the fixation task, &
2) made significantly more errors than non-impaired participants on
the AST. These results are consistent with the competitive timing
model of Heron & Roberts (2000), and we examine the proposal
that in adults with ADHD, the speeded activation necessary for
generating an antisaccade may be slowed, leaving them more likely
to make reflexive saccades on the AST. This explanation contrasts
with the proposal that AST performance is impaired in this group as
a result of an overall problem with oculomotor fixation.
|
