| |
Abstract:
Previous research in children with ADD/ADHD has shown
impairment in cued-detection tasks that require rapid spatial
shifts of visual attention. We examined whether this impairment
persists when the task requires a temporal, but not spatial, shift
of attention. We investigated two possibilities: (1) that the
temporal allocation of attention to several stimuli may be impaired
in the absence of a spatial component, and (2) that this impairment
occurs in adults with ADD/ADHD. We tested adults with ADD/ADHD
using a standard attentional blink (AB) paradigm. Subjects
identified a target in a rapid serial visual presentation (RSVP)
stimulus stream, then attempted to also detect a probe appearing in
one of 7 post-target serial positions. Compared to controls and to
ADD adults taking dopaminergic medications, unmedicated ADD adults
did not experience improved probe detection as a function of
increasing probe-to-target intervals (450-720 msec). Because target
identification was unimpaired, the difficulty appears to be in
performing a rapid shift of attention between the target and the
subsequent probe. Subsets of all three groups were also tested on a
baseline task (probe detection only); performance of the
unmedicated ADD group was not significantly different from controls
or medicated ADD adults. These results suggest that adults with
ADD/ADHD can direct short-term visual attention towards single
targets, but have difficulty allocating attention to several
stimuli over a brief time interval.
|
