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Abstract:
Willams Syndrome (WMS) is a rare genetic disorder resulting
in a complex cognitive profile, including hyperacusis, remarkably
good language functioning, and impaired visuo-spatial functioning.
Previous ERP (Event-Related Potential) studies of WMS have reported
abnormal auditory but normal visual sensory processing. ERPs to
faces, however, a visual task, are strikingly different from
normal. Given the differences in processing sensory stimuli, we
investigated a higher level cognitive task in the two modalities.
In the present two experiments we investigated the processing of
rare visual and auditory stimuli in WMS and controls. Typically, a
positivity beginning around 300 msec post-stimulus (P300) is
elicited to rare, task-relevant stimuli. In the auditory
experiment, subjects heard tones of two different frequencies, and
responded when they heard one of them (p=.10). In the visual
experiment, subjects saw squares of two different colors on a
monitor screen, and responded when they saw a red square (p=.10).
ERPs were recorded at 14 electrodes. In the auditory experiment,
P300 amplitude for targets was smaller for WMS than for controls,
with P300 peak latency increased by 50 msec. In the visual
experiment, P300 amplitude was not significantly different between
groups, however, the trend was the same as for auditory. Results
will be interpreted in the context of the Williams neurocognitive
profile.
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