|
Abstract:
Our lab is quantifying eye movement abnormalities in patient
groups with pathophysiology in the frontal cortex and/or basal
ganglia. Saccadic eye movements were measured in 10 Parkinson's
(PD) patients and in age- and sex-matched normal controls.
Characteristics of reflexive and voluntary eye movements were
studied using pro- and antisaccade tasks with and without delays.
In the no-delay condition, the target appeared concurrent with
the eye movement signal. Subjects performed a block of prosaccades
to the visual target followed immediately by two blocks of
antisaccades, eye movements made away from the visual target. In
the delay condition, the target appeared before the signal for
movement initiation; pro- and antisaccade trials were randomly
interleaved. We probed spatial working memory by having subjects
move their eyes to remembered locations of multiple sequential
target steps after an interval of delay. PD patients made saccades
with shorter saccadic reaction times (SRT) in the prosaccade task
and longer SRT in the antisaccade task. Saccade amplitudes were
hypometric. PD patients had more difficulty withholding a voluntary
eye movement until the signal for movement in the delay tasks.
Finally, PD patients made a greater number of sequence errors in
the spatial working memory task. PD patients were better than
control participants at reflexive saccades but worse than the
controls on voluntary saccades.
|
