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Abstract:
A decline in spatial working memory have been implicated as
an early cognitive deficits accompanying Parkinsons Disease.
Researchers have reported early stage dopamine depletion from the
rostral caudate nucleus, which receives projections from the
dorsolateral prefrontal cortex. Previous research has shown that
patients are impaired in a memory-guided eye movement task. Here we
describe the performance of Parkinsons patients using a
memory-guided pointing task on a computer touch screen. Of interest
was whether patients showed reduced accuracy as a function of
memory delay. Twelve patients and 12 Elderly Controls were asked to
recall single or four step target sequences with 2 time delays (500
and 3500ms). Patients did not differ from controls in single target
500ms condition. However, they showed increased end point errors as
delay increased to 3500ms. Patients also made more sequence errors
during recall of four-step sequences. Analysis of movement
amplitude revealed that Parkinsons patients tended to undershoot
the 1st location in the movement sequence. Movement amplitude
between the other steps in the sequence did not differ between
patients and controls. The results demonstrate that in the early
stages of Parkinsons disease, patients have a selective deficit in
spatial working memory, thus suggesting basal ganglia involvement
in spatial working memory. Supported by: Burroughs Wellcome Award
1000323 and NIA-AG-14676.
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