Abstract
Objectives
Cognitive impairment is a common feature in Parkinson's disease (PD) and is an important
predictor of quality of life. Past studies showed that some aspects of cognition,
such as working memory, can be enhanced following dopaminergic therapy and transcranial
magnetic stimulation. The aim of our study was to investigate whether another form
of noninvasive brain stimulation, anodal transcranial direct current stimulation (tDCS),
which increases cortical excitability, is associated with a change in a working memory
task performance in PD patients.
Methods
We studied 18 patients (12 men and 6 women) with idiopathic PD. The patients performed
a three-back working memory task during active anodal tDCS of the left dorsolateral
prefrontal cortex (LDLPFC), anodal tDCS of the primary motor cortex (M1) or sham tDCS.
In addition, patients underwent two different types of stimulation with different
intensities: 1 and 2 mA.
Results
The results of this study show a significant improvement in working memory as indexed
by task accuracy, after active anodal tDCS of the LDLPFC with 2 mA. The other conditions
of stimulation: sham tDCS, anodal tDCS of LDLPFC with 1 mA or anodal tDCS of M1 did
not result in a significant task performance change.
Conclusion
tDCS may exert a beneficial effect on working memory in PD patients that depends on
the intensity and site of stimulation. This effect might be explained by the local
increase in the excitability of the dorsolateral prefrontal cortex.
Keywords
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Article info
Publication history
Accepted:
May 26,
2006
Received in revised form:
April 24,
2006
Received:
February 20,
2006
Identification
Copyright
© 2006 Elsevier B.V. Published by Elsevier Inc. All rights reserved.
