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Chang, Park, Yoo, and Kim: Changes of Cortical Excitability by Prefrontal tDCS in Patients with Stroke -A case report-
Case Report
Brain & Neurorehabilitation

Brain & Neurorehabilitation 2011; 4(2): 137-143.

Published online: 30 September 2011

DOI: https://doi.org/10.12786/bn.2011.4.2.137

Changes of Cortical Excitability by Prefrontal tDCS in Patients with Stroke -A case report-

Won Hyuk Chang, M.D., Ji-Young Park, Ph.D., Ji Sung Yoo, M.D., Yun-Hee Kim, M.D.

Department of Physical and Rehabilitation Medicine, Stroke and Cerebrovascular Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Korea.

Corresponding author (yunkim@skku.edu, yun1225.kim@samsung.com)

Received 11 February 2011       Accepted 11 May 2011

Copyright © 2011 Korean Society for Neurorehabilitation

Abstract

In this case study with 2 chronic stroke patients, we investigated the nature of modulation of neural activities during the working memory (WM) task by transcranial direct current stimulation (tDCS) over the left dorsolateral prefrontal cortex (DLPFC) using functional MRI (fMRI). Two patients with chronic right hemispheric stroke participated. Patients performed the 2-back WM task within the fMRI scanner before and after tDCS application while the response data were recorded. An anodal tDCS of 1 mA over the left DLPFC was applied for 20 min within fMRI scanner. The accuracy and the recognition accuracy of WM task were improved after applying tDCS. In fMRI images, activation was decreased in the left superior temporal areas in both cases which represent increased efficiency of neural resources after applying the tDCS. The results of this study showed that the effective modulation of cortical activity by tDCS might be a determinant for behavioral changes of enhancing WM function in patients with stroke.

Keywords: functional MRI, stroke, transcranial direct current stimulation, working memory

Figures and Tables

Fig. 1
fMRI results for verbal working memory task at pre-tDCS (A-1, A-2) and post-tDCS (B-1, B-2) in case 1 and 2. Comparison between pre- and post-tDCS fMRI results are presented in C-1 (case 1) and C-2 (case 2) (p<0.005, uncorrected). Red spots represent increased activation and blue spots represent decreased activation after tDCS.
bn-4-137-g001
Table 1
Characteristics of Subjects
bn-4-137-i001

Rt: Right, MCA: Middle cerebral artery, SC: Striatocapsular, SCNT: Seoul Computerized Neuropsychologic Test.

Table 2
fMRI Activation Areas before and after tDCS over the Dorsolateral Prefrontal Cortex in Patients with Stroke
bn-4-137-i002

Lt: Left hemisphere, Rt: Right hemisphere.

Table 3
Increased or Decreased fMRI Activation Areas after tDCS over the Dorsolateral Prefrontal Cortex in Patients with Stroke
bn-4-137-i003

Lt: Left hemisphere, Rt: Right hemisphere.

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