Date Presented 03/27/20
In this study, we will systematically analyze tDCS-based cognitive rehabilitation studies applied to stroke patients in Korea and foreign countries abroad and calculate their effect sizes through meta-analysis. Through this study, tDCS was found to be effective for attention and memory. We have found that the application methods of tDCS differ, suggesting that we need to pay attention to research of formalized tDCS protocols and to foster experts.
Primary Author and Speaker: Min Ah Yang
Contributing Authors: Kyung-A Won, Hye-Yeon Park, Ji-Hyuk Park
INTRODUCTION: Cognitive disorders are caused mainly by brain damage, such as neurodegeneration or stroke, caused by aging. Diller (1993) proposed cognitive rehabilitation to improve cognitive impairment, and the brain plasticity theory becomes the basic theory of cognitive rehabilitation. As structural and functional changes are also demonstrated in adult cerebral cortex, brain plasticity theory-based cognitive rehabilitation programs are being developed and implemented aimed at maximizing residual cognitive functions and achieving neurological compensation for impaired functions. In particular, intervention based on invasive brain stimulation is being highlighted as an alternative. The use of noninvasive brain stimulation in neurological diseases such as stroke is the possibility of adjusting the excitation and plasticity of cerebral cortex. Among noninvasive brain stimulation techniques, transcription direct current stimulation (tDCS) is a technique known as simple and safe, affecting the excitation of the cerebral cortex by attaching anodal or cathodal electrodes to the scalp and causing constant century and positive currents to flow. In neurological disorders, tDCS first began to be applied as a study of the effects of motor function recovery in stroke patients, and later expanded to study language, cognitive impairment, etc. after stroke. In the cognitive rehabilitation study of stroke patients, the use of tDCS is reported to be increasing, and improved attention, memory and executive function. Although it is likely that tDCS will be routinely used for cognitive rehabilitation in stroke patients as the effects of tDCS have been verified through prior studies, it seems difficult to apply to clinical sites due to heterogeneous research methods.
PURPOSE: Interest in tDCS is increasing in the cognitive rehabilitation field of stroke patients, but there is a lack of introduction to the classification of tDCS-based cognitive rehabilitation applied to stroke patients to date and practicality at clinical sites. Therefore, in this study, we will systematically analyze tDCS-based cognitive rehabilitation studies applied to stroke patients in Korea and foreign countries abroad and calculate their effect sizes through meta-analysis to provide information and evidence that can be utilized in Korean clinical or research areas.
STUDY DESIGN: Systematic review and Meta-analysis.
METHOD: These published in Korean and foreign academic journals from 2009 to 2019 were searched through NDSL, RISS, Pubmed and CINAHL. A total of 11 experimental research papers were selected through inclusion and exclusion criteria. This qualitative assessment was conducted, and meta-analysis was performed on the nine result values in seven of these papers using the Comprehensive Meta Analysis 3.0 program.
RESULTS: In the 11 studies, it was found that the amount of electric stimulation, time and area used among researchers was different. In addition, although studies have shown that stimuli have the same cognitive effects, there are differences between studies. In 11 studies, tDCS was applied for about 26 minutes with an average strength of 1.77 mA, and the electrode used was an average size of 28.64cm2. Based on the meta-analysis, the attention of the effects was 0.725, memory 0.796, all of which showed ‘medium effect size’. It was analyzed that there were statistically significant changes in both areas (p<0.05).
CONCLUSION: Through this study, tDCS was found to be effective in the attention and memory of stroke patients. We have found that the application methods of tDCS differ from each other, suggesting that we need to pay attention to research of formalized tDCS protocol and to foster experts.
References
Diller, L., Abreu, B. C., Allen, C. K., Bruce, M. A., Farber, S. D., Fine, S., ... & Zemke, R. (1993). Introduction to cognitive rehabilitation. American Occupational Therapy Association.
Zaghi, S., Acar, M., Hultgren, B., Boggio, P. S., & Fregni, F. (2010). Noninvasive brain stimulation with low-intensity electrical currents: putative mechanisms of action for direct and alternating current stimulation. The Neuroscientist, 16(3), 285-307. doi: 10.1177/1073858409336227
Chi, R. P., Fregni, F., & Snyder, A. W. (2010). Visual memory improved by non-invasive brain stimulation. Brain Research, 1353, 168-175. doi: 10.1016/j.brainres.2010.07.062
Smith, D. V., & Clithero, J. A. (2009). Manipulating executive function with transcranial direct current stimulation. Frontiers in Integrative Neuroscience, 3(1), 1-3. doi: 10.3389/neuro.07.026.2009
