The Effects of Transcranial Direct-Current Stimulation on Cognition in Stroke Patients

Abstract

Background and PurposeTo investigate whether transcranial direct-current stimulation (tDCS) can improve cognition in stroke patients.MethodsForty-five stroke patients (20 males and 25 females, average age: 62.7 years) with cognitive dysfunction were included in this prospective, double-blinded, randomized case–control study. All patients were right-handed and the mean elapsed time after stroke was 39.3 days. Three different treatments groups were used: (1) anodal stimulation of the left anterior temporal lobe, (2) anodal stimulation of the right anterior temporal lobe, and (3) sham stimulation. tDCS was delivered for 30 minutes at 2 mA with 25 cm2 electrodes, five times/week, for a total of 3 weeks, using a Phoresor II Auto Model PM 850 (IOMED®). The evaluation of cognitive impairment was based on a Computerized Neuropsychological Test (CNT), Korean Mini-Mental State Examination (K-MMSE). The Korean version of the Modified Barthel Index (K-MBI) was used to assess activities of daily living functionality. These evaluations were conducted in all patients before and after treatment.ResultsEach group included 15 patients. Pre-treatment evaluation showed no significant differences between the three groups for any of the parameters. There was significant improvement in the verbal learning test on the CNT in the left anodal stimulation group (P < 0.05). There were, however, no significant differences in the K-MMSE or K-MBI scores among the three groups.ConclusionsThese results demonstrated the beneficial effects of anodal tDCS on memory function. Thus, tDCS can successfully be used as a treatment modality for patients with cognitive dysfunction after stroke.

Effects of transcranial direct current stimulation on the working memory of post-stroke people: an integrative review

“…Yun, 2015 (15) To investigate, if transcranial direct current stimulation influences on the cognition of post-stroke individuals. In the intragroup analysis (pre/post treatment) the tests: visual accuracy and visual recognition accuracy improved significantly only in the group 1 (active tDCS).…”

“…The description of all the studies, objectives, sample characteristics, interventions, outcomes and main results are in Table 1. A total of 66 participants (32 male and 34 female), 36 ischemic stroke and 30 hemorrhagic stroke with an average time of 42 days (15)(16)(17) . The interventions were done on the areas F3/F4 (dorsolateral part of the prefrontal cortex) and T3/T4 (temporal anterior lobe) for stimulation in accordance with the international 10-20 system EEG (18) with 2mA current intensity for 30 minutes duration.…”

“…The follow-up was pre/post treatment in all studies, but they differ in the session number. Yun et al (15) presented a total of 15 sessions being 3x/week, Jung et al (16) did only 2 sessions with a 48 hours interval and Park et al (17) didn't report the amount of sessions.…”

“…There was incomplete outcome data and other bias, but selective description did not occur. Yun et al (15) did not describe properly the randomization, allocation concealment, blidind: searcher, participants and outcomes, however, the data was complete, there was not selective description and other bias. The risk of bias of the articles is specified in Figure 2.…”

The application of online transcranial random noise stimulation and perceptual learning in the improvement of visual functions in mild myopia

“…Yet many studies are seeking to understand the mechanisms by which different TES techniques can complement an existing cognitive training (Dhaliwal, Meek, & Modirrousta, 2015;Yun, Chun, & Kim, 2015). tES is non-invasive and if used correctly should not lead to any aversive effects, it is relatively cheap and can be implemented in various contexts as an adjunct to existing techniques, which although are effective in isolation, might not be offering the most optimal treatment to patients.…”