Effects of Prefrontal Transcranial Direct Current Stimulation on Lexical Access in Chronic Poststroke Aphasia

Background. A successful interplay between prefrontal and domain-specific language areas is critical for language processing. Previous studies involving people with aphasia have shown that executive control processes might act on lexical-semantic representations during retrieval. Modulating the prefrontal control network by means of noninvasive brain stimulation might, therefore, improve lexical access in people with aphasia. Objective. The present study investigates the effects of prefrontal transcranial direct current stimulation (tDCS) on lexical access in chronic poststroke aphasia. Methods. We report data of 14 participants with chronic poststroke aphasia. We used a sham-tDCS (S-tDCS) controlled and double-blind within-subjects design. Performances in picture naming, verbal fluency, and word repetition were assessed immediately after stimulation. Results. As compared with S-tDCS, anodal tDCS (A-tDCS) improved verbal fluency as well as the speed of naming high frequency words, but not word repetition. Conclusion. The results of our study suggest that the brain network dedicated to lexical retrieval processing can be facilitated by A-tDCS over the left dorsolateral prefrontal cortex. This finding supports the notion that strengthening executive control functions after stroke could complement speech and language-focused therapy.

Download Full-text

Proceedings #20: Null Effects of Transcranial Direct Current Stimulation (tDCS) on Verbal Fluency: A Double-Blind, Sham-Controlled Study

Brain Stimulation ◽

10.1016/j.brs.2018.12.189 ◽

2019 ◽

Vol 12 (2) ◽

pp. e83-e84

Author(s):

E. Susan Duncan

Keyword(s):

Direct Current ◽

Transcranial Direct Current Stimulation ◽

Verbal Fluency ◽

Controlled Study ◽

Double Blind ◽

Direct Current Stimulation

Download Full-text

Transcranial direct current stimulation (tDCS) in elderly with mild cognitive impairment: A pilot study

Dementia & Neuropsychologia ◽

10.1590/1980-57642018dn13-020007 ◽

2019 ◽

Vol 13 (2) ◽

pp. 187-195 ◽

Cited By ~ 2

Author(s):

Marcos Alvinair Gomes ◽

Henrique Teruo Akiba ◽

July Silveira Gomes ◽

Alisson Paulino Trevizol ◽

Acioly Luiz Tavares de Lacerda ◽

...

Keyword(s):

Executive Functioning ◽

Direct Current ◽

Transcranial Direct Current Stimulation ◽

Verbal Fluency ◽

Controlled Trial ◽

Test Word ◽

Memory Recall ◽

Double Blind ◽

Significant Group ◽

Direct Current Stimulation

ABSTRACT. Transcranial direct current stimulation (tDCS) is a non-invasive, painless and easy-to use-technology. It can be used in depression, schizophrenia and other neurological disorders. There are no studies about longer usage protocols regarding the ideal duration and weekly frequency of tDCS. Objective: to study the use of tDCS twice a week for longer periods to improve memory in elderly with MCI. Methods: a randomized double-blind controlled trial of anodal tDCS on cognition of 58 elderly aged over 60 years was conducted. A current of 2.0 mA was applied for 30 minutes for 10 sessions, twice a week. The anode was placed over the left dorsolateral prefrontal cortex (LDLFC). Subjects were evaluated before and after 10 sessions by the following tests: CAMCOG, Mini-Mental State Examination (MMSE), Trail Making, Semantic Verbal Fluency (Animals), Boston naming, Clock Drawing Test, Word list memory (WLMT), Direct and Indirect Digit Order (WAIS-III and WMS-III) and N-back. Results: After 10 sessions of tDCS, significant group-time interactions were found for the CAMCOG - executive functioning (χ2 = 3.961, p = 0.047), CAMCOG - verbal fluency (χ2 = 3.869, p = 0.049), CAMCOG - Memory recall (χ2 = 9.749, p = 0.004), and WMLT - recall (χ2 = 7.254, p = 0.007). A decline in performance on the CAMCOG - constructional praxis (χ2 = 4.371, p = 0.037) was found in the tDCS group after intervention. No significant differences were observed between the tDCS and Sham groups for any other tasks. Conclusion: tDCS at 2 mA for 30 min twice a week over 5 consecutive weeks proved superior to placebo (Sham) for improving memory recall, verbal fluency and executive functioning in elderly with MCI.

Download Full-text