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

Marcos Alvinair Gomes, Henrique Teruo Akiba, July Silveira Gomes, Alisson Paulino Trevizol, Acioly Luiz Tavares de Lacerda, Álvaro Machado Dias, Marcos Alvinair Gomes, Henrique Teruo Akiba, July Silveira Gomes, Alisson Paulino Trevizol, Acioly Luiz Tavares de Lacerda, Álvaro Machado Dias

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.

Keywords: elderly; memory improvement; mild cognitive impairment; tDCS.

Conflict of interest statement

Disclosure: The authors report no conflicts of interest.

Figures

Figure 1. General study design.
Figure 1. General study design.
Figure 2. Boxplot showing results for both…
Figure 2. Boxplot showing results for both groups at pre and post intervention.
*Significant differences (corrected with LSD).

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