Efeitos da Eletroestimulação Transcraniana por Corrente Contínua no desempenho cognitivo e funcional de idosos saudáveis

Abstract

INTRODUCTION: In recent decades, treatments for neurological dysfunctions have made great advances. These advances are linked to new treatment techniques, including non-invasive brain stimulation procedures. Transcranial Direct Current Stimulation (tDCS) is one such procedure, which stands out for its safety and practicality. OBJECTIVE: To analyze the effects of tDCS on cognition, level of anxiety/depression, and mobility in older adults. METHODS: Forty-two participants, mean age of 71.6 ± 7.5 years, were divided into three groups. Group 1, characterized as experimental, underwent active tDCS technique, with electrodes positioned in the participant's dorsolateral left prefrontal area of the brain. Group 2 was considered a placebo group since the stimulation device was attached to the participant but remained turned off. Group 3, characterized as a cognitive-control group, underwent an alternative cognitive treatment, performing crossword puzzles. The follow-up period was 8 weeks, totaling 16 sessions in groups 1 and 2, and 16 crossword puzzles exposed to group 3. For cognitive evaluation, researchers applied the Mini-Mental State Examination (MMSE), the Frontal Assessment Battery (FAB), and the Semantic Verbal Fluency Test (VFT). The level of anxiety and depression was measured with the Hospital Anxiety and Depression Scale (HADS). The participants' mobility was assessed by the Timed Up and Go (TUG) test, applied conventionally and with dual motor and cognitive tasks. The statistical procedures involved multiple and univariate analyses of variance, comparing main effects of the factors group (group 1 × group 2 × group 3), moments (initial × final), and interactions (group × moment). Significance was set at 5%. RESULTS: After eight weeks, no significant benefits were observed in the tDCS group compared to the placebo and control groups for cognition (p=0.557), level of anxiety and depression (p=0.356), and mobility (p=0.871). Cognition showed positive oscillations during assessments (p=0.001). However, as this trend was observed in all the groups, it is more likely that it was a learning response of the participants to the cognitive instruments rather than an effect of tDCS. CONCLUSION: Eight weeks of tDCS were not sufficient to promote significant benefits on cognitive, mental, and motor variables of older adults. This finding differs from other studies that identify benefits of tDCS. Further studies should be conducted to investigate the use of tDCS in older adults. This study was prospectively registered (ID: RBR-4nq8cbp; https://ensaiosclinicos.gov.br/rg/RBR-4nq8cbp).