Eficácia da neuroestimulação e terapia cognitiva na modulação da atenção na Doença de Alzheimer

Abstract

Alzheimer's disease (AD) is a neurodegenerative disease of unknown cause that represents the most common form of dementia. It is characterized by a progressive decline in the functions of the nervous system, initially affecting memory and its progressing symptoms reaching other cognitive functions such as attention. The changes in attention in AD can make information processing difficult, thus affecting other cognitive processes. AD has no curative treatment, only its symptoms are treated, and pharmacological therapy has low efficacy, high cost and several adverse effects. Due to this context, non-pharmacological therapies, such as Transcranial Direct Current Stimulation (tDCS), a neuromodulation technique based on noninvasive stimulation, and cognitive intervention have been highlighted as adjunctive therapies in the treatment of AD. Thus, the present study aims to evaluate the efficacy contribution of tDCS and cognitive stimulation therapy in modulating the attention in a sample with mild AD. This is a randomized, double-blind, placebo-controlled clinical trial with a sample of 20 patients diagnosed with mild AD randomly assigned to three groups: (a) active tDCS and active cognitive intervention; (b) tDCS sham and active cognitive intervention; and (c) tDCS sham and cognitive intervention placebo. Patients were treated for 8 weeks and evaluated at two times: baseline (T0), week 8 (T2). As a primary outcome measure, attention was assessed by the Trail Making Test, part A (TMT-A), and the Direct Order Digits, Codes, and Symbols tests of the WAISIII scale were measures of secondary outcomes, assessing attention and processing speed. The current intensity applied for tDCS was 2mA. Results showed no significant differences regarding primary and secondary outcomes in pre and post therapy measures and between groups. However, the descriptive values presented higher means in the groups that received the stimulation protocol compared to the placebo group, demonstrating potential effects of the techniques as adjuvant therapy for AD.