Electroencephalographic analysis of brain activity after interventions with transcranial direct current stimulation over the motor cortex: a systematic review

Abstract

This study aims to determine processes and procedures for the analysis of the behavior of brain signals in clinical trials before and after different intervention protocols involving transcranial direct current stimulation (tDCS). In this study, PubMed and Cochrane databases were searched for original articles describing clinical trials that used electroencephalography to analyze the behavior of brain signals after submitted to transcranial direct current stimulation. Searches were conducted with MeSH terms for clinical trials to determine the behavior of brain activity over time through evaluations performed before and after a period of intervention involving tDCS. The search was limited to articles published in English in the last ten years. It was found 257 articles during the initial search, where 14 of which were submitted to an appraisal of methodological quality, and 4 were considered to have adequate quality. Based on the results, there is inconsistency in the processes and procedures used for the acquisition of brain signals, even when limiting the search to clinical trials offering an analysis of evaluations performed before and after clinical interventions. Moreover, researchers seek to offer guidance regarding the acquisition of electroencephalography (EEG) signals to favor the quality of the data but fail to standardize regions for these acquisitions in the analysis of the results of tDCS.