Investigation of the effects of transcranial direct current stimulation and neurofeedback by continuous performance test

Abstract

Transcranial direct current stimulation (tDCS) is a noninvasive neuromodulation technique based on weak direct current stimulation through the scalp. Neurofeedback (NFB) is a learning strategy that may help alter to brain wave parameters, by monitoring electroencephalography (EEG) feedback via special programs. We aimed to investigate the supportive effects of tDCS in addition to NFB training. 16 healthy volunteers were divided equally into two groups. One of the groups was trained by NFB with the sensorimotor rhythm (SMR) protocol; 2 days per week, 10 sessions of 30 min, the other group received 10 min of tDCS before each NFB sessions. Continuous Performance Test (CPT) was used to measure, response time and suppression and to determine selective attention condition. Also, Beck Depression and Anxiety Inventories were used to exclude people with depression and anxiety. Depression scores of NFB + tDCS group were decreased significantly. CPT scores were better at last sessions for both groups compared to the first sessions. Sessions were analyzed by comparing 1st, 2nd, 5th and 10th sessions. While the NFB + tDCS group had statistically significant changes at theta/beta ratios with SMR and alpha band amplitudes, NFB group statistics had changed at theta/SMR ratios. NFB training shows its effects at the end of 10 sessions. Despite an increase in the latencies of correct and commission responses on the task of CPT, additional use of tDCS improves cognitive performance. Also, tDCS has a supportive effect on the healthy participants who have mild anxiety and depression; also inhibition deficits of subjects were clear.