When it comes to simultaneous processing of two tasks, information processing capacity is usually below par and not desirable. Therefore, this preliminary study aimed to investigate the effect of transcranial direct-current stimulation (tDCS) of dorsolateral prefrontal cortex (DLPFC) on performing dual tasks. Twenty-six students (average age 25.2 ± 2.43 years) were selected and then randomly divided into experimental and sham groups. All of the participants conducted the Stroop effect test in a dual task situation before and after the tDCS. This test included two intervals between the stimuli of 100 and 900 ms. The results of mixed-ANOVA showed that the average second reaction time of the experimental stimulated group was reduced (in both dual tasks with congruent and incongruent stimuli) significantly after the tDCS. Therefore, it can be stated that the tDCS of the DLPFC increases the information processing speed and the capacity of attention and, as a result, decreases the effect of the psychological refractory period.

Objectives Given the reduction of the ability to correctly predict stimuli, the aging process is often associated with an increase in reaction time. This is particularly more pronounced in the elderly. The neurofeedback program can influence the cognitive function and physical performance by auto-tuning the brain wave abnormalities. The main objective of the current study was to investigate the impact of neurofeedback exercises upon the improvement of the reaction time in elderly, passive males. Methods & Materials The study was a quasi-experimental research in which 18 elderly males, with an average (SD) age of 65.38 (3.12) years, were selected and randomly assigned in experimental and control groups. A YB-1000 reaction timer was used to evaluate the reaction time of the subjects across 3 sets of measurements (pretests, midtests, and posttests). The subjects in the experimental group participated in 12 neurofeedback exercise sessions (increase of beta and decrease of theta powers). To eliminate the impact of empathy, the control group was subject to a similar training plan in which they only observed the recorded waves of the experimental group exercises. Results Statistical analysis of the results based on the MANCOVA test demonstrated a significant improvement in the reaction time of the experimental group compared with the control group following the neurofeedback exercising (P<0.5). Conclusion Based on the reinforcement or inhibition of the brain waves as well as the improvement of the memory use, neurofeedback exercises can serve as an effective means to improve the cognitive processes (e.g. the reaction time) of the elderly.