حسین زارع

Abstract The aim of the present study was investigating the effectiveness of Transcranial Direct Current Stimulation (tDCS) on neurocognitive performance in people with mild neurocognitive impairment. Using meta-analysis and integrating the research results, this study has specified the extent of the effect of Transcranial Direct Current Stimulation on improvement of neurocognitive function in people with mild neurocognitive impairment. Method: For meta-analyses Magiran, SID, and Irandoc databases were used to search Persian articles and Science direct, Scopus, and PubMed databases were used to find foreign articles, using ‘MCI’, ‘transcranial direct current stimulation’, tDCS, and ‘mild cognitive impairment’ key words for foreign articles and their Persian equivalents for Persian articles. Of the 29 studies, 11 that were methodologically acceptable were meta-analyzed. The research tool was a meta-analysis checklist. Results: The results of meta-analysis indicated publication bias in the studies. Due to the heterogeneity of the studies, a random effect model was used. The effect of Hedges for the impact of Transcranial Direct Current Stimulation on neurocognitive functions in people with mild neurocognitive impairment was 0.26, which is a large effect. Conclusion: This result shows clinicians can choose transcranial direct current stimulation (tDCS) as effective intervention for patients who suffer from mild cognitive impairments. More investigations are necessary to find the cognitive benefits of using transcranial direct current stimulation in elderly people and other cognitive impaired persons.

The purpose of the present research was to examine the effectiveness of meta-cognitive strategies training on the cognitive failure in patients with general anxiety disorder (GAD). This quasi-experimental design consisted of two groups, with pre-test/ posttest and the control group. Considering the experimental nature of the research and also, with regards to the drop in the number of 30 people (15 in each group), patients with generalized anxiety disorder (DSM-5) were selected according to the available criteria and were randomly assigned to the experimental and control groups according to entry requirements. In both groups, the scale of Broadbent et al. Cognitive Failures Questionnaire (CFQ) was carried out. Then, the experimental group underwent metacognitive strategies in 10 sessions of 90 minutes and the control group did not receive any training. At the end, the same questionnaire was administered in both groups. The results of the two groups were evaluated in two stages using relevant statistical tests. Multivariate covariance analysis showed that meta-cognitive strategies training significantly reduces cognitive failure and its subscales (distraction, memory defects and inadvertent errors) in patients with general anxiety disorder (P<0/05); there was no significant difference between meta-cognitive strategies training with the subscale of not remembering names (P>0/05). Despite the differences in the scores of cognitive failures in the group studied, it is recommended to use metacognitive strategies to reduce the symptoms of cognitive impairment in patients with generalized anxiety disorder.