A pilot study examining the effects of transcranial direct current stimulation on cognitive and visual impairments

Objective: The study aimed to assess the impact of a single session of transcranial direct current stimulation (tDCS) on people with both cognitive and visual impairments. Methods: Sixteen individuals with visual and cognitive impairments were recruited and randomized to either the experimental or sham group. While the sham group only received 30 seconds of initial stimulation, participants in the experimental group received an active tDCS intervention for 20 minutes. The Cantonese Mini-Mental State Examination (CMMSE), the Digit Span Forward Test, the Chinese Verbal Learning Test (CVVLT), and the memory subtest from the Neurobehavioral Cognitive Status Examination (NCSE) were the neuropsychological assessments. To ascertain whether there are statistical differences between groups, repeated measures ANOVA was used to analyze data gathered prior to and following the intervention. Results: Age, educational attainment, and baseline CMMSE scores did not significantly differ between the groups. The type of stimulation and CVVLT total scores showed a significant interaction effect, with improvements in scores seen after active tDCS treatment. Other measured variables did not show any additional effects that were statistically significant. Conclusion: These findings provided preliminary support for the potential efficacy of tDCS in improving immediate memory functions among individuals with both cognitive and visual deficits.