The Impact of Multiple Sessions of Anodal Transcranial Direct Current Stimulation on Implicit Motor Learning in...

This study aimed to assess the effects of anodal transcranial direct current stimulation (a-tDCS) of the primary motor cortex on motor learning in high-activity older adults.

Twenty-eight highly active older adults were randomly divided into two groups: sham and a-tDCS groups. During the study, older adults practiced serial response time task for five consecutive days while simultaneously receiving a-tDCS over primary motor cortex. The researchers assessed motor learning by measuring the response time and error rate of sequenced blocks of serial response time task immediately after the intervention, as well as 1 day and 1 week after the completion of intervention.

Results showed a significant interaction effect between groups and time for both response time and error rate (p < .001). Within each group, response time and error rate significantly differed from baseline (Day 1) at postintervention time points (Days 5, 6, and 12; p < .05), except for error rate in the sham transcranial direct current stimulation group between baseline and Day 12 (p = .138). Additionally, significant between-group differences were observed immediately after the intervention (p < .01), and at 1 day and 1 week postintervention, with larger reductions in response time (Days 6 and 12; p < .001) and error rate (Days 6 and 12; p < .05 and p < .01, respectively) in a-tDCS group.

Applying five consecutive sessions of a-tDCS over primary motor cortex induces significant short- and long-term improvements in motor learning among highly active older adults, highlighting strong impacts of a-tDCS on motor learning in this population.