The Influence of Transcranial Direct Current Stimulation on Skill Acquisition in a Complex Motor Task

Transcranial direct current stimulation (tDCS) applied over the motor cortex (M1) can improve performance in relatively simple motor tasks performed with the hand and arm. Only a few tDCS studies have examined complex, multi-joint tasks. The purpose of this study was to investigate the acute effects of (tDCS) on skill acquisition in a complex, multi-joint arm movement in healthy young adults. 22 right-handed adults were randomly assigned to a tDCS or SHAM group, performing the overhand throws to a target. After the baseline-test block, transcranial magnetic stimulation (TMS) was used to locate the first dorsal interosseus muscle (FDI). Motor evoked potentials (MEP) were recorded in the resting FDI before and after 5 minutes of tDCS (current: 1mA). tDCS was applied for 20 minutes to the FDI muscle while subjects performed 5 practice blocks of overhand throws, ending with a post-test block of overhand throws 5 minutes after the 20-minute stimulation ended. Motor performance was quantified as endpoint error, MEP amplitude quantified cortical excitability. Percent change in endpoint error between the baseline and post-test block for both groups was compared with an unpaired t-test and the percent change in MEP amplitude before and after 5 minutes of tDCS. The percent change in endpoint error was greater for the tDCS group but failed statistical significance (-16.9 vs. -5.2%; P =0.127), the percent change in MEP amplitude was significantly greater for the tDCS group (49.7 vs. -13.5%; P = 0.012). A single-session of tDCS enhances cortical excitability and appears to improve motor skill.https://digitalscholarship.unlv.edu/durep_posters/1023/thumbnail.jp