The Effect of Transcranial Direct Current Stimulation Intensity on Motor Performance in Healthy Adults
The Effect of Transcranial Direct Current Stimulation Intensity on Motor Performance in Healthy Adults
to investigate the effect of stimulation intensity on motor performance in healthy adults.
60 healthy subjects were randomly allocated to one of three groups: (a) 20-min of High-Definition transcranial direct current stimulation (HD-tDCS) with an intensity of 2 mA (HD-tDCS 2 mA); (2) 20-min of HD-tDCS with an intensity of 1.5 mA (HD-tDCS 1.5 mA); and (3) 20-min of sham HD-tDCS (HD-tDCS sham). The stimulation was administered noninvasively using an M x N 9-channel high definition transcranial electrical current stimulator from Soterix Medical (New York, NY). The anodal stimulation targeted the right Brodmann area 4 (primary motor cortex) based on HD-Targets brain modelling software (Soterix Medical, New York, NY).
Tests: The non-dominant left arm was tested. The subjects performed a sequential point-to-point movement task on the graphics tablet. Initially, the participants were required to perform 3 sequences without errors to familiarize themselves with the setup, the task and the sequence. Then, they performed the pre-test which consisted of two blocks of 6 sequences, i.e. 12 sequences, with a 30 s break between blocks. Two min after starting the appropriate stimulation, they performed 2 blocks of 6 sequences (identical to the pre-test). After finishing the tDCS stimulation, the participants performed a post-test, which was also identical to the pre-test. The participants returned after 24 hours to perform a retention test, which was equivalent to the pre- and post-tests. Two outcome measures were used: movement time (s) and the reaction time (s) of the reaching movements.
Inclusion Criteria:
Exclusion Criteria: