The effects of consecutive sessions of anodal transcranial direct current stimulation over the primary motor cortex on hand function in healthy older adults.
Introduction: The aim of the current study was to investigate the effect of 5 consecutive daily session of anodal transcranial Direct Current Stimulation (a-tDCS) over the primary motor cortex (M1) on the hand function in healthy older adults. Method: This was a randomized, double-blinded, sham-controlled study which 32 participants involved in the study in two different groups ( a-tDCS group: 8 male, 8 female, and sham tDCS group: 8 male, 8 female). The intervention group received 20 minutes of 1 mA a-tDCS over the M1 for five days. The sham tDCS group received the same stimulation while the tDCS device was turned off after 30 seconds of stimulation. Participants performed the Purdue Pegboard Test(PPT) on the first day before tDCS application, immediately(T1), 30 minutes(T2), and one week after the last session (5th day)(T3) of the stimulation. Results: Post-test assessments compared to baseline showed significant improvement for PPT(p < 0.05) in the a-tDCS group at all post-test values except for perdue pegboard test for left hand subtest (PPTL) at T1. Compared to the sham group, the results indicated significant improvement in all PPT subtests (P<0.05), except for PPT for the left hand at T1, PPT for both hands at T2 and PPT assembly at T3 in the a-tDCS group. Conclusion: These findings suggest a-tDCS can be considered as a promising stand-alone technique in the intervention of the age-related decline of manual dexterity for improving hand function.