P 90. Motor performance improvements following tDCS and skill practice in older adults: Implications for motor skill training

Abstract

Introduction Neural degeneration accompanies healthy ageing, reducing the ability to perform activities of daily living. Transcranial direct current stimulation (tDCS) is an emerging technique with the potential to alter neuronal excitability. Although mechanisms of tDCS have been described, limited studies have examined whether tDCS can enhance performance benefits of motor skill training. Moreover, the most effective electrode montage to improve motor performance in older adults has not been explored. Objectives The current study compared the effects of unilateral and bilateral tDCS combined with one session of skill practice, on corticospinal excitability, short-interval intracortical inhibition (SICI) and motor performance of the non-dominant limb in older adults. Materials and methods In a double blinded cross-over design, nine participants (age 55–85 yrs.) underwent 15 min of unilateral, bilateral or sham tDCS (1 mA) combined with five minutes of visuomotor tracking of the wrist. In all three conditions, the anode was positioned over the optimal site for the non-dominant extensor carpi radialis longus muscle. The order of conditions were counterbalanced and separated by a one week wash out. Transcranial magnetic stimulation and visuomotor tracking error assessed neurological function and motor performance at baseline, immediately after and 30 min following the cessation of stimulation. Results Unilateral and bilateral tDCS improved visoumotor tracking error relative to sham, immediately post (15% & 21% respectively) and at 30 min following stimulation (both p Conclusions Unilateral and bilateral tDCS modulated elements of cortical plasticity, irrespective of the electrode montage. These changes outlasted the stimulation period with subsequent changes in motor performance, relative to motor practice alone. These findings provide preliminary evidence for tDCS to preserve or improve motor control in the elderly.