Early optimization in finger dexterity of skilled pianists: implication of transcranial stimulation

Abstract

Background: It has been shown that non-invasive transcranial direct current stimulation (tDCS) facilitates motor functions in healthy adults and stroke patients. However, little is known about neuroplastic changes induced by tDCS in highly-trained individuals. Here we addressed this issue by assessing the effect of tDCS on dexterity of finger movements in healthy adult pianists. Twelve pianists practiced bimanual keystrokes in an in-phase manner while bilateral tDCS (left anodal/right cathodal or vice versa) of the primary motor cortex was performed. Before and after stimulation, each participant was asked to perform the trained successive keystrokes, and to repetitively strike a key with each of the fingers as fast and accurate as possible while keeping the remaining fingers immobilized voluntarily.

Results: In contrast to previous findings in untrained individuals, tDCS yielded overall no apparent improvement of fine control of finger movements in the professional pianists. However, for some movement features, pianists who commenced training at later age demonstrated larger improvements of fine motor control following tDCS.

Conclusions: These findings, in combination with lack of any correlation between the age at which pianists commenced the training and motor improvements for sham stimulation conditions, supports the idea that selectively late-started players benefit from tDCS, which we interpret as early optimization of neuroplasticity of the motor system.

Figure 1

Relation between the age at which each player started to play the piano and the difference between pre- and post-tests in terms of variability of the inter-keystroke interval at the right index finger at the RaLc montage (A), variability of the inter-keystroke interval at the left middle finger at the RcLa montage (B), and average of the finger-key contact duration at the left little finger at the RaLc montage (C), respectively. A negative value indicates a decrease (improvement) following the stimulation. Each dot indicates an individual player.