Tampering with temporal coordination: effects of a sensory device on asymmetries in timing precision between dominant and non-dominant effectors.

Differences between dominant hand (Dh) and non-dominant hand (NDh) performances in a wide variety of goal-directed movements have been associated with functional cerebral specialization and a different use of strategies of sensorimotor control. Also, numerous studies investigating temporal coordination have demonstrated that the Dh has advantages in speed as well as timing consistency over the NDh when rhythmic actions are performed at maximal speed. While between-hand differences have been explored in depth, only a few studies have discussed how flexible are these differences and whether they can be modulated. Recently, we demonstrated that kinesiotape (KT), a band with elastic properties, improves significantly the timing consistency of isochronous wrist's flexion-extensions (IWFEs) when applied on the skin of dominant motor effector. We argued that the augmented precision of IWFEs is determined by a more efficient motor control during movements due to the extra-proprioceptive effect provided by KT. In this study we investigated whether KT is able to modify the expected differences of timing precision between Dh and NDh. Twenty-five healthy subjects, tested with KT and without KT (NKT), have participated in two sessions (KT and NKT cases) in which sets of IWFEs were performed, unimanually with Dh and NDh, in a synchronization-continuation task. Kinematics was recorded and temporal parameters were extracted and analyzed. We studied IWFEs performed at two inter-onset intervals (IOIs) of 800-ms and 550-ms. Results indicate that timing precision asymmetries between Dh and NDh are present when IWFEs are performed. However, the superiority of Dh in timing precision declined in favor of NDh when slower IWFEs movements (800-ms IOI) are performed, suggesting a preferred temporal environment specific for the dominant and the non-dominant motor effector. The application of KT for IWFEs performed at 550-ms IOI helped to increase significantly the timing precision in both hands. At 550-ms IOI, the NDh-KT case outperformed significantly the Dh-NKT, showing that KT not only counteracts the precision disadvantage of the NDh, but makes it more precise than the Dh. These responses were not evident when IWFEs were performed at 800-ms IOI, suggesting that the effect of KT is frequency dependent. The asymmetry between hands, here demonstrated as preferred temporal environment, could, more in general, reflect limb differences in the choice of sensorimotor control strategies for the production of human movement. In addition, our results suggest that an external device, such KT, may modulate motor asymmetries in a flexible manner.