Handedness and the asymmetric dynamics of bimanual rhythmic coordination.

Abstract

Human handedness was investigated in a 1:1 interlimb rhythmic coordination in which consistent and inconsistent left-handed and right-handed individuals oscillated hand-held pendulums. Mean phase difference (4> stable ) and its standard deviation (SD4>) were evaluated as functions of mode of coordination (in-phase vs. anti-phase) and the symmetry conditions imposed by controlling the natural frequencies of the left and right pendulums. The dependencies of </> stab)e and SD<f> on coordination mode and imposed symmetry were found to be systematically affected by handedness. The data were consistent with an elaboration of the established order parameter dynamics of interlimb rhythmic coordination. The elaboration includes additional 2i7 periodic terms that break the symmetry of those dynamics when the natural frequencies of the component rhythmic units are identical.

Laterally focused attention modulates asymmetric coupling in rhythmic interlimb coordination

“…Moreover, such an asymmetry in attentional focus affected the stability of bimanual performance, in that focusing on the D limb resulted in enhanced coordinative stability Swinnen et al, 1996). These effects of attentional asymmetries on the bimanual coordination dynamics were similar to those obtained for handedness and were therefore consistent with the asymmetric potential proposed by Treffner and Turvey (1995;see Amazeen et al, 1997;Riley et al, 1997). Furthermore, this correspondence regarding the way in which hand dominance and attentional focus affected the relative phase dynamics was in agreement with Peters' (1989Peters' ( , 1994 suggestion that the effects of handedness during bimanual coordination are related to an attentional bias (see Amazeen et al, 1997).…”

“…Empirically, however, the phase relation between the limbs has been demonstrated to be affected by hand dominance. Typically, for right-handed (RH) participants the right hand is, on average, slightly leading in time, whereas the opposite is true for lefthanded (LH) individuals (e.g., De Poel et al, in press;Semjen, Summers, & Cattaert, 1995;Stucchi & Viviani, 1993;Swinnen, Jardin, & Meulenbroek, 1996;Treffner & Turvey, 1995. For one-dimensional oscillatory movements this implies small but significant deviations (i.e., phase shifts) from the intended relative phases of 0°and 180°.…”

“…These effects of handedness on the relative phasing between the limbs and the associated stability characteristics have been accounted for by extending the HKB potential with additional handedness-related symmetry breaking terms (Treffner & Turvey, 1995). Converging theoretical and empirical results revealed that the identified effects of hand dominance on the coordination dynamics are related to an asymmetry in the strength of the coupling between the limbs.…”

“…Based on the results of Amazeen et al (1997) and the asymmetric potential proposed by Turvey (1995, 1996), variability of / (as a second index of pattern stability) was expected to be higher when attention was focused on the ND limb. Because the (asymmetry in) coordination dynamics is also dependent on the performed coordination mode and movement frequency (e.g., De Poel et al, in press;Treffner & Turvey, 1995, performance was examined for both in-phase and antiphase coordination at two different movement frequencies.…”

“…Although bimanual coordination implies that the two hands work together as a synergy, their roles are not identical. Asymmetries due to hand dominance can be observed for the performance of everyday discrete tasks (e.g., striking a match; Guiard, 1987;Peters, 1994) and rhythmic bimanual movements alike (e.g., Byblow, Bysouth-Young, Summers, & Carson, 1998;Peters & Schwartz, 1989;Summers, Davis, & Byblow, 2002;Treffner & Turvey, 1995). Hand dominance (or handedness) is typically related to neurophysiological asymmetries such as hemispheric dominance (e.g., Haaland & Harrington, 1996;Sainburg, 2002;Serrien, Ivry, & Swinnen, 2006).…”