Rhythmic interlimb coordination arises from the interaction of intrinsic dynamics and behavioral information, that is, intention, memory, or external information specifying the required coordination pattern. This study investigates the influence of the content of memorized behavioral information on coordination in musically experienced and inexperienced participants. These groups are hypothesized to have different intrinsic dynamics for this task. Stability was assessed in a switching task (variability and switching time). The in-phase, antiphase, and 90°-phase difference were specified in a neutral and an ecologically relevant manner. Musicians showed more stable coordination than nonmusicians did. No interaction effect was found with memorized behavioral information. Behavioral information showed an interaction effect with phase pattern on coordination variability, with the strongest effect for the 90°-phase pattern. Switching time was affected largely in line with the findings for coordination variability. Participants showed an intraindividual preference for one type of gallop and one type of switch strategy, suggesting different hand roles.
Martine H.G. Verheul and Reint H. Geuze
Max G. Feltham, Annick Ledebt, Simon J. Bennett, Frederik J.A. Deconinck, Martine H.G. Verheul and Geert J.P. Savelsbergh
The study examined symmetrical bimanual coordination of children with spastic hemiparetic cerebral palsy (SHCP) and a typically developing (TD) control group under conditions of visual feedback created by placing a glass screen, opaque screen or a mirror (“mirror box”) between the arms. The “mirror box” creates a visual illusion, which gives rise to a visual perception of a zero lag, symmetric movement between the two arms. Children with SHCP exhibited a similar mean coordination pattern as the TD control group, but had greater movement variability between the arms. Furthermore, movement variability in children with SHCP was significantly greater in the screen condition compared with the glass and mirror condition, which were similar to each other. The effects of the availability of visual feedback in individuals with hemiparesis are discussed with reference to central and peripheral mechanisms.