Ipsilateral coordination deficits and central processing requirements associated with coordination as a function of aging.

Young and elderly participants performed concurrent ipsilateral hand-foot movements either isodirectionally or nonisodirectionally. We determined performance by measuring the maximal cycling frequency at which the coordination pattern could be performed successfully (CF(max)). We also determined attentional costs by means of a dual-task paradigm. Findings revealed that CF(max) was significantly lower in the elderly than in the young participants for the nonisodirectional mode, whereas we observed no differences for the isodirectional mode. Under dual-task conditions, coordination deteriorated in the elderly group only. However, when we equated levels of task difficulty, differences between the groups disappeared. Furthermore, attentional costs did not differ between isodirectional and nonisodirectional movements. This indicates that age-related coordination deficits were not primarily evoked by reduced attentional resources or control in elderly persons.