Abstract
Using motor imagery to mentally body-scale reach movements represents a significant component in effective motor planning and execution. According to recent reports, older persons have difficulty in mentally representing action via motor imagery. This study examined a group of young adults ( 21 years) and a group of older adults ( 77 years) on their ability to use motor imagery to mentally body-scale reach by estimating whether targets presented were reachable with their dominant limb while seated. Imagined responses were compared to the individual's scaled maximum reach. Each participant received 35 trials randomly presented across seven target distances with five trials per site. ANOVA results indicated that the elderly were significantly less accurate than the younger adults, p < .001. Group responses were similar in peripersonal space, however the older group displayed significantly more error in extrapersonal space. That is, they were stating that targets were reachable, when in fact, targets were out of reach.over-estimating reachability. In summary, this work in general supports the contention that there is a decline in cognitive processing associated with the ability to create internal models and mentally represent action. More specific to this experiment, we observed a significant distinction (decline) in the ability to mentally body-scale reach movements. Explanations include possible deficits in the aging brain, namely the parietal cortex, and visual perception.
