A discrete aiming head movement task was developed to replicate Fitts’ movement paradigm. Movement time (MT) differences between young (age range 24-29 years, n = 8) and old adults (age range 75-85 years, n = 8) were examined. Cervical spine (CS) range of motion (ROM) was recorded. A head mounted motion capture device was used to evaluate task performance. Three amplitudes and three target widths generated nine indexes of difficulty (IDs). Global ROM was decreased in old adults. The ID and MT relationship was maintained with age; however, old adults were slower, more variable, and more affected by ID. Variations in target size were used as the accuracy variable for both groups. As target size increased, the old population overshot their endpoint. These data support the hypothesis that, besides musculoskeletal slowing with age, there may be age-related deterioration of central processing, planning, or perception mechanisms.
Steven R. Passmore, Jeanmarie Burke and Jim Lyons
Ran Zheng, Ilana D. Naiman, Jessica Skultety, Steven R. Passmore, Jim Lyons and Cheryl M. Glazebrook
Although there are consistent reports that motor skills are affected in individuals with autism, the details are still debated; specifically, why individuals spend more time preparing movements and whether or not movement execution takes longer. The present study investigated if the conflicting reports were related to: (a) differences in movement type and (b) if longer reaction times were related to the time for motor planning or for force-generation processes. Participants performed three different movement types. People with autism had longer premotor reaction times and movement times for the three-dimensional movements only. We suggest individuals with autism have difficulty planning and executing unconstrained reaching movements specifically. The present results are consistent with evidence that autistic individuals have more difficulty effectively using visual feedback but can use tactile feedback to execute reaching movements efficiently and accurately.