How does sensorimotor control change with age? A comparison of visual and pointing performance in older and younger people

Abstract

Introduction: Age-related changes in goal-directed movements may be due to sensory-related or motor-related decline or may also be affected by more generalised slowing of neural processing. There is currently no model that can account for age-related changes to sensorimotor control and its effects on goal-directed movements. We investigated use of visual information for planning and online updating of a rapid movement task. The goal of these experiments was to quantify differences in performance on visual and sensorimotor tasks between older and younger observers. Methods: Older (age range 60-70) and younger (age range: 20-30) observers were screened for visual and motor deficits before testing. We measured visual localisation performance and compared it to pointing performance for targets presented for 100ms or on until touch. We tested two different stimulus durations to investigate how visual information about target location could be used to plan and update movements online. We also used a two step online correction task to further quantify changes in rapid online integration. Results: Although visual localisation was comparable between groups, pointing precision to targets presented for 100ms and on until touch was significantly lower for older people. Movement times for older observers were longer, consistent with previous work. In the two step task, older observers showed a reduced ability to update their movements and longer overall movement times. When forced to reach under time pressure, older observers showed lower accuracy and decreased precision compared to younger observers. Conclusion: Older people show decreased sensorimotor control compared to younger people. Visual performance was comparable across older and younger people, while movements were generally slower. Altogether, results suggest that declines in pointing performance with age reflect changes to sensorimotor integration, particularly online integration of visual information. The implications for current models of sensorimotor control will be discussed.

Meeting abstract presented at VSS 2014