Age-Related Deficits in Visuospatial Memory Are due to Changes in Preparatory Set and Eye-Hand Coordination.

Objectives: Healthy aging is associated with a decline in visuospatial working memory. The nature of the changes leading to this decline in response of the eye and/or hand is still under debate. This study aims to establish whether impairments observed in performance on cognitive tasks are due to actual cognitive effects or are caused by motor-related eye-hand coordination.

Methods: We implemented a computerized version of the Corsi span task. The eye and touch responses of healthy young and older adults were recorded to a series of remembered targets on a screen.

Results: Results revealed differences in fixation strategies between the young and the old with increasing cognitive demand, which resulted in higher error rates in the older group. We observed increasing reaction times and durations between fixations and touches to targets, with increasing memory load and delays in both the eye and the hand in the older adults.

Discussion: Our results show that older adults have difficulty maintaining a "preparatory set" for durations longer than 5 s and with increases in memory load. Attentional differences cannot account for our results, and differences in age groups appear to be principally memory related. Older adults reveal poorer eye-hand coordination, which is further confounded by increasing delay and complexity.