Age differences in the control of a precision reach to grasp task within a desktop virtual environment

The purpose of this experiment is to investigate the fine motor performance of young and older adults on a reach to grasp task in a desktop virtual environment with increasing precision requirements. Aging brings about potential loss of an individual's function due to disease, injury, or the degenerative nature of aging itself. Three-dimensional virtual environments have been identified as systems with good potential to ameliorate such problems in older individuals, and precise fine motor skills represent an important class of functional skills. Two groups of participants (Young, n=10, mean age 21.3 years, range 20–24, senior, n=10, mean age 70.7 years, range 60–85) performed a reach to grasp in a desktop virtual environment with simple, low contrast graphics. Results indicate that visual feedback of the hand for sensory guidance of movement did not improve motor performance for either group, and that as precision requirements of the task increased, age group differences in movement time and peak grasp aperture also increased. These findings extend the literature on age group differences in human motor control across the lifespan and differ from previous studies which showed presence of visual feedback of the hand improved motor performance in young adults. Differences in luminance contrast levels in past studies and the current one suggest that control over this feature of the visual scene is an important design consideration for all end-users and warrants additional investigation. Additional recommendations for age-specific design of three dimensional user interfaces include usage of tangibles that are sufficient in size to limit detrimental effects for older adults.