Is Visual Motion Processing Vulnerable to Early Aging?

While many behavioral capacities decline with age, few can be readily noticed in the early stages of aging. Visual motion processing is particularly sensitive to aging; yet it is unclear whether decline in motion processing can be used to index the visual aging process in its early stages. We examined performance in 63 healthy individuals on a series of motion-related visual tasks, in a large age range (21-80 years-old). Three psychophysical tasks were used: dynamic contrast detection (a functional precursor to motion processing), contrast-based velocity discrimination (motion processing dependent upon contrast signal), and velocity discrimination (motion processing independent of contrast modulation). Additionally, cognitive ability was assessed using the WAIS-R (verbal components). Results indicated that visual motion performance began to significantly decline between the 51-60 and 61-70 age groups, and this decline was most pronounced on velocity discrimination tasks. Cognitive performance did not differ across age groups and was not correlated with performance on visual measures. This pattern of results suggests that visual motion processing may be a potential indicator of early aging within the visual system.