Psychophysical estimation of effects of aging on certain motion perception tasks with application to driving performance

Changes in the demographics indicates that the population older than 65 is on the rise because of aging of the “baby boom” generation and increase in the life span of the individuals due to medical and technological advancements. With this aging trend there is an associated increase in individuals older than 65 with a valid driver's license. Accident statistics over the past few decades also indicate an increase in crash rate per mile driven for the same age group. This trend stresses the need to understand visual perceptual changes that occur with age and their effects on driving. This study focuses on understanding the age related changes in certain motion perception tasks like speed discrimination, direction of heading and time to collision using psychophysical measures.;The first part of the study focuses on changes with age in the above mentioned motion perception tasks. Data was collected from 18 older subjects (older than 60) and 15 younger subjects (18–30 years of age). Statistically significant changes with age were observed for speed discrimination with drifting and radial motion, estimating direction of heading and time to collision. Visual acuity was not found to mediate the observed perceptual changes in visual information processing with age. Gender differences were observed but could be attributed to social and criterion issues rather than differences in neural processing.;Performance in these tasks was potentially believed to have significant correlation with driving performance in the elderly. The second part of the study focuses on relating motion perception test performance in the elderly with useful field of view—an attention based test and a good predictor of identifying at risk elderly drivers, self reported crash rates and driving difficulty. Thresholds on motion perception tasks were higher in subjects who reported to have difficulty in certain aspects of driving and had crashes. The present study provides a qualitative trend on using motion perception tasks as potential visual perceptual correlates in screening elderly drivers who might have difficulty in driving, but the results need to be confirmed by collecting data from a larger cross sectional study for effective quantitative analysis.