Visual Reaction Time Differences Between Medically-at-Risk Adult Drivers and Healthy Controls

Abstract

Rationale: Visual and cognitive abilities are crucial to the performance of driving and decreased visual processing speed is considered one of the strongest risk factors for poor driving capacity in older adults. Individuals with deficits in visual perceptual skills, specifically scanning or processing speed, will likely have difficulty with judgment and reaction to on-road events. Currently, there are limited assessments of visual processing speed beyond pencil/paper tasks. Purpose: This study examined visual processing speed using the Vision Coach[TM], a visual light board with established normative data for community living adults. Specifically, the research study compared visual reaction times between previous collected data and medically at-risk older drivers with three research questions: (1) is there a statistically significant difference in performance time between medically at-risk individuals and the controls, (2) does the type of medical condition (e.g., neurological, cognition, complex medical conditions) differentiate performance, and (3) does the Vision Coach[TM], differentiate between drivers based on fitness to drive. Design: Data collection was part of a comprehensive driving evaluation with a fitness to drive outcome. The Vision Coach[TM], "Full Field 60" task was used to collect the reaction times used to compare between the two groups, three diagnostic categories, and fitness to drive outcome. Results: Independent t-tests showed a significant difference (p [less-than] .001) in trial times between healthy controls and medically-at-risk adults. No significant difference (p = .141) was found between diagnoses groups. The Vision Coach[TM] was able to differentiate (p [less-than] .001) between those who "passed" and those who "failed" a driving evaluation. Conclusion: Results of this study indicate that being medically-at-risk for driving impacts an individual's ability to quickly react to a visual stimulus. However, diagnosis type does not significantly impact trial time. Lastly, the Vision Coach[TM] was shown to be an effective screening tool for determining fitness to drive.