Driving Simulator Performance in Adolescents with Autism Spectrum Disorder: The Role of Executive Functions and Basic Motor Skills

Friday, May 15, 2015: 5:30 PM-7:00 PM
Imperial Ballroom (Grand America Hotel)
S. M. Cox1, D. J. Cox2, M. J. Kofler1, M. A. Moncrief2, R. E. Reeve1, R. J. Johnson2 and A. E. Lambert2, (1)Curry School of Education, University of Virginia, Charlottesville, VA, (2)Psychiatry and Neurobehavioral Sciences, University of Virginia, Charlottesville, VA
Background: The recent increase in research on motor vehicle driving for individuals with autism spectrum disorder (ASD) reflects an improved understanding of the disorder’s lifetime course and changing functional impairments across development. Previous studies have shown that individuals with ASD demonstrate poorer driving performance than their peers and are less likely to obtain a driver’s license.

Objectives: The purpose of this study is to examine the association between driving performance, basic skills, and executive functioning among adolescents and young adults with and without ASD using a sophisticated virtual reality driving simulator (VRDS).

Methods: Forty-four males (ages 15-23), 17 with ASD and 27 healthy controls, completed paradigms assessing driving skills and executive functioning. The VRDS protocol involved two types of tests: Tactical and Operational. The Tactical test employed a standardized route, during which participants negotiate realistic road and traffic demands (both expected and unexpected). Operational tests assess driving-relevant basic skills and executive function abilities (dual processing, response inhibition, working memory) using driving-specific stimuli, requiring driving-specific responses in a driving-relevant context.

Results: Consistent with previous investigations, results from the tactical drive revealed that adolescents with ASD demonstrated poorer overall driving ability relative to novice drivers without ASD. Additionally, drivers with ASD had significantly slower reaction times during steering (d = 1.45) but not braking. Results also revealed that there was a significant interaction effect attributable to the differential effects of adding working memory demands (road sign recall task) for ASD relative to non-ASD adolescents. That is, between-group differences in steering/braking did not reach significance for either the response inhibition (p = .146) or working memory (p = .174) conditions. However, the increase in working memory demands was associated with a significant one-tailed decrease in steering/braking performance for the ASD group (p = .10, d = -0.45) relative to a significant increase in steering/braking performance for the comparison group (p = .016, d = 0.54).  In contrast, adolescent drivers with ASD performed similarly to healthy control adolescents on driving tests assessing their ability to flexibly shift between steering and braking as well as successfully inhibiting responses at similarly high levels relative to healthy control adolescents.

Conclusions: Deficits in executive functioning have been well-documented in the ASD literature; this study’s findings highlight the influential role these higher order abilities play in driving performance for this population. Interestingly, the ASD group did not demonstrate impaired performance during response inhibition or dual processing tasks, whereas the addition of a working memory task differentially impacted drivers with ASD. For these drivers, working memory abilities, but not motor speed, served as a significant covariate of driving ability, suggesting that working memory may reflect an important mechanism underlying some of these drivers’ on-road difficulties. Clinically, these findings suggest that driver training programs for adolescents with ASD may provide maximum benefit through repeated practice of scenarios that place relatively high demands on working memory (e.g., multitasking) in addition, or in place of more basic driving skills.