Dropout during a driving simulator study: A survival analysis.

INTRODUCTION: Simulator sickness is the occurrence of motion-sickness like symptoms that can occur during use of simulators and virtual reality technologies. This study investigated individual factors that contributed to simulator sickness and dropout while using a desktop driving simulator. METHOD: Eighty-eight older adult drivers (mean age 72.82±5.42years) attempted a practice drive and two test drives. Participants also completed a battery of cognitive and visual assessments, provided information on their health and driving habits, and reported their experience of simulator sickness symptoms throughout the study. RESULTS: Fifty-two participants dropped out before completing the driving tasks. A time-dependent Cox Proportional Hazards model showed that female gender (HR=2.02), prior motion sickness history (HR=2.22), and Mini-SSQ score (HR=1.55) were associated with dropout. There were no differences between dropouts and completers on any of the cognitive abilities tests. CONCLUSIONS: Older adults are a high-risk group for simulator sickness. Within this group, female gender and prior motion sickness history are related to simulator dropout. Higher reported experience of symptoms of simulator sickness increased rates of dropout. PRACTICAL APPLICATIONS: The results highlight the importance of screening and monitoring of participants in driving simulation studies. Older adults, females, and those with a prior history of motion sickness may be especially at risk.

Cognitive and visual predictors of UFOV performance in older adults.

Eighty two community dwelling older adults (52 females) aged 62-92 years (mean=75) completed a battery of cognitive and visual tests selected to assess functions relevant to driving performance. These were visual acuity, contrast sensitivity, general mental competence (Mini Mental State Examination, MMSE), processing speed (Inspection Time, IT), crowding across the visual field (Proficiency of Peripheral Vision Processing, ProPerVis) and change detection (DriverScan). These six tasks provided predictor variables for performance on the Useful Field of View test (UFOV), a well validated test of fitness to drive that includes subtests for (i) processing speed; (ii) divided attention; and (iii) selective attention. Relative importance regression analyses confirmed that UFOV is sensitive to attentional and speed processes but suggested that subtest (i) primarily reflects visual acuity and contrast sensitivity; subtest (ii) is better explained by change detection and processing speed; and subtest (iii) predominantly reflects crowding and contrast sensitivity. Unexpectedly, given no evidence of substantial cognitive decline, MMSE contributed significantly to performance on the more complex subtests (ii) and (iii).