title: Cognitive functioning differentially predicts different dimensions of older drivers' on-road safety.
abstract: The extent to which deficits in specific cognitive domains contribute to older drivers' safety risk in complex real-world driving tasks is not well understood. We selected 148 drivers older than 70 years of age both with and without neurodegenerative diseases (Alzheimer disease-AD and Parkinson disease-PD) from an existing driving database of older adults. Participant assessments included on-road driving safety and cognitive functioning in visuospatial construction, speed of processing, memory, and executive functioning. The standardized on-road drive test was designed to examine multiple facets of older driver safety including navigation performance (e.g., following a route, identifying landmarks), safety errors while concurrently performing secondary navigation tasks ("on-task" safety errors), and safety errors in the absence of any secondary navigation tasks ("baseline" safety errors). The inter-correlations of these outcome measures were fair to moderate supporting their distinctiveness. Participants with diseases performed worse than the healthy aging group on all driving measures and differences between those with AD and PD were minimal. In multivariate analyses, different domains of cognitive functioning predicted distinct facets of driver safety on road. Memory and set-shifting predicted performance in navigation-related secondary tasks, speed of processing predicted on-task safety errors, and visuospatial construction predicted baseline safety errors. These findings support broad assessments of cognitive functioning to inform decisions regarding older driver safety on the road and suggest navigation performance may be useful in evaluating older driver fitness and restrictions in licensing.
authors.affiliation: Department of Neurology, University of Iowa, Iowa City, IA, USA. Electronic address: Nazan-aksan@uiowa.edu.
authors.forename: Nazan
authors.initials: N
authors.lastname: Aksan
authors.affiliation: Department of Neurology, University of Iowa, Iowa City, IA, USA.
authors.forename: Steve W
authors.initials: SW
authors.lastname: Anderson
authors.affiliation: Department of Biostatistics, University of Iowa, Iowa City, IA, USA.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Dawson
authors.affiliation: Department of Neurology, University of Iowa, Iowa City, IA, USA; Veteran's Administration Health Care System, Iowa City, IA, USA.
authors.forename: Ergun
authors.initials: E
authors.lastname: Uc
authors.affiliation: Department of Neurology, University of Iowa, Iowa City, IA, USA; Department of Mechanical and Industrial Engineering, University of Iowa, Iowa City, IA, USA; Public Policy Center, University of Iowa, Iowa City, IA, USA; Neurological Sciences, University of Nebraska Medical Center, Omaha, NE, USA.
authors.forename: Matthew
authors.initials: M
authors.lastname: Rizzo
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000523:psychology*; D001334:Automobile Driving / Q000523:psychology*; D016022:Case-Control Studies; D003071:Cognition / Q000502:physiology*; D056344:Executive Function / Q000502:physiology; D005260:Female; D006801:Humans; D008004:Licensure; D008297:Male; D008568:Memory / Q000502:physiology; D015999:Multivariate Analysis; D010300:Parkinson Disease / Q000523:psychology*; D012449:Safety; D013647:Task Performance and Analysis
keywords: Aging; Alzheimer’s disease; Cognitive function; Driving safety; On-road test; Parkinson’s disease