The Relationship between Older Drivers' Performance on the Driving Observation Schedule (eDOS) and Cognitive Performance.

Abstract

Research question/objective: The Driving Observation Schedule (eDOS) was developed for use in the Candrive/Ozcandrive five-year prospective study of older drivers to observe the driving behavior of older drivers and monitor changes in driving behaviors over time. The aim of this study is to describe participants' driving performance during the eDOS driving task and investigate the association between driving performance and cognitive measures.

Methods: A subset of Ozcandrive participants (n = 144, 104 male [72%], 40 female [28%], Mean age = 81.49 years, SD = 3.58 years, Range: 76 - 96 years) completed the eDOS driving task. Participants drove to their selected destinations (up to 4 locations), with observations of driving behaviors (both inappropriate and appropriate) recorded for specific driving maneuvers: intersection negotiation, lane-changing, merging, low speed maneuvers and maneuver-free driving. Driving behaviors (e.g. signalling, speed regulation, gap acceptance, lane position, 'critical errors') were scored by a trained observer and participants received an overall eDOS driving task score (Maximum = 100 points). Participants also completed a series of cognitive assessments as part of the Year 2 Candrive/Ozcandrive assessment protocols.

Results: The overall eDOS driving task score was very high (M = 95.77; SD = 5.15; Range = 65.63 - 100). Detailed analyses of participants' driving behavior revealed a high level of appropriate driving behavior (96%, n = 5,935 maneuvers), with few errors (4%, n = 252 maneuvers). While most participants' performance on the cognitive assessments was high, some scores were below the criteria for cogntive impairment (BIC) according to conventional benchmarks: (MoCA: M = 26.56, SD = 2.12, Range = 19 - 30, % BIC = 28%; MMSE: M = 29.10, SD = 1.01, Range = 26-30, %BIC = 0%; Trails B: M = 111.66, SD = 43.53, Range = 50 - 301, %BIC = 6%). There was no significant relationship observed between participants' overall eDOS driving task scores and age (r (144) = -0.17, p > 0.05), and performance on various cognitive assessments including: MoCA (r (144) = 0.07, p > 0.1), MMSE (r (144) = 0.03, p > 0.5), Trail Making Test B (r (144) = 0.09, p > 0.1).

Implications: Preliminary analyses of the eDOS driving task revealed a high level of appropriate driving behavior among Ozcandrive older drivers. Despite some participants' cognitive performance suggesting impairment, participants' overall eDOS driving task scores were not significantly related to cognitive performance. This finding is consistent with previous research suggesting some older drivers are able to compensate well for age-related cognitive impairment.