Research Papers

Application of the "Screen for the Identification of cognitively impaired Medically At-Risk Drivers": Preliminary results from the Candrive driver cohort

Filename FINAL-PAPER-99.docx
Filesize 23 KB
Version 1
Date added June 10, 2012
Downloaded 5 times/fois
Category 2012 CMRSC XXII Banff
Tags Session 2A
Author/Auteur Michel Bédard, Shawn Marshall, Malcolm Man-Son-Hing, Bruce Weaver


With the aging of the population there is concern that older drivers will pose a safety risk to themselves and to other road users. While the majority of older drivers are safe, some may have a cognitive impairment that increases their risk of being involved in a crash. The gold standard to assess driving skills remains the comprehensive assessment conducted by Occupational Therapists. However, in the majority of provinces and territories physicians are expected to report older drivers whom they feel may be unsafe to drive.

Over the years many tools have been proposed to help physicians detect older drivers who may be unsafe to drive or for whom a comprehensive evaluation may be indicated. Tools such as the Trail Making Test, Clock Drawing, and Motor-Free Visual Perception Test are just a few that have been mentioned as having the best predictive value. However, most researchers would agree that at present, there are no valid, easy to use paper and pencil tools that allow physicians to determine fitness to drive with adequate precision. This leaves a void and places physicians in a very difficult situation. Dobbs and Schopflocher, in the article they published in 2010, claimed to have developed a tool that has "a high degree of accuracy [and] that can be used for immediate decisions in the clinical setting." The tool, called the "Screening Tool for the Identification of Cognitively Impaired Medically At-Risk Drivers: A modification of the DemTect (SIMARD-MD), is a paper and pencil test easily administered in a physician's office. The SIMARD-MD is a derivative of the DemTect, which was developed to identify mild cognitive impairment in older adults, not to identify unsafe driving. The methodology underlying the testing and validation of the SIMARD-MD has been criticized, and its value questioned. Despite that, and despite the absence of any independent replication of the single study by Dobbs and Schopflocher, the SIMARD-MD was adopted by British Columbia as part of their recommended process to screen drivers.

The purpose of the study reported here was to use data from the Candrive cohort of drivers to determine the outcome of the tool's application in a sample obtained from the general population. More specifically, we sought to determine how many drivers may lose their license, or be required to undergo further driving evaluation, or be considered safe to drive, based on the application of the cut-points proposed by Dobbs and Schopflocher.

Michel Bédard, Shawn Marshall, Malcolm Man-Son-Hing, Bruce Weaver