2010 BC Guide in Determining Fitness to Drive

28.2 Prevalence and incidence of sleep disordersOSAHS affects between at least 2% of women and 4% of men. It is more prevalent amongmiddle aged and older individuals and those who are obese. It commonly remains undiagnosed,with estimates suggesting that 93% of women and 82% of men with moderate to severe sleepapnea are undiagnosed.Canadian data on the prevalence of narcolepsy are lacking. Research in the United Statesindicates a prevalence rate of 47 per 100,000 individuals (.05%). It is more common in men thanin women.28.3 Sleep disorders and adverse driving outcomesNumerous studies have investigated the relationship between OSAHS and adverse drivingoutcomes. The majority of studies indicate that individuals with OSAHS have a 2 to 4 timesgreater risk for a crash, and the crashes result in more severe injuries. Although numerous testsare available to measure daytime sleepiness, the research also indicates that measures of daytimesleepiness and the severity of sleep apnea are not consistent predictors of impairments in drivingperformance.Unlike OSAHS, there are few studies on narcolepsy and adverse driving outcomes. Althoughlimited, this research suggests that narcolepsy is also associated with elevated crash rates.28.4 Effect of sleep disorders on functional ability to driveConditionType of drivingimpairment andassessmentapproachPrimaryfunctionalabilityaffectedAssessment toolsOSAHSNarcolepsyEpisodicimpairment:Medical assessment– likelihood ofimpairmentAll – suddenincapacitationCognitive –reducedalertnessDriver’s MedicalExamination ReportSpecialist’s reportPersistentimpairment:FunctionalassessmentCognitiveDriver’s MedicalExamination ReportCognitive screening toolssuch as; MOCA, MMSE,SIMARD-MD, Trails Aor BDriveABLE assessment344