2010 BC Guide in Determining Fitness to Drive

One study identified that 32.5% of people with Meniere’s disease developed drop attacks(Tumarkin’s otolithic crisis); the attacks typically occurred in a flurry during a period of 1 yearor less. No patient in the study required treatment for the drop attacks. Most people with thishave a spontaneous remission of the drop attacks.16.3 Vestibular disorders and adverse driving outcomesThe evidence linking vestibular disorders with adverse driving outcomes is weak because therehas been little empirical research in this area. Nonetheless driving ability is dependent on thenormal functioning of the vestibular mechanism to sense movement and position.In subjective studies where drivers with vestibular disorders were asked about driving, drivingdifficulties were commonly reported and included a wide range of difficulties including drivingin the rain, at night, pulling in and out of parking spaces, changing lanes, and freeway and rushhour driving.In one study, 20-40% of drivers reported that they had had to pull off the road while driving dueto vertigo. In a different study, 43% indicated that they had felt dizzy while driving; only 27%indicated that they ‘always’ or ‘usually’ got a warning that a dizzy spell was about to occur, withmore than 1/3 indicating that they ‘rarely’ or ‘never’ get warnings. Of those who did getwarnings, 56% indicated that there was less than a 5-second interval between the warning andthe dizzy spell.16.4 Effect of vestibular disorders on functional ability to driveThe functional effects associated with vestibular disorders can occur suddenly and with sufficientseverity to make safe driving of any type of vehicle impossible.People with vestibular disorders become disoriented more easily by extraneous visual stimuli orvisual noise. This means that drivers are more likely to have difficulty driving in reduced visualconditions such as driving at night or in the rain.Rapid head movements are also likely to elicit vertigo in people with vestibular disorders. Thismeans that tasks such as parking a car, maneuvering in a parking space, lane maintenance andlane changes, and entering traffic may be risk factors for the onset of vertigo.Research also indicates that damage to the vestibular system results in cognitive deficits inpeople with both peripheral and central vestibular disorders. People with vestibular disordersexhibit a range of cognitive deficits including those that are spatial and non-spatial. Thecognitive deficits do not appear to be related to any particular episode of vertigo or dizziness andthe deficits may occur even in those people who have no symptoms of dizziness or posturaldeficits.151