Daytime sleepiness and cataplexy as main symptoms in narcolepsy may account for motor vehicle accidents. Several studies in various countries revealed increased accident rates in narcoleptic patients. Legal restrictions concerning driving licenses have been issued for NP. Physicians are frequently asked for expert opinion about the qualification of NP to drive cars. They have to respect study results and neuropsychological investigations. A questionnaire regarding driving performance was handed out to the members of the German Narcolepsy Society at their 1999 annual conference, in order to obtain data regarding automobile accidents of narcoleptic patients in Germany. 84 patients (41 women, 48.6 ± 15.7 years old, 43 men, 50.4 ± 16.7 years old) and 95 controls (47 women, 37.5 ± 10.8 years old, 48 men, 41.5 ± 11.9 years old) took part. 10 patients had no driving license. 59.2 % stated their accidents due to sleepiness. Compared to controls accident rate per year was significantly increased in patients younger than 40 years. Narcoleptic patients aged above 40 had significant reduced number of accidents with no difference to healthy controls. In order to avoid crashes patients developed various coping strategies (e. g. preparation for driving by taking a nap before driving or taking medication [45 out of 80], stop over to take a nap [41 out of 80]). In a second study neuropsychological tests and driving simulator performance in 22 narcoleptic patients (40.2 ± 13.4 years old) were compared to 10 controls (55.1 ± 7.8 years). There was a significant difference regarding vigilance and alertness. Accident rates in the driving simulator were significantly raised in patients (p < 0.01). Concentration faults in this task were not raised, however. Test results showed wide interindividual variability. Narcoleptic patients have attention deficits over long space of time. When patients have been informed about their disease they can decrease their accident risk by learning coping strategies. If narcoleptic patients have an accident they should get a driving ban for one year. In expert opinions regarding driving licence a standard interview and neuropsychological tests for individual follow-up are necessary. In certain cases a driving simulator test and on-road evaluation should follow. Physicians giving expert opinions should possess qualification in traffic medicine and sleep medicine. (Author/publisher)
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