ABSTRACT
Patients with episodic neurological dysfunction form a group of particular interest to clinicians, as well as investigators studying driving performance. Of these, the two general categories that will be discussed in this chapter are sleep disorders and epilepsy. še term epilepsy comprises a number of discrete clinical syndromes that share in common the characteristic of recurrent seizures, which vary in type, severity and frequency of recurrence. Seizures, as de¨ned here, may be thought of as discrete episodes of altered neurological function caused by paroxysmal cortical
electrical discharges. Seizures may a¥ect the entire cortex or just a part of it, and are therefore called either generalized or partial, respectively (International League Against Epilepsy [ILAE], 1981). Generalized seizures are always associated with loss of or alteration in consciousness, while partial seizures may or may not. Partial seizures unaccompanied by altered consciousness are termed simple (i.e., “simple partial seizures”), while those in which consciousness or memory are a¥ected are called complex (i.e., “complex partial seizures”). Epilepsy is a relatively common condition that a¥ects over two million Americans, with about 44 new cases per 100,000 reported annually (Hauser, Annengers,
49.1 Introduction ...........................................................................................................................49-1 49.2 Sleep Disorders .......................................................................................................................49-2
Crash Risk in Sleepy Drivers • Simulators in OSA • Simulators in Narcolepsy 49.3 Epilepsy .................................................................................................................................. 49-6
MVC Risk in Epilepsy • Simulators in Epilepsy 49.4 Challenges and Future Directions ......................................................................................49-7 Key Points ...........................................................................................................................................49-8 Glossary ..............................................................................................................................................49-8 Key Readings ......................................................................................................................................49-8 References ...........................................................................................................................................49-8
Abstract
e Problem. Drivers with sleep disorders, such as obstructive sleep apnea (OSA), have an increased crash risk that can be dif-¨cult to predict in individual drivers. Epileptics may also have an increased risk, although the extent of that risk is not completely de¨ned. Because seizures are intermittent events, and impairment from sleepiness varies based upon a variety of factors, determining crash risk is di¬cult in these patient populations. Role of Driving Simulators. Driving simulators o¥er an opportunity to study drivers with episodic impairment of function due to sleep disorders or seizures in a safe, controlled environment. še addition of divided attention tasks and physiological measures, such as the electroencephalogram (EEG), may enhance the ability to detect dangerous driving behaviors. Key Results of Driving Simulator Studies. Studies with driving simulators show that drivers with OSA and narcolepsy perform worse than those without neurological and sleep disorders, and their performance improves with treatment. Few data are available on drivers with epilepsy, although some preliminary studies have shown deteriorated performance due to medications and EEG-de¨ned “subclinical” seizures. Scenarios and Dependent Variables. Studies of drivers with sleep disorders typically use scenarios that are monotonous, with few obstacles. Some have incorporated tests of divided attention. Standard deviation of lane position (SDLP) is the most frequently used dependent variable to di¥erentiate drivers with sleep disorders from normal controls, although other measures, such as crashes or o¥-road events are also used. Little is known about appropriate scenarios and dependent variables in epileptic drivers. Platform Specicity and Equipment Limitations. All currently available simulators have the scenario development tools and data-recording capabilities required to perform the necessary assessments. However, standardization of these procedures does not exist at present.
