This chapter focuses on traffic fatalities and injuries as a public health problem and driver sleepiness involvement in crashes. It explains how physiology and behavior change during sleepy driving and what is the precipitating cause of the impaired behavior involved in a crash. Considering the central role of sleepiness in crash causation, knowledge of the use of countermeasures is an important issue. Apart from driver-initiated countermeasures one may also consider various types of information to the driver about fatigue risks in driving. In order to reduce driver sleepiness, a holistic approach may be a promising strategy that takes technological, organizational and individual factors into account. Evidence-based fatigue management programs are a key factor in this approach and should reassure that professional drivers have the rosters, tools and knowledge to maintain high alertness and safe driving.

The legal consequences of excessive sleepiness may impact patients, their physicians, and the public at large. Individuals with daytime sleepiness and/or known or suspected sleep disorders need to take precautions at work or when driving to ensure that they do not pose a risk to themselves or others. Physicians should inquire about excessive sleepiness or other symptoms of sleep apnea in any patient who drives, but especially in patients who are commercial vehicle drivers. Physicians and healthcare workers need to be aware of the accident risks associated with sleep disorders and the legal implications around this in their particular jurisdiction. The development of new guidelines and medical standards in the transportation industry will eventually have an impact on physicians, employers and drivers alike. Legislators must continue to work with practitioners and scientists to balance adequate protection of the public interest with individual rights.

Restless legs syndrome and periodic limb movement disorder are common neurological entities that may be associated with insomnia and excessive daytime sleepiness. This chapter reviews the clinical features, natural history, laboratory investigations, genetics, pathology, and management of primary restless legs syndrome (RLS) and periodic limb movement disorder (PLMD). Large epidemiological surveys have shown that self-reported symptoms of RLS were correlated with sleepiness. Electrodiagnostic testing with nerve conduction studies and electromyography are useful to detect subtle peripheral neuropathies. Several factors suggest that impaired dopaminergic function and iron homeostasis underlie the pathophysiology of RLS. One study demonstrated that dopaminergic treatment of RLS patients improved both RLS severity and sleepiness as measured by multiple sleep latency test (MSLT) score. Considerable research has been directed towards elucidating the basic mechanisms and optimizing the management of RLS and PLMD.

The evaluation of a patient with excessive sleepiness requires that a detailed sleep history is taken with medical, psychiatric, and psychosocial factors considered, and a differential diagnosis developed. This chapter deals with the important elements in the clinical evaluation of patients with excessive sleepiness. The social history should be elicited, particularly relationships with other family members, and including determination of any financial, personal or social stresses that may contribute to sleep disturbance. Some sleep disorders including sleep apnea syndrome, narcolepsy, recurrent hypersomnia as well as restless legs syndrome, have a familial tendency. The physical examination ideally should be comprehensive and focus on respiratory, cardiovascular, gastrointestinal, endocrine and neurological evaluation. The patient who is sleepy may be asked to complete various tests of performance, such as a psychomotor vigilance test (PVT), or other tests of cognitive ability.

This chapter presents a summary of excessive sleepiness definitions used in epidemiological studies. Studying prevalence, incidence and risk factors for excessive daytime sleepiness bears little impact on the development of new treatments for this symptom. Three sleep disorders are characterized by excessive sleepiness and are divided into 12 diagnoses: hypersomnia, behaviorally induced insufficient sleep syndrome, and narcolepsy. Hypersomnia and behaviorally induced insufficient sleep syndrome are virtually undocumented in the general population. Excessive sleepiness can be caused by various factors such as poor sleep hygiene, work conditions, and psychotropic medication use. Excessive sleepiness has been found to be associated also with sleep-disordered breathing, psychiatric disorders, especially depression, and physical illnesses. Excessive sleep quantity is an associated symptom in depressive disorders in the DSM-IV classification. Several clinical studies have also pointed out the high occurrence of subjective excessive sleepiness in association with mental disorders, organic disorders, or both.