Sleep disorders may be associated with a variety of clinical symptoms that must be accurately assessed by the physician and the sleep technologist. These disorders must be differentiated from other states of altered physiological status, including normal sleep. This discussion of sleep disorders begins with a review of the eight major classifications of sleep disorders.
The field of clinical sleep medicine includes disorders that were previously in the domain of psychiatry, pulmonology, neurology, pediatrics, cardiology, and internal medicine. The International Classification of Sleep Disorders was published by a committee of the AASM in 1990, and then revised in 1997. The International Classification of Sleep Disorders Diagnostic and Coding Manual, 2d ed. (ICSD-2), published in 2005, is the current comprehensive guide to classification of sleep disorders. As research has expanded knowledge surrounding sleep disorders and the field has become recognized in its own right, classifications have been revised, and work continues to integrate the sleep disorders into the current mainstream coding manuals for medical disorders, the ICD-9 and ICD-10.
The ICSD-2 sorts sleep disorders into eight categories:
- Insomnias
- Sleep Related Breathing Disorders
- Hypersomnias of Central Origin Not Due to a Circadian Rhythm Sleep Disorder, Sleep Related Breathing Disorder or Other Cause of Disturbed Nocturnal Sleep
- Circadian Rhythm Sleep Disorders
- Parasomnias
- Sleep Related Movement Disorders
- Isolated Symptoms, Apparently Normal Variants, and Unresolved Issues
- Other Sleep Disorders
Each category lists the specific sleep disorders that belong to that classification. For each disorder, the manual identifies the essential and associated features of the disorder and provides PSG findings and diagnostic criteria.
Sleep disorders specialists and sleep laboratories use ICSD-2 for correct coding of sleep problems, but we use a second classification on reports and bills to insurers. Insurance companies use the International Classification of Diseases 9 - Clinical Modification (ICD-9-CM) to code medical problems including sleep disorders. The ICD is updated annually by national and international organizations; the next version, ICD-10, already has been adopted in most of the world outside the United States. The AASM provides a crosswalk between the sleep disorders listed in the ICSD-2 and the ICD-9-CM.