The basic step in the diagnostic algorithm in patients with a sleep disorder is to obtain their history, which, in some entities, is often enough to established the diagnosis.Questionnaires (Epworth sleepiness scale, sleep diary, etc.) are employed to clarify or quantify the problem. The basic method of examination is polysomnography or its simplified variant called limited actigraphy.
Approaches used in the differential diagnosis of individual disorders include the multiple sleep latency test (MSLT), maintenance wakefulness test (MWT) or actigraphy. The most common sleep disorders are insomnia, obstructive sleep apnoe, restless leg syndrome and narcolepsy.