The key diagnostic criteria for obstructive sleep apnoea in adults include a history of symptoms such as snoring, witnessed apnoeas, unrefreshing sleep, waking headaches, unexplained excessive sleepiness, tiredness or fatigue, nocturia, choking during sleep, sleep fragmentation or insomnia, and cognitive dysfunction or memory impairment NICE NG202.
Diagnosis is confirmed through sleep studies, with respiratory polygraphy or polysomnography used to diagnose OSAHS and determine its severity as mild, moderate, or severe based on the results of the sleep study NICE NG202.
Severity assessment involves analyzing the sleep study results, which quantify the number and duration of apnoeic and hypopnoeic episodes, as well as oxygen saturation levels NICE NG202.