In a systematic review of published evidence, the United States Preventive Services Task Force in 2017 concluded that there was uncertainty about the accuracy or clinical utility of all potential screening tools for<unk> , and recommended that current evidence is insufficient to assess the balance of benefits and harms of screening for<unk>  in asymptomatic adults. The diagnosis of<unk>  syndrome is made when the patient shows recurrent episodes of partial or complete collapse of the upper airway during sleep resulting in<unk> s or hypopneas, respectively. Criteria defining an<unk>  or a hypopnea vary. The American Academy of Sleep Medicine (AASM) defines an<unk>  as a reduction in airflow of ≥ 90% lasting at least 10 seconds. A hypopnea is defined as a reduction in airflow of ≥ 30% lasting at least 10 seconds and associated with a ≥ 4% decrease in pulse oxygenation, or as a ≥ 30% reduction in airflow lasting at least 10 seconds and associated either with a ≥ 3% decrease in pulse oxygenation or with an arousal. To define the severity of the condition, the<unk> -Hypopnea Index (AHI) or the Respiratory Disturbance Index (RDI) are used. While the AHI measures the mean number of<unk> s and hypopneas per hour of sleep, the RDI adds to this measure the respiratory effort-related arousals (RERAs). The<unk>  syndrome is thus diagnosed if the AHI is > 5 episodes per hour and results in daytime sleepiness and fatigue or when the RDI is ≥ 15 independently of the symptoms. According to the American Association of Sleep Medicine, daytime sleepiness is determined as mild, moderate and severe depending on its impact on social life. Daytime sleepiness can be assessed with the Epworth Sleepiness Scale (ESS), a self-reported questionnaire on the propensity to fall asleep or doze off during daytime. Screening tools for<unk>  itself comprise the STOP questionnaire, the Berlin questionnaire and the STOP-BANG questionnaire which has been reported as being a very powerful tool to detect<unk> . Criteria According to the International Classification of Sleep Disorders, there are 4 types of criteria. The first one concerns sleep – excessive sleepiness, nonrestorative sleep, fatigue or insomnia symptoms. The second and third criteria are about respiration – waking with breath holding, gasping, or choking; snoring, breathing interruptions or both during sleep. The last criterion revolved around medical issues as hypertension, coronary artery disease, stroke, heart failure, atrial fibrillation, type 2 diabetes mellitus, mood disorder or cognitive impairment. Two levels of severity are distinguished, the first one is determined by a polysomnography or home sleep<unk>  test demonstrating 5 or more predominantly<unk>  respiratory events per hour of sleep and the higher levels are determined by 15 or more events. If the events are present less than 5 times per hour, no<unk>  is diagnosed. A considerable night-to-night variability further complicates diagnosis of<unk> . In unclear cases, multiple testing might be required to achieve an accurate diagnosis. Polysomnography AHI Rating 30 Severe Nighttime in-laboratory Level 1 polysomnography (PSG) is the gold standard test for diagnosis. Patients are monitored with EEG leads, pulse oximetry, temperature and pressure sensors to detect nasal and oral airflow, respiratory impedance plethysmography or similar resistance belts around the chest and abdomen to detect motion, an ECG lead, and EMG sensors to detect muscle contraction in the chin, chest, and legs. A hypopnea can be based on one of two criteria. It can either be a reduction in airflow of at least 30% for more than 10 seconds associated with at least 4% oxygen desaturation or a reduction in airflow of at least 30% for more than 10 seconds associated with at least 3% oxygen desaturation or an arousal from sleep on EEG. An "event" can be either an<unk> , characterized by complete cessation of airflow for at least 10 seconds, or a hypopnea in which airflow decreases by 50 percent for 10 seconds or decreases by 30 percent if there is an associated decrease in the oxygen saturation or an arousal from sleep. To grade the severity of sleep<unk> , the number of events per hour is reported as the<unk> -hypopnea index (AHI). An AHI of less than 5 is considered normal. An AHI of 5–15 is mild; 15–30 is moderate, and more than 30 events per hour characterizes severe sleep<unk> . Home oximetry In patients who are at high likelihood of having<unk> , a randomized controlled trial found that home oximetry (a non-invasive method of monitoring blood oxygenation) may be adequate and easier to obtain than formal polysomnography. High probability patients were identified by an Epworth Sleepiness Scale (ESS) score of 10 or greater and a Sleep<unk>  Clinical Score (SACS) of 15 or greater. Home oximetry, however, does not measure<unk> c events or respiratory event-related arousals and thus does not produce an AHI value.
Obstructive sleep apnea
Sleep apnea
Central sleep apnea
Obesity hypoventilation syndrome
Hyperventilation syndrome
Sleep-related breathing disorder
Central hypoventilation syndrome
Reactive airway disease