Editing Sleep apnea (section)

=== Polysomnography ===
{| class="wikitable" align="right"
![[Apnea-hypopnea index|AHI]]
!Rating
|-
|< 5
|Normal
|-
|5–15
|Mild
|-
|15–30
|Moderate
|-
|> 30
|Severe
|}<!--Deleted image removed: [[File:Apnea2Min.jpg|thumb|200px|right|Two minute epoch representing continuous OSA. Click on this image for larger version.]]-->
Nighttime in-laboratory Level 1 polysomnography (PSG) is the gold standard test for diagnosis. Patients are monitored with [[Electroencephalography|EEG]] leads, [[pulse oximetry]], temperature and pressure sensors to detect nasal and oral airflow, respiratory impedance [[Plethysmograph|plethysmography]] or similar resistance belts around the chest and abdomen to detect motion, an [[Electrocardiography|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.<ref name="stats2">{{cite journal |author=Slowik |first=Jennifer M. |author2=Collen |first2=Jacob F. |date=2020 |title=Obstructive Sleep Apnea |journal=StatPearls |pmid=29083619}} {{CC-notice|cc=by4|url=https://www.ncbi.nlm.nih.gov/books/NBK459252/}}</ref>

An "event" can be either an apnea, 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.<ref>{{cite journal |date=August 1999 |title=Sleep-related breathing disorders in adults: recommendations for syndrome definition and measurement techniques in clinical research. The Report of an American Academy of Sleep Medicine Task Force |journal=Sleep |volume=22 |issue=5 |pages=667–689 |doi=10.1093/sleep/22.5.667 |pmid=10450601 |doi-access=free}}</ref> To grade the severity of sleep apnea, the number of events per hour is reported as the [[apnea-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 apnea.