Editing Polysomnography (section)

{{short description|Multi-parameter study of sleep and sleep disorders}}
{{distinguish|text=[[Electroencephalography|Electroencephalography (EEG)]], [[Electrocardiography|Electrocardiography (ECG)]], [[Electronystagmography|Electronystagmography (ENG)]], [[Electrooculography|Electrooculography (EOG)]], and [[Electromyography|Electromyography (EMG)]]}}
{{Infobox diagnostic
|  Name        = Polysomnography
|  Image       = Sleep Stage REM.png
|  Caption     = Polysomnographic record of [[Rapid eye movement sleep|REM]] sleep. [[Eye movement (sensory)|Eye movements]] highlighted by red rectangle.
|  ICD10       =
|  ICD9        = {{ICD9proc|89.17}}
|  MeshID      = D017286
|  MedlinePlus = 003932
|  OPS301      = {{OPS301|1-790}}
|  LOINC       = {{LOINC|28633-6}}
|  OtherCodes  =
}}

'''Polysomnography''' ('''PSG''') is a [[parameter|multi-parameter]] type of [[sleep study]]<ref>{{Cite journal|last1=Ibáñez|first1=Vanessa|last2=Silva|first2=Josep|last3=Cauli|first3=Omar|date=2018-05-25|title=A survey on sleep assessment methods|journal=PeerJ|language=en|volume=6|pages=e4849|doi=10.7717/peerj.4849|pmid=29844990|pmc=5971842|issn=2167-8359 |doi-access=free }}</ref> and a diagnostic tool in [[sleep medicine]]. The test result is called a '''polysomnogram''', also abbreviated PSG. The name is derived from [[Greek language|Greek]] and [[Latin language|Latin]] roots: the Greek πολύς (''polus'' for "many, much", indicating many channels), the Latin ''somnus'' ("sleep"), and the Greek γράφειν (''graphein'', "to write").

Type I polysomnography is a sleep study performed overnight with the patient continuously monitored by a credentialed technologist. It records the physiological changes that occur during sleep, usually at night, though some labs can accommodate shift workers and people with [[circadian rhythm sleep disorder]]s who sleep at other times. The PSG monitors many body functions, including [[human brain|brain]] activity ([[Electroencephalography|EEG]]), [[human eye|eye]] movements ([[Electrooculography|EOG]]), muscle activity or [[skeletal muscle]] activation ([[Electromyography|EMG]]), and [[human heart|heart]] rhythm ([[Electrocardiography|ECG]]). After the identification of the [[sleep disorder]] [[sleep apnea]] in the 1970s, breathing functions, [[Respiration (physiology)|respiratory]] airflow, and respiratory effort indicators were added along with peripheral [[pulse oximetry]]. Polysomnography no longer includes [[nocturnal penile tumescence|NPT]] monitoring for [[erectile dysfunction]], as it is reported that all male patients will experience erections during phasic [[REM sleep]], regardless of dream content.

Limited channel polysomnography, or unattended home sleep tests, are called Type II–IV channel polysomnography. Polysomnography should only be performed by technicians and technologists who are specifically accredited in sleep medicine. However, at times nurses and respiratory therapists perform polysomnography without specific knowledge and training in the field.

Polysomnography data can be directly related to [[sleep onset latency]] (SOL), REM-sleep onset latency, number of awakenings during the sleep period, total sleep duration, percentages and durations of every sleep stage, and number of [[arousal]]s. It may also record other information crucial for diagnostics that are not directly linked with sleep, such as movements, respiration, and cardiovascular parameters. In any case, through polysomnographic evaluation, other information (such as body temperature or [[esophagus|esophageal]] [[pH]]) can be obtained according to the patient's or the study's needs.<ref>Orr, W. C. (1985). "Utilization of polysomnography in the assessment of sleep disorders". ''The Medical clinics of North America'', ''69''(6), 1153–1167.</ref>

Video-EEG polysomnography, which combines polysomnography with video recording, has been described as more effective than polysomnography alone for the evaluation of sleep troubles such as [[parasomnia]]s, because it allows easier correlation of EEG and polysomnography with bodily motion.<ref>Aldrich, M. S., & Jahnke, B. (1991). "Diagnostic value of video‐EEG polysomnography". ''Neurology'', ''41''(7), 1060.</ref>