<unk>  <unk> , a type of sleep study, is a multi-parameter study of sleep and a diagnostic tool in sleep medicine. The test result is called a polysomnogram, also abbreviated<unk> . The name is derived from Greek and 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<unk>  is a sleep study performed overnight while being 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 disorders who sleep at other times. The<unk>  monitors many body functions, including brain activity (EEG), eye movements (EOG), muscle activity or skeletal muscle activation (EMG), and heart rhythm (ECG)1. After the identification of the sleep disorder sleep apnea in the 1970s, the breathing functions, respiratory airflow, and respiratory effort indicators were added along with peripheral pulse oximetry.<unk>  no longer includes 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<unk> , or unattended home sleep tests, is called Type II – IV channel<unk> . With some controversy,<unk>  is best performed by technicians and technologists who are specifically accredited in sleep medicine. However, at times nurses and respiratory therapists perform<unk>  without specific knowledge and training in the field.<unk>  data can be directly related to sleep onset latency (SOL), REM-sleep onset latency, the number of awakenings during the sleep period, the total sleep duration, percentages and durations of every sleep stage, and the number of arousals. But there can also be other information crucial for diagnostics, that are not directly linked with sleep, such as movements, respiration, and cardiovascular parameters. In any case, through<unk> c evaluation, other information can be obtained (such as body temperature or esophageal pH) according to the patient's or the study's needs. Video-EEG<unk>  which combines<unk>  with video recording has been described as more effective than only<unk>  for the evaluation of sleep troubles such as parasomnias, because it allows easier correlation of EEG and<unk>  with bodily motion.
Polysomnography
Somnology
Sleep study
Magnetoencephalography
Hypnogram
Electroencephalography
Audiometry
Echoencephalography