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Parasomnia
An event happening during sleep, or induced or exacerbated by sleep, such as sleepwalking or asthma; not a dyssomnia.
Paroxysmal nocturnal dyspnea (PND)
Respiratory distress and shortness of breath due to pulmonary edema, appearing suddenly and often awakening the sleeping individual.
Pathological Sleep
Abnormal sleep patterns.
Pavor Nocturnus (Night Terrors)
See Night Terrors.
Perceptual Disengagement
Change in consciousness at the onset of sleep when environmental stimuli are no longer perceived, and there is no longer any conscious, meaningful interaction with the environment.
Periodic Breathing
Repetitive apneic pauses, common in premature infants.
Periodic Limb Movement Disorder
Also known as periodic leg movements and nocturnal myoclonus. Characterized by periodic episodes of repetitive and highly stereotyped limb movements occuring during sleep. The movements are often associated with a partial arousal or awakening; however, the patient is usually unaware of the limb movements or frequent sleep disruption. Between the episodes, the legs are still. There can be marked night-to-night variability in the number of movements or in the existence of movements.
Persistent Insomnia
Continuing insomnia responding poorly to treatment.
Pharynx
Area posterior to the nares and the oral cavity; passageway for air from the nasal cavity and/or the mouth to the lungs via the larynx and the trachea, for food and liquids from the mouth to the esophagus
Phase advance
Movement to a position earlier in the 24 hour sleepwake cycle of a period of sleep or wake; for example, a shift of the sleep phase from 11 p.m.7 a.m. to 8 p.m.4 a.m.
Phase delay
Phase delay is exactly the opposite of phase advance, i.e., a shift later in time.
Phasic (Event/Activity)
Brain, muscle, or autonomic related event of a brief and episodic nature occurring in sleep. Usually occur during REM sleep, such as eye movements and/or muscle twitches
Photoperiod
Duration of light in a light/dark cycle.
Pickwickian Syndrome
Obesity accompanied by somnolence, lethargy, chronic hypoventilation, hypoxia, and secondary polycythemia (a condition marked by an abnormal increase in the number of circulating red blood cells); usually has severe obstructive sleep apnea
Pineal Gland
Gland in the brain secreting the hormone melatonin.
PLMD-Arousal Index
Number of sleep-related periodic leg movements per hour of sleep that are associated with an EEG arousal
PO2
Partial pressure of oxygen (O2) in the blood. A value above 60 is usually considered a safe level: lower than 60 indicated hypoxemia and potential danger for the patient.
Polycyclic
Multiple sleep periods and wake periods in a 24-hour day.
Polysomnogram (PSG)
Continuous and simultaneous recording of physiological variables during sleep, i.e., EEG, EOG, EMG (the three basic stage scoring parameters), EKG, respiratory air flow, respiratory excursion, lower limb movement, and other electrophysiological variables.
Polysomnograph
Biomedical instrument for the measurement of multiple physiological variables of sleep
Polysomnographic Technologist
Health care professional trained in performing diagnostic sleep studies
Post-Prandial Drowsiness
Sleepiness that occurs after a meal, usually lunch
Post-Traumatic Stress Disorder
Re-experiencing of a traumatic event in the form of repetitive dreams, recurrent and intrusive daytime recollections, and/or dissociative flashback episodes.
Premature morning awakening
Early termination of the sleep period in a sleep maintenance DIMS due to inability to return to sleep after the last of several awakenings
Prescribed CPAP Pressure
Pressure(s) or settings determined by a CPAP titration sleep study, which a physician prescribes for a patient's CPAP therapy machine
Pulse Oximetry
Non-invasive measure of oxygen saturation; that is the amount of oxygen saturated in the hemoglobin in terms of percentage; not as accurate as the values obtained from an arterial blood gases (ABG) test and should only be used as a gauge of oxygenation. Normal ranges are between 95-100%.
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