Polysomnography (PSG) and Multiple Sleep Latency Test (MSLT)
The PSG continuously records normal and abnormal physiologic activity during an entire night. A typical PSG montage includes an electroencephalogram (EEG), electrooculogram, electromyogram, electrocardiogram, and continuous pulse oximetry and includes measurement of airflow, respiratory effort, and leg movements. It documents the adequacy of sleep, including the frequency, duration, and total amounts of stages 1, 2, 3 and 4 (slow-wave sleep), and REM sleep. It also identifies whether other sleep pathologies, such as obstructive sleep apnea, are present.
The MSLT is the primary test for the diagnosis of narcolepsy. This test assesses 2 major components of narcolepsy: hypersomnolence and SOREMPs (Sleep Onset Rapid Eye Movement Periods), which occur in narcolepsy but are otherwise uncommon. The mean sleep latency, or time to sleep onset, provides evidence for hypersomnolence. The test uses an EEG to record sleep onset during normal waking hours. It consists of 4 or 5 20-minute nap opportunities at 2-hour intervals. Normally, sleep latency is greater than 10 minutes and REM sleep does not occur at sleep onset. Patients with narcolepsy typically fall asleep in 5 minutes or less and will display SOREMPs during at least 2 of the 5 daytime nap periods.
Warnings and Precautions
Abuse and Misuse
XYREM is a Schedule III controlled substance. The active ingredient of XYREM, sodium oxybate or gamma hydroxybutyrate (GHB), is a Schedule I controlled substance. Abuse of illicit GHB, either alone or in combination with other CNS depressants, is associated with CNS adverse reactions, including seizure, respiratory depression, decreases in the level of consciousness, coma, and death. The rapid onset of sedation, coupled with the amnestic features of XYREM, particularly when combined with alcohol, has proven to be dangerous for the voluntary and involuntary user (eg, assault victim). Physicians should carefully evaluate patients for a history of drug abuse and follow such patients closely.
To report an adverse event please call: 1-800-520-5568
- ^ Carskadon M, Rechtschaffen A. Monitoring and staging human sleep. In: Kryger MH, Roth T, Dement WC, eds. Principles and Practice of Sleep Medicine. 3rd ed. Philadelphia: WB Saunders; 2000:1197-1215.
- ^ Guilleminault C, Angela A. Narcolepsy. In: Kryger MH, Roth T, Dement WC, eds. Principles and Practice of Sleep Medicine. 3rd ed. Philadelphia, Pa: Elsevier; 2000:676–686.
- ^ Mitler MM, Carskadon MA, Hirshkowitz M. Evaluating Sleepiness. In: Kryger MH, Roth T, Dement WC, eds. Principles and Practice of Sleep Medicine. 4th ed. Philadelphia, Pa: Elsevier; 2005:1417–1423..
- ^ Carskadon MA, Dement WC. Normal human sleep: an overview. In: Kryger MH, Roth T, Dement WC, eds. Principles and Practice of Sleep Medicine. 3rd ed. Philadelphia, Pa: Elsevier; 2005:15–25.
- ^ American Academy of Sleep Medicine. The International Classification of Sleep Disorders, Revised: Diagnostic and Coding Manual. Westchester, Ill: American Academy of Sleep Medicine; 2nd edition, 2005