Overnight Sleep Study
A sleep study or polysomnogram (PSG) is a procedure that records and charts numerous physiologic functions during sleep. This includes the measurement of brain waves or EEG by using electrodes placed on the scalp. ECG and heart rate are measured using chest electrode. Breathing parameters measured include chest and abdominal effort, air flow, and blood oxygen saturation. Eye movements and muscle activity help determine the physiologic stage of sleep.. Measurement of limb movement also helps identify disorders such as PLMS.
The recording of the PSG during the night is called nocturnal PSG. Daytime recordings for shift workers may be arranged as well. The PSG is most informative when it is performed during the individual's normal sleep time.
Multiple Sleep Latency Test (MSLT)
This is a standardized test to rule out narcolepsy and/or Hypersomnolence, both are disorders associated with excessive sleepiness during wake hours.
This study consists of a series of four of five nap studies performed during the day following a night study (NPSG). It is preferable in specific instances to allow the individual to wake up spontaneously but in general the first nap usually begins approximately 1.5-2 hours after waking. Naps are scheduled at two hour intervals, and the time it takes to fall asleep is recorded. In between naps the patient has to remain awake and out of bed.
People who have narcolepsy tend to fall asleep at unusual times during the day. The MSLT will measure how fast sleep occurs during the day. It will also show what kind of sleep you have when you take a nap.
A drug screen may be require at the time of the MSLT. There are a number of drugs that can affect the results of the sleep study. The drug screen will help validate the results and ensure the accuracy of the diagnosis.
Maintenance of Wakefulness Test (MWT)
This is a standardized test performed to measure your ability to stay awake and alert. The Maintenance of Wakefulness Test can provide information useful in measuring the success of treatments utilized for sleep disorders that cause excessive daytime sleepiness. MWT may also be used as an adjunct to determinations regarding safety of driving and return to work in hazardous environments.