AVAILABLE SLEEP STUDIES
Download: Referral for Sleep Test.doc
Polysomnography (sleep test)
Polysomnography monitors several functions of the body relevant to sleep, including brain activity, eye movements, breathing, movement, heart rate, and oxygenation. For this study, a technician will attach electrodes to your head with a glue-like substance known as collodion. Additional electrodes will be attached to the area around your eyes, on your cheeks, chest and legs. Two bands will be placed around your chest and abdomen to monitor respirations while you sleep. The wires from the electrodes will be inserted into a box which will be placed at the head of our bed during the night. There is also a video recording of your sleep so that the doctor and technologist can observe for movements and possible sleep disorders. You will have plenty of freedom to move about in the bed as you normally do during your sleep at home. If you need assistance during the night (e.g., to go to the bathroom) you will be able to signal the technologist to come help you.
Measuring these things while you sleep allows the physician to determine the characteristics of your sleep, including the overall pattern, depth, and amount. It also looks for common sleep disorders.
Throughout the night your brain waves (EEG), respirations, heart rate, movements and other physiological measurements will be monitored continuously and recorded to a computer system for further analysis after your study is completed. Additionally, you will be monitored by video and audio instruments as well.
Multiple Sleep Latency Testing (MSLT)
Multiple sleep latency testing is a way to measure your sleepiness and tendency to fall asleep during the day. It is particularly important in the evaluation of possible narcolepsy. The test is similar to polysomnography, except that it requires fewer monitors (only electrodes on your head, chin, and eyes; breathing and leg movements are not usually measured).
The MSLT consists of four to five "nap opportunities", each two hours apart. The test almost always follows an overnight recording with polysomnography as the previous night's sleep is essential in interpreting the MSLT. About two hours after awakening, you will be asked to lie down and try to sleep. The room will be quiet, and the lights off. After 20-30 minutes, the technologist will wake you up. This will be repeated every 2 hours during the day. For this test, you should bring reading material or work to keep yourself occupied between tests.
Video-EEG monitoring is useful in diagnosing unusual events or activities during the night, especially when these might be seizures. For example, people with known seizure disorders may have behavioral changes during sleep that are not clear to their physician and may be seizures, or other behaviors could be occurring that could be seizures, a sleep disorder, or normal sleep (such as vivid nightmares). Video-EEG monitoring can be performed independently or in conjunction with polysomnography. The test consists of more electrodes on the scalp than for polysomnography, as it looks in much more detail at brain activity.