Download the Patient Guide for a Sleep Study

Overnight Sleep Study (Polysomnogram)

The overnight polysomnogram (PSG) is used to help pinpoint the cause of excessive daytime sleepiness and to diagnose some sleep disorders such as sleep apnea and restless legs syndrome. In most cases, you will be asked to come to the lab about 9:00 p.m.. It will take the technologist about an hour to prepare you for the procedure. This is a simple process of attaching electrodes using a removable cream/gel and tape. The electrodes do not pierce the skin. In the morning, you will be able to leave from a night study in time for your usual daily activities.

You can read or watch television until you are ready to go to bed. At that time, the technologist will connect you to recording equipment. There is a control area, separate from each bedroom, where the technologist monitors the procedure.

The technologist will do all she or he can to make your stay a pleasant one. Do not be afraid to ask questions. A staff member will have two or three patient to look after. You will have private rooms with a bathroom close by. If you have to go to the toilet during the night, just ring for the technologist who will disconnect you from the recording equipment. Cameras may be used to observe your sleep.

Daytime Sleep Study

The daytime sleep study is usually given immediately after an overnight study while the patient is still connected to the electrodes. If you are staying for a day study, you will not be allowed any caffeine. If you get headaches from caffeine withdrawal, discuss this with your doctor. Ask about arrangements for meals. If you are on a special diet and meals are provided, be sure to let the lab know in advance. The day study is usually finished around 5:00 p.m.. However, if you have to stay for a fifth nap, it will be closer to 7:00 p.m.

There are 2 types of Daytime Sleep Studies:

Multiple Sleep Latency Test (MSLT)

You will have at least four, 20 minute nap opportunities during the day to determine the severity of sleepiness and the onset of the dream state during sleep. The latter is used to diagnose a sleep disorder called narcolepsy, along with the overnight study.

Maintenance of Wakefulness Test (MWT)

You will be seated in a darkened room and will be requested to stay awake for 30 minute time periods. This will occur every two hours, four times during the day. This test measures your ability to remain awake.