Investigations at The Department of Sleep Medicine
There are several types of sleep study conducted in the Department.
Home Sleep Study
People whose symptoms suggest they could have obstructive sleep apnoea have a limited study that can be performed in their own home. It involves a demonstration and fitting appointment in the Dept. and then the equipment is worn overnight at home and returned the next day. It involves bands around the chest and abdomen to measure breathing, a small sensor in the nostrils, an oxygen monitor on the finger and electrodes on your legs. This test can diagnose different types of breathing difficulties and assess their severity allowing the correct choice of treatment to be made. Sometimes this limited sleep study does not provide an answer and a more sophisticated sleep study called a Polysomnography is required.
Polysomnography (PSG)
A PSG uses electrodes attached to your scalp and face to record your brain waves (electroencephalography or EEG) and other vital signs overnight to tell us how well you sleep. You will also wear bands around your chest and abdomen to record your breathing, an oxygen monitor on your finger and electrodes on your legs and/or arms to pick up any limb movements. Your night will be recorded on video so that any unusual behaviours can be captured. This test can detect whether your sleep is being disrupted by breathing or limb movements or may simply confirm that you sleep well overnight.
Daytime Sleep Tests
You may stay in the dept. the day after your PSG for a daytime sleep test. There a two types of these the Multiple Sleep Latency Test (MSLT) and Maintenance of Wakefullness Test (MWT), for both of these tests you will keep the scalp and face electrodes on during the day so we can record your sleep. During the MSLT you will be asked to nap in a darkened room for 20 minutes at 2 hour intervals. This test is used to assess your level of sleepiness and whether you go into dreaming (REM) sleep which can be a feature of Narcolepsy. The MWT is a test of your ability to stay awake as you are asked to stay awake for 40 minutes in a semi-darkened room at 2 hour intervals. This test can be used a part of a fitness to drive assessment.
Actigraphy
Actigraphy involves wearing a movement monitor, resembling a fitbit, on your wrist for a few days and nights at home. This is used to assess sleep regularity. Actigraphy equipment is collected from the dept or in the case of patients who live a significant distance from Edinburgh can be posted to a person’s home with straightforward instructions. All patients who are booked in for a PSG study and MSLT will be required to wear an Actiwatch the week prior to coming in.
