Restless Legs Syndrome and Related Disorders - Diagnosis

Polysomnography

Overnight polysomnography involves a number of tests to measure different functions during sleep. It is typically performed in a sleep center and may be performed to rule out sleep apnea or to confirm the effectiveness of RLS treatments.

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The patient arrives about two hours before bedtime without having made any changes in daily habits. Polysomnography electronically monitors the patient as he or she passes, or fails to pass, through the various sleep stages. Polysomnography tracks the following:

Brain waves.
Body movements.
Breathing.
Heart rate. One study suggested that many patients with obstructive sleep apnea display distinctive heart rhythms as detected by electrocardiogram (ECG).
Eye movements.

Changes in breathing and the levels of oxygen in the blood are also recorded. In patients with suspected sleep apnea, the sleep expert will track instances of apnea and hypopnea that last longer than 10 seconds. In general, if there are more than five episodes per hour, apnea is significant and if there are more than 15, the condition is serious.

Overnight polysomnography has been the gold standard for diagnosing obstructive sleep apnea in both adults and children. It is very labor intensive and expensive, however, and also misses snoring-induced arousals. A full set of tests including a night at a sleep clinic may cost $2,000 to $3,000 and is not always covered by insurance. In addition, some centers have waiting lists that can be months long.

Actigraphy

Actigraphy uses a small wristwatch-like device (e.g., Actiwatch) to monitor sleep quality in people with suspected RLS, periodic limb movement disorder (PLMD), insomnia, sleep apnea, and other sleep-related conditions. The device can be applied to the wrists or ankles. It measures muscle movements and records them during sleep. For example, with PLMD, it can provide information on total duration of movements, the number of occurrences, whether PLMD occurs simultaneously in both legs, and the effects on sleep.

It is not as accurate as polygraphy because it cannot measure all the biologic effects of sleep. It is more accurate than a sleep log, however, and very helpful for recording long periods of sleep.

Sleepiness Scale

The Epworth sleepiness scale uses a simple questionnaire to measure excessive sleepiness during eight situations.

THE EPWORTH SLEEPINESS SCALE
SITUATION	CHANCE OF DOZING
Sitting and reading.	(Indicate a score of 0 to 3) 0 = no chance of dozing 1 = slight chance of dozing 2 = moderate chance of dozing 3 = high chance of dozing
Watching TV.	(Indicate a score of 0 to 3) 0 = no chance of dozing 1 = slight chance of dozing 2 = moderate chance of dozing 3 = high chance of dozing
Sitting inactive in a public place (e.g., a theater or a meeting).	(Indicate a score of 0 to 3) 0 = no chance of dozing 1 = slight chance of dozing 2 = moderate chance of dozing 3 = high chance of dozing
Riding as a passenger in a car for an hour without a break.	(Indicate a score of 0 to 3) 0 = no chance of dozing 1 = slight chance of dozing 2 = moderate chance of dozing 3 = high chance of dozing
Lying down to rest in the afternoon when circumstances permit.	(Indicate a score of 0 to 3) 0 = no chance of dozing 1 = slight chance of dozing 2 = moderate chance of dozing 3 = high chance of dozing
Sitting and talking to someone	(Indicate a score of 0 to 3) 0 = no chance of dozing 1 = slight chance of dozing 2 = moderate chance of dozing 3 = high chance of dozing
Sitting quietly after a lunch without alcohol.	(Indicate a score of 0 to 3) 0 = no chance of dozing 1 = slight chance of dozing 2 = moderate chance of dozing 3 = high chance of dozing
Sitting in a car while stopped for a few minutes in traffic.	(Indicate a score of 0 to 3) 0 = no chance of dozing 1 = slight chance of dozing 2 = moderate chance of dozing 3 = high chance of dozing
Score Results 1-6: Getting enough sleep. 4-8: Tends to be sleepy but is average. 9 and over: Very sleepy and suggestive of sleep-disordered breathing. Patient should seek medical advice.