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Sleep Disorders

Periodic Limb Movement Disorder

01/02/2008

Question:

Is there a correlation between PLMD and sleep apnea and would a sleep lab evaluation be benificial. My husband has been on klonopen with only some improvement. He also, at times snores. A friend was diagnosed with sleep apnea after his evaluation at a sleep lab for excessive snoring. He was also told his legs moved more than usual. now that he wears the sleep mask, he no longer has the leg movements. I appreciate your help. "A sleepless bed-mate"

Answer:

Periodic limb movement disorder (PLMD) is a type of parasomnia. Parasomnias are unwanted events that occur during sleep or during the transition between sleep and wakefulness. In the case of PLMD, the unwanted behavior is excessive limb movements. The limbs that move can be arms, legs or a combination. The movements are not bothersome to the person themselves because they are only aware of them through bed partner's complaints like: "Will you stop kicking me at night?"

PLMD can only diagnosed by a sleep study. Since your husband is on Klonopin, it's my assumption that he is being treated rather for restless legs syndrome (RLS). RLS is different from PLMD. RLS is a disorder of arousal, which occurs during wakefulness and therefore bothers the person who has it and not the bed partner. RLS causes insomnia through an urge to move the legs. Even though RLS and PLMD are two different conditions they often coexist. The reason for this association is not known.

Your email asks an important question regarding the association between sleep apnea and PLMD. The short answer is: we don't know. We do know that sleep apnea causes sleep restriction. Sleep restriction may increase the number of periodic limb movements and may worsen restless legs symptoms. There is evidence that the severity of RLS shows a favorable response to nasal continuous positive airway pressure (CPAP) in the group of patients with obstructive sleep apnea and RLS. The reasons are not well understood. CPAP has not been used as a treatment for RLS or PLMD in patients without any concurrent sleep apnea.

The usual symptoms of sleep apnea include loud snoring, witnessed apneas, restless sleep, gagging and choking during sleep, excessive daytime sleepiness, un-refreshing sleep and waking up with headache and with dry mouth. Also, it is more likely for someone to have sleep apnea if they are overweight or if they have high blood pressure. If your husband is at risk for sleep apnea, it is advisable that he gets a sleep study in order to evaluate his breathing during sleep. If he happens to have sleep apnea and is prescribed CPAP, then watch for a change in his leg movements. It may help.

If you would like additional information regarding sleep and sleep disorders, you can obtain it on the American Academy of Sleep Medicine website. This website also contains a list of Sleep Centers across the country so you can locate one near you if need it. Good luck, and sleep well.

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Response by:

Ziad  Shaman, MD Ziad Shaman, MD
Assistant Professor of Medicine
School of Medicine
Case Western Reserve University