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Ask the Mental Health Expert Archives 2001-2004

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Limb Movement Disorders

Q. I am interested in more information on the Limb Movement Disorders. I sleep on average about 2 hours a night and am exhausted most of the time. I do not nap, drink caffeine and only go to bed when I feel sleepy. I take Mirapex because I have restless legs and it helps some; however, the movement is not limited to just my legs, which seems to be getting worse. Are there any medications, other than what I am taking, that may help me sleep? Can you elaborate on limb movement as a cause of insomnia?

A. Two hours a night, eh? Sounds like you need some more help! Sometimes grouped under the heading, Periodic Limb Movements of Sleep (PLMS) or nocturnal myoclonus, this neuromuscular disorder is an important cause of insomnia and disrupted sleep. PLMS may occur on its own, or as part of Restless Leg Syndrome (RLS).

In the mid-1940s, Swedish neurologist Karl A. Ekbom described a disorder characterized by sensory symptoms and motor disturbance of the limbs, mainly during rest. Ekbom named the condition restless legs syndrome (also called, Ekbom's Syndrome). Although RLS affects about 10% to 15% of the US population, it is often unrecognized and misdiagnosed. It may begin at any age, but most patients who are severely affected are middle-aged or older. [For details, see Evidente & Adler, VOL 105 / NO 3 / MARCH 1999 / POSTGRADUATE MEDICINE].

In 1995, the International Restless Legs Syndrome Study Group developed criteria for diagnosing RLS; namely: (1) a desire to move the limbs, often associated with unpleasant sensations in the legs, such as "pins and needles", "skin crawling", etc.; (2) symptoms are exacerbated by rest and relieved by activity, (3) motor restlessness, and (4) nocturnal worsening of symptoms. About 80% of patients with restless legs syndrome have unilateral or bilateral (one or both legs) periodic limb movements of sleep, also called nocturnal myoclonus.

These movements are stereotyped, repetitive, slow flexions of the limbs (either legs alone, or legs more than arms) during stage 1 or 2 sleep. PLMS occur semi-rhythmically at intervals of 5 to 60 seconds and last about two seconds. In the lower limbs, repetitive turning up of the big toe with fanning of the small toes is seen, along with flexion of the ankles, knees, and thighs.

In all cases of PLMS or RLS, a thorough medical and neurological evaluation is essential. Deficiency of iron, folate, or magnesium may worsen RLS, and appropriate dietary supplements may be helpful (under a physician's supervision!).

Other medical and neurological disorders must also be ruled out. Sometimes, a special overnight recording of sleep and breathing (called a PSG) is helpful in confirming the diagnosis and ensuring that other sleep problems are not also occurring. A variety of medications are used to treat PLMS and RLS, depending on the cause and severity.

Mirapex is one of the "dopamine-type" agents, also used to treat Parkinson's Disease. Other agents that have been useful (for PLMS, RLS, or both) include clonazepam, opioids, gabapentin, and clonidine. The antidepressant bupropion has also been used to treat PLMS. Each of these agents has its pros and cons, risks and benefits.

In your case--since you do not seem to be getting very much relief--I would consider arranging a consultation with a specialist in sleep-related movement disorders. Ideally, this could be in concert with your primary care physician or whoever is now prescribing your Mirapex. I hope your sleep improves soon!

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January 2004

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