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Movement Disorders

Periodic Limb Movement Disorder

Periodic limb movement disorder (also called sleep myoclonus) is characterised by recurrent brief jerks, which usually involve the ankles and the knees. Similar muscle jerks can involve the arms. These brief rapid movements occur when the patient is asleep and is usually unaware of them. However, they are often associated with awakening from sleep. The patient can wake up completely or simply lighten up his/her sleep. The jerks can involve one or both legs at the same time. The number of jerks is variable and can change from one night to another. However, there are people who can have up to 100 or more jerks each hour. Periodic limb movement disorder may cause difficulty falling asleep, as well as difficulty staying asleep. In some people this can result in daytime sleepiness.

This condition is typical of middle age and elderly people and is rarely seen in children.

Restless Legs

Restless legs refers to an unpleasant sensation usually localised in the calves. It is often described as cramps, soreness, a creeping sensation involving the leg below the knee. It is felt when awake and usually around bedtime. The feelings are such that the person has the need (sometimes the compulsion) to move the legs to get relief and sometimes needs to walk around the room. Restless legs prevent the person from falling asleep.

The severity of the symptoms varies from a mild discomfort to very severe sensation, which can prevent the person from falling asleep. The majority of people with restless legs do have periodic limb movement disorder.

Causes and Predisposing factors

There is no known cause for periodic limb movement disorder, however, it is seen frequently in people with renal failure, iron deficiency and during pregnancy. It is also common in people who use medication such as antidepressants and in people who are withdrawing from medications such as anticonvulsants, benzodiazepines (valium) and other sleep tablets. In approximately 1 in 3 there is a family history of this disorder. The diagnosis of periodic limb movement disorder is obtained by overnight sleep study.

Treatment of Periodic Limb Movement Disorder and Restless Legs

Because the cause of periodic limb movement disorder and restless legs is not known the treatment is symptomatic only. Simple measures may be helpful (avoidance of coffee, tea, alcohol and nicotine). Correction of medical disorders may bring about improvement (diabetes, iron deficiency, and avoidance of antidepressant medications).

When severe enough it requires the use of medication. The treatment may involve the use of benzodiazepine (medication similar to valium), codeine phosphate, morphine and methadone in the more severe cases. Recently medication used for Parkinson's disease has also been used with good results in some people. The response to one medication or another varies among people.

REM Sleep Behaviour Disorder
(acting out dreams)

In this condition patients can have violent behaviour during sleep which can lead to injury to the person or their bed partner. The patient can punch, kick, leap out of bed, even run from the bed during an attempted enactment of dreams. This behaviour during sleep can occur occasionally or up to 3 or 4 times per night on consecutive nights. This condition can start at any age but is most common in adults. It is more common in males than females.

Causes and Predisposing Factors

In the majority of cases there is no obvious reason for this condition. Occasionally it can occur following withdrawal from alcohol and sedatives as well as anti-depressant medications. Sometimes this condition is associated with neurological abnormalities such as dementia and previous stroke.

Complications

REM behaviour disorder can cause injury to the patient or bed partner. This can lead to social consequences, particularly involving the relationship with the bed partner.

Treatment

If the abnormal behaviour occurs frequently treatment may be needed. A medication called clonazepam (in the same group as valium) can be used and is usually effective. Other short acting benzodiazepine such as temazepam are also effective.

Sleep Drunkenness

Sleep drunkenness can be confused with REM behaviour disorder. During sleep drunkenness the patients tends to perform complex activity in a state between sleep and wakefulness. The person can usually wake up through the night and can perform complex tasks such as making telephone calls and go back to sleep with no recollection of what happened. In sleep drunkenness it is unusual for the person to be injured.

Sleep Epilepsy

Epilepsy can occur during sleep. In some form of epilepsy the patient can have complex behaviour similar to sleep walking. A sleep study may help clarify if sleep epilepsy is present.

Sleep Starts

This refers to sudden jerks, which occur at the beginning of sleep. This should be considered normal as it occurs in approximately 60-70% of the population. Severe increased exertion, emotion stress and an increase in the intake of caffeine can increase the frequency of sleep starts. In sleep starts the jerks may involve the arms, legs or the entire body. Sometimes the person has the feeling of falling or imbalance. Treatment is not usually needed.