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Periodic Limb Movement Disorder

Periodic limb movement disorder (PLMD) and restless leg syndrome (RLS) are distinct disorders, but often occur simultaneously. Both PLMD and RLS are also called (nocturnal) myoclonus, which describes frequent or involuntary muscle spasms. Periodic limb movement was formally described first in the 1950s, and, by the 1970s, it was listed as a potential cause of insomnia. In addition to producing similar symptoms, PLMD and RLS are treated similarly.

Symptoms of PLMD

Periodic limb movement disorder affects people only during sleep. Many patients who suffer from excessive daytime sleepiness do not know they are being aroused from sleep by periodic limb movements because they do not actually wake up. Rather, they will feel as though they have not slept well. These arousals can occur anywhere from five times an hour up to more than 50 times an hour, depending on the severity of movement.

Characterised by behavior ranging from shallow, continual movement of the ankle or toes, to wild and strenuous kicking and flailing of the legs and arms.

Limb movements can be severe enough to wake an individual from sleep, making it difficult to stay asleep for a significant duration and leading to excessive daytime sleepiness.

PLMD may be completely asymptomatic, or they may complain of either excessive daytime sleepiness or insomnia, or both.

Prevalence of PLMS

The incidence of PLMD increases with age. It is estimated to occur in 5% of people age 30 to 50 and in 44% of people over the age of 65. As many as 12.2% of patients suffering from insomnia and 3.5% of patients suffering from excessive daytime sleepiness may experience PLMD.

Treatment

Generally, there are three classes of drugs that are used to treat PLMD. These are benzodiazepines, Parkinson drugs, and narcotics. Medical treatment of PLMD often significantly reduces or eliminates the symptoms of this disorder, though not always. There is no cure for PLMD, and medical treatment must be continued to provide potential relief.

Clonazepam is the most commonly employed benzodiazepine treatment. It is effective in many cases, but not all, and it usually causes drowsiness or sedation. Sometimes, clonazepam allows the patient a better, more restful night’s sleep without affecting the occurrence of limb movement. Patients with PLMD may have other sleep disorders, such as obstructive sleep apnea, which the use of clonazepam could worsen.
The drugs used to treat Parkinson’s disease are also very effective against PLMD. These include, L-dopa/carbidopa, bromocriptine (which suppresses the excretion of prolactin), pergolide, and selegiline. If either benzodiazepines or Parkinson’s medications do not relieve symptoms, then narcotics, such as codeine, oxycodone, methadone, and propoxyphene are sometimes employed.

The causes of PLMD are unknown. The vast majority of PLMD cases occur independently of other disease processes. It is certain that these conditions often cause insomnia, and some research shows that they might also be caused by other sleep disturbances.

Periodic limb movement disorder (PLMD) and restless leg syndrome (RLS) are distinct disorders, but often occur simultaneously. Both PLMD and RLS are also called (nocturnal) myoclonus, which describes frequent or involuntary muscle spasms. Periodic limb movement was formally described first in the 1950s, and, by the 1970s, it was listed as a potential cause of insomnia. In addition to producing similar symptoms, PLMD and RLS are treated similarly.

Periodic limb movement disorder affects people only during sleep. Many patients who suffer from excessive daytime sleepiness do not know they are being aroused from sleep by periodic limb movements because they do not actually wake up. Rather, they will feel as though they have not slept well. These arousals can occur anywhere from five times an hour up to more than 50 times an hour, depending on the severity of movement.

  • Characterised by behavior ranging from shallow, continual movement of the ankle or toes, to wild and strenuous kicking and flailing of the legs and arms.
  • Limb movements can be severe enough to wake an individual from sleep, making it difficult to stay asleep for a significant duration and leading to excessive daytime sleepiness.
  • PLMD may be completely asymptomatic, or they may complain of either excessive daytime sleepiness or insomnia, or both.Prevalence of PLMSThe incidence of PLMD increases with age. It is estimated to occur in 5% of people age 30 to 50 and in 44% of people over the age of 65. As many as 12.2% of patients suffering from insomnia and 3.5% of patients suffering from excessive daytime sleepiness may experience PLMD.Treatment

    Generally, there are three classes of drugs that are used to treat PLMD. These are benzodiazepines, Parkinson drugs, and narcotics. Medical treatment of PLMD often significantly reduces or eliminates the symptoms of this disorder, though not always. There is no cure for PLMD, and medical treatment must be continued to provide potential relief.

    Clonazepam is the most commonly employed benzodiazepine treatment. It is effective in many cases, but not all, and it usually causes drowsiness or sedation. Sometimes, clonazepam allows the patient a better, more restful night’s sleep without affecting the occurrence of limb movement. Patients with PLMD may have other sleep disorders, such as obstructive sleep apnea, which the use of clonazepam could worsen.

    The drugs used to treat Parkinson’s disease are also very effective against PLMD. These include, L-dopa/carbidopa, bromocriptine (which suppresses the excretion of prolactin), pergolide, and selegiline. If either benzodiazepines or Parkinson’s medications do not relieve symptoms, then narcotics, such as codeine, oxycodone, methadone, and propoxyphene are sometimes employed.

    The causes of PLMD are unknown. The vast majority of PLMD cases occur independently of other disease processes. It is certain that these conditions often cause insomnia, and some research shows that they might also be caused by other sleep disturbances.