Sleeping Disorders

Periodic Limb Movement Disorder (PLMD)

Periodic Limb Movement Disorder (PLMD) (also called Nocturnal Myoclonus) is a sleep disorder where the sufferer moves involuntarily during sleep.  This can range from a small amount of movement in the ankles and toes, to slow jerking movements, right up to wild flailing of all arms and legs.  These involuntarily movements are more common in the legs than arms.
PLMD also affects the sufferer’s ability to sleep at night and function normally during the next day.
Periodic Limb Movement Disorder (PLMD) is related to Restless Leg Syndrome (RLS, see section 4.11) in that 80-90% of people with RLS also have PLMD.  However, the reverse is not true, most people with PLMD do not experience or develop RLS.
There are two types of Periodic Limb Movement Disorder (PLMD), and they are categorized on when the involuntarily movements occur:
· during sleep, the condition is called Periodic Limb Movement while Sleeping (PLMS), or,
· while awake or while waking, the condition is called Periodic Limb Movement while Waking (PLMW).

Symptoms

Periodic Limb Movement Disorder (PLMD) is a sleep disorder where the patient moves involuntarily during sleep.  This can range from a small amount of movement in the ankles and toes, right up to wild flailing of all arms and legs.  These involuntarily movements are more common in the legs than arms.
These involuntarily movements occur for between 0.5 and 10 seconds apart and recur at intervals of 5 to 90 seconds for periods lasting from a few minutes right up to an hour or more.

Causes

The exact cause for Periodic Limb Movement Disorder (PLMD) is not known at this time, however, some potential causes and triggers for Periodic Limb Movement Disorder (PLMD) have are suspected and include:
· Age: The incidence of PLMD increases with age.  It is estimated that 5% of people aged 30 to 50 and 44% of people aged over 65 are affected by PLMD.
· Links to Other Sleep Disorders: As many as 12.2% of patients suffering from insomnia and 3.5% of patients suffering from excessive daytime sleepiness may experience PLMD.  Periodic Limb Movement Disorder (PLMD) is related to Restless Leg Syndrome (RLS) in that 80-90% of people with RLS also have PLMD.  However, the reverse is not true, most people with PLMD do not experience RLS.
· Genetics: there are some links to heredity.
· Medical and Other Issues: and medical causes have also been linked to PLMD such as:
o alcoholism,
o caffeine consumption,
o fatigue,
o hot temperatures or extended time in cold temperatures.
o iron deficiency anemia,
o kidney disorders,
o muscle disorders,
o nerve problems,
o poor blood circulation in the legs,
o smoking,
o starting or stopping certain medications, and,
o vitamin or mineral deficiencies.

Diagnosis

People with Periodic Limb Movement Disorder (PLMD) do not usually feel or remember their nighttime movements, but they may complain of restless sleep or Excessive Daytime Sleepiness (ESD).  If you suspect that you suffer from restless sleep or ESD, then you should have a sleep study done at a Sleep Disorders Center.
Because of the similarities between various sleep disorders, polysomnography plays an important role in confirming or otherwise a diagnosis for PLMD or some other sleep disorder.  A Polysomnogram is a device that continuously records the brain waves and a number of other nerve and muscle functions during nighttime sleep, the results of which can be used to detect and distinguish between a range of possible sleep disorders.
A formal diagnosis of PLMD requires three PLMD episodes during the night, each lasting from a few minutes to an hour or more, and each containing at least 30 involuntarily movements followed by partial arousal or awakening.

Complications / Issues

In addition to a disturbed sleep for the Periodic Limb Movement Disorder (PLMD) sufferer and their family / partner, PLMD can also be a cause of insomnia and Excessive Daytime Sleepiness (EDS).

Treatment

At this time, there is no cure for Periodic Limb Movement Disorder (PLMD), and treatment does not and cannot cure PLMD but it can relieve the symptoms.
Some prescription medications are available for treating Periodic Limb Movement Disorder (PLMD).  However, improved sleep hygiene is also an effective treatment, and most PLMD sufferers can reduce their symptoms by following good sleep hygiene practices:
- exercise regularly (but not too close to bedtime),
- ensure that they get enough sleep,
- keep a regular sleep diary, and,
- reducing stress levels in their lives.
Avoiding medical and other issues that are known to trigger, or are suspected to trigger, PLMD is also a key strategy for treating PLMD and reducing or eliminating the symptoms of PLMD.  See section 4.9.2 Causes above.
The following medications are available that either reduces the movements or helps the person sleep through the movements:
- Anticonvulsant agents: These medications reduce muscle contractions in some people, and often help people who experience the painful sensations during episodes.  Gabapentin (Neurontin) is one of the most widely anticonvulsant drugs in the treatment of Periodic Limb Movement Disorder (PLMD) and Restless Leg Syndrome (RLS).
- Benzodiazepines: These drugs suppress muscle contractions and assist in staying asleep and reducing awakenings from the movements.  They are also sedatives and help you sleep through the movements.  Clonazepam (Klonopin) is one of the most widely used benzodiazepines to treat Periodic Limb Movement Disorder (PLMD) and Restless Leg Syndrome (RLS).
- Dopaminergic agents: These drugs are used to increase the levels of an important neurotransmitter (brain chemical) called dopamine, which is important in regulating muscle movements.  These medications are effective in some people, but not in others.  Levodopa / carbidopa combination (Sinemet), ropinirole, pramipexole (Sifrol in the US, Mirapexen in the EU), and pergolide (Permax) are commonly used medications for Periodic Limb Movement Disorder (PLMD) and Restless Leg Syndrome (RLS).
- GABA agonists: These agents inhibit release of certain neurotransmitters that stimulate muscle contractions.  The result is relaxation of contractions.  Baclofen (Lioresal) is one of the most widely agents in the treatment of PLMD.
Please Note: many of the medications used to treat PLMD are the same as those used to treat Restless Leg Syndrome (RLS).  See section 4.11.5 Treatment below.

Prevention

The best way to prevent the onset of the symptoms and complications of Periodic Limb Movement Disorder (PLMD) is for the sufferer to work with their doctor, so that the causes can be treated, removed, or reduced.

Rapid Eye Movement Behavior Disorder (RBD)