What is periodic limb movement disorder (PLMD)?
Periodic limb movement disorder (PLMD) is a condition in which a
person's legs, and sometimes arms, move repetitively and uncontrollably while
he or she is asleep. These episodes of limb movement can disrupt the person's
sleep, causing insomnia or daytime sleepiness. Periodic limb movement symptoms
are only considered a disorder (PLMD) when insomnia or daytime sleepiness
cannot be explained by any other problem, such as
restless legs syndrome. Recently, it has been found
that these movements are often linked to subtle breathing problems.
What causes PLMD?
The exact cause of PLMD is unknown.
PLMD shares many underlying factors with restless legs syndrome,
such as a hereditary link, iron deficiency anemia, nerve problems, poor blood
circulation in the legs, kidney disorders, and others. However, the two
conditions are generally seen as being related rather than as causing one
another.
What are the symptoms of PLMD?
People with PLMD have trouble falling or staying asleep (insomnia)
or feel sleepy during the day because the movements disrupt their sleep. These
movements usually are in the legs and occur in some type of pattern. Although a
person often is not fully awakened by these movements, they interfere with
normal sleep cycles. A bed partner's sleep may also be disrupted.
How is PLMD diagnosed?
PLMD is diagnosed with a medical history, often including a sleep
history from a bed partner, and a physical examination. A sleep study is
usually required to detect the movements. A sleep study also can identify other
conditions that may be causing symptoms, such as
sleep apnea or other subtle breathing problems that
may be causing movements.
Many questions remain about the nature of periodic leg movements
and PLMD. Some researchers consider the movements to be normal. At least a few
movements may occur during sleep in people who do not have restless legs
syndrome, especially in the elderly.
How is PLMD treated?
Managing symptoms of PLMD generally includes:
- Home treatment, such as relaxation exercises
or massage.
- Medications, including dopamine agonists such as
ropinirole or pramipexole, benzodiazepines, or the dopamine precursor called
levodopa. These medications, some of which are also used to treat Parkinson's
disease, are used only when symptoms are frequent and severe or regularly
disrupt sleep.