PLMS (Periodic Leg Movement during Sleep) a sleep disorder characterized by involuntary movements of the legs while asleep. People who suffer from PLMS can be unaware of their limb movements, as they do not always wake from them.
These movements happen during the night, at regular intervals before one enters REM sleep. Sufferers often complain of the inability to fall asleep or to remain asleep in association with PLMS. Men and women are equally affected by PLMS; children may develop it as well. This disorder is most common in people over the age of 65, although one may develop it at any age.
If the individual experiences consequences like loss of sleep, irritability or mood changes from Periodic Limb Movements during Sleep, then they have Periodic Limb Movement Disorder PLMD.
People who suffer from PLMS often complain of difficulty falling asleep or staying asleep due to the limb movements they experience. Chronic disruption of sleep can lead to daytime sleepiness, irritability or general changes in mood. The characteristic movements associated with PLMS usually occur in the legs, but less commonly can occur in the arms as well. Those with extreme movements may find themselves waking up at their own movements, and will almost certainly disturb and arouse their partners. Couples are often forced to sleep in separate beds when one or both of them have advanced cases of PLM.
Not everyone with PLM’s is considered to have PLMD though. Those with only mild forms of PLMS that suffer no consequences from the involuntary limb movement, such as waking up themselves or others, are classified as having periodic limb movements of sleep (PLMS), for which it is considered unnecessary to seek treatment for. In rare cases PLMS can also occur while awake, called periodic limb movements of wakefulness (PLMW)
These rhythmic movements usually consist of involuntary extension of the big toe and then progress to an upward bending of the knee, ankle or hip. The symptomatic limb movements will usually persist over a certain interval, lasting from a few minutes up to several hours. Within these events, the leg movements will occur about 5 – 90 seconds apart and last from .5 seconds to 10 seconds.
Sufferers of PLMS may also experience some of the same symptoms of RLS like burning, tingling sensations or general discomfort in their legs when they lay down to rest. Not everyone who has PLMS has RLS; however, about 80% of people who suffer from RLS also suffer from PLMS.
Often ones bed partner will be more aware of the movements than the sufferer is. Many times when one suffers from PLMS, they may not fully awaken from the movements, although it does disrupt their sleep. Additionally, one may find they frequently wake up just as they are falling asleep and not know what work them, as the leg movements usually last only a few seconds.
These movements will often occur in the first stage of your sleep cycle, before REM sleep. REM sleep is the “dream cycle” of sleep; it is also the episode in which one obtains their most restful sleep. Constant disruptions of the sleep cycle can keep one from attaining REM sleep, leaving a person unrested in the morning. During the REM sleep cycle a persons voluntary muscles are paralyzed, which keeps one from acting out their dreams. It is possible that because of this paralysis, PLMS can only occur before or after REM sleep.There is cross over between individuals with PLMS and Restless Legs Syndrome (RLS).
What Is The Cause Of Periodic Leg Movement during Sleep(PLMS)?
While there is no known exact cause of PLMS, researchers are working to find the cause and new treatment options. Currently scientists think that the central nervous system and PLMS could be related, but no studies have proven links between central nervous system abnormalities or disorders and PLMS.
In addition to actual physical movement of the limbs, many people with PLM will experience involuntary tightening or flexing of the muscles, which can be quite painful and disconcerting, and causes the subject to wake up at a high frequency. PLM can occur throughout the night, but in most patients occurs in batches, lasting from 30 minutes to 2 hours on average, with actual movements happening every 5 to 90 seconds during that span. Physical movements are likely to occur in both limbs, while involuntary tightening or flexing of the muscles is more likely to occur in just one limb. PLM typically occurs in the slow-wave phase of sleep just before the deep sleep of REM (rapid eye movement) sleep.
PLM is found with high frequency in those suffering with restless legs syndrome, with as many as 85% of people with RLS also having PLM. Conversely, the number of people with PLM also having RLS is quite low, owing to the fact that PLM is somewhat more common than RLS. Like RLS, PLM can occur in the legs or arms, but most often appears in the legs.
Many underlying medical conditions that cause RLS (restless leg syndrome) may cause PLMS as well. Research shows that anemia, iron deficiency, CNS problems, and kidney disorders may cause RLS and may cause symptoms of PLMS as well. A hereditary link has been seen in people suffering from RLS, the same may be true for people suffering from PLMS. While these conditions can be associated, they are not found to cause one and other, they are only seen as being generally related.
While PLMS by it’s self is not a medically serious condition it can make life unpleasant. Many people who suffer from PLMS often complain of daytime sleepiness, fatigue or feeling unrested when they awake. These symptoms alone can make day-to-day life difficult. If one is unaware of their symptoms, and they are severe enough, PLMS can be a cause of chronic insomnia. PLMS, like RLS, can also be an indicator of more serious underlying medical conditions like diabetes, kidney disease or anemia.
If a person thinks they suffer from PLMS or experiences RLS symptoms like burning or general discomfort in their lower legs, one may want to see a health care professional. A medical provider may want to review your medical history and request a current physical. The medical provider may also ask ones bed partner some questions about their sleep habits; often when people suffer from PLMS the movements will wake their bed partner as well.
PLM is found in 5% of adults over 30, and nearly 50% of adults over the age of 65, lending credence to the claim that it is tied to the immune system, and more likely to appear in those with weaker immune systems. It occurs rarely in children. Detailed studies of it have not been conducted though, so detailed statistics on the variance between genders, and its genetic disposition are unknown with any certainty.
PLM has roots in other sleeping disorders, is more likely to occur in patients with those disorders. This includes the aforementioned RLS, as well REM sleep behavior disorder and narcolepsy. Like RLS, it may also have a connection to low iron levels, specifically low iron levels in the brain.
A link has also been found between people with spinal cord injuries having a higher prevalence of PLM.
Treatment for PLM is similar to the treatment for RLS, so someone with both conditions will likely find relief from both syndromes with one treatment. This includes iron supplements when low iron levels are considered to be at the root of the problem and anti-seizure medications. For extreme cases, sleeping pills or pain killers may be prescribed.
Additionally, changes in your daily routine will probably be recommended. This includes a healthier diet and balanced exercise schedule. Most important is to implement good sleep hygiene practices. This will improve the speed you reach REM sleep, and your ability to stay in it. The chances of PLM occurring during REM sleep are much lower than while in earlier sleep phases. Good sleep hygiene includes improving the sleep conduciveness of the environment you sleep in, having a comfortable bed and pillow that is right for you, and avoiding stimulants of any kind before bed time.
Because of the nature of the disorder, many people may not know they are suffering from it until told by another, as in most cases the PLM will not cause the subject to rouse. Only in the case of extreme jerks or movements, or painful tightening of the muscles is the subject likely to awaken. In all but the most severe cases, treatment will not need to be sought, but as it may be tied to another disorder or medical condition, a doctor should still be consulted concerning it.
The polysomnogram (overnight sleep study) is the best method for detecting the severity of the movements, and also for detecting any other possible sleeping disorders that may be contributing to it.
A medical professional may recommend that a person have a sleep study done to monitor ones movement during sleep. Sleep studies are typically done in a hospital or a sleep center. For the sleep study one will typically spend a night in a private room near the sleep technicians, so they are able to monitor a persons sleep experiences and physical information. A sleep study may also ascertain whether or not a persons’ PLMS is related to other sleep conditions like RLS, sleep apnea or other breathing problems.
PLMS is only diagnosed as a disorder when the symptoms cannot be explained by another condition like RLS. A medical provider may also determine it would be best for one to see a sleep specialist or refer you to a sleep center for further testing and diagnosis.
If your symptoms are very frequent or severe, your medical provider may prescribe medications. The medications most frequently prescribed are dopamine agonists or benzodiazepines. Dopamine agonists are commonly prescribed for Parkinson’s disease to control the associated tremors. Benzodiazepines are a class of anticonvulsants, commonly prescribed for seizure disorders. Both of the types of medications work by suppressing abnormal central nervous system activity. Successful management of PLMS has been found with each of the classes of medication.
Many people who suffer from mild or moderate PLMS Periodic Limb Movements during Sleep (Periodic Leg Movements during Sleep) can successfully manage their condition with out medication. People often report that relaxation exercises like yoga or meditation can help reduce their symptoms. Some times a hot bath or messaging ones legs before going to sleep will help with the movements as well.
© 2021 American Sleep Association.