Many seniors think they are sleeping at night only to awaken tired every day for years because their legs jerk and interrupt their sleep. These involuntary leg movements may be due to PLMD. Some seniors are aware of the sleep disorder and may also experience Restless Leg Syndrome in the daytime but assume that treatment is not available. Others may attribute daytime fatigue to getting older, but chronic fatigue and daytime sleepiness is not a normal change of aging.
What is Periodic Leg (or Limb) Movements Disorder?
Half of seniors are affected by PLMD, formerly called nocturnal myoclonus, which is a neurological condition that occurs after a person goes to sleep. Muscles involuntarily jerk rhythmically and repetitively every 15 to 45 seconds on one or both sides of the body. These motions are similar to those in some types of seizure activity. Common joints involved with PLMD include:
- Big toe
The motions might be subtle to quite dramatic. Each moving episode lasts for about two seconds. There may have periods in which the person sleeps for a period of time without the jerking movements but the movements may continue again in clusters, particularly during the first half of the night during the non-REM phase of sleep, according to the Harvard Health Publications article entitled “Movement disorders and parasomnias.” For example, if a person with PLMD experiences jerking sensations every 30 seconds for an eight hour night, he might move nearly 1,000 times that night. These movements can disturb sleep cycles but may not fully awaken the person with PLMD.
According to a 2015 Harvard Health Publications article in Improving Sleep: A Guide to Getting a Good Night’s Rest entitled “Movement Disorders in Sleep” mentions that PLMD affects approximately 50% of seniors. Many cases are undiagnosed and leave the senior suffering from fatigue, daytime sleepiness, and strained relationships with a bed partner who may be kept awake from movements, shaking of the bed, or being kicked or hit repetitively. People who are chronically sleep deprived may begin to fall asleep during the day without realizing it, which can be particularly dangerous if the person is driving at the time.
Causes and Diagnosis of PLMD
Some people with PLMD have no known cause, which is called primary PLMD. Secondary PLMD has a known cause, and symptoms of PLMD may improve if the cause is treated. Diabetes and kidney failure are commonly associated with PLMD. Low iron levels and anemia may cause PLMD, and correcting the deficiency seems to greatly help symptoms. A gluten-free diet may improve symptoms in a person with iron deficiency due to celiac disease. Spinal cord injuries, spinal cord tumors, and sleep apnea may also be associated with Periodic Limb Movement Disorder. Some medications, such as certain antidepressants, may worsen symptoms.
A physician will usually take a detailed history related to fatigue, sleep deprivation, and possible causes. Reports from someone in the household who has witnessed these jerking motions can greatly help, and sometimes a polysomnography (sleep lab study) is ordered in order to observe and document the person’s movements during sleep.
Treatment for PLMD
According to the WebMD article last edited on January 1, 2007 by Leonard J. Sonne, MD entitled “Periodic Limb Movement Disorder,” at least eighty percent of people with Periodic Limb Movement Disorder also have Restless Legs Syndrome (RLS). People with RLS experience uncomfortable feelings in the legs relieved by movement when the person is awake.
Hope for a Better Night’s Sleep
Approximately 50% of seniors experience PLMD. Many experience chronic daytime sleepiness and fatigue and have no idea why. Some may know of the jerking movements but assume that no effective treatment is available. Many seniors with PLMD can be helped by simple strategies used for Restless Leg Syndrome and perhaps medications used to treat RLS. Treatment can greatly improve quality of life for the person experiencing PLMD and for anyone sleeping in the same bed.
This article is for informational purposes and is not intended to be medical advice. Contact your healthcare provider regarding specific concerns related to insomnia, fatigue, and abnormal sleep habits.