If you can barely wake up in the morning and your bed looks like a battle zone, you may want to ask your doctor about periodic limb movement disorder (PLMD).
It’s bad enough when a sleep condition causes fatigue and disrupted sleep; it’s even worse when that disease starts destroying household linens. Such was the case with a 65-year-old Swiss woman who frequently, and unknowingly, moved her legs while sleeping. In fact, she was so active at night that she rubbed threadbare spots in her bedsheets, where she normally positioned her feet, and had to replace these linens every three months.
Periodic Limb Movement Disorder: A Rough Night
Many people may have rumpled, worn-out bed sheets due to a condition called periodic limb movement disorder (PLMD), sometimes called periodic limb movements in sleep.
During sleep, people with PLMD move their lower limbs, often their toes and ankles and sometimes knees and hips. Periodic leg movements become more common with age — nearly one-third of adults over the age of 60 experience this condition.
Having periodic leg movements “only becomes a disorder if there are symptoms associated with it,” says Ritu Grewal, MD, a sleep physician and pulmonologist with the Jefferson Sleep Disorders Center in Philadelphia. “It only becomes a problem if it disrupts sleep.”
Periodic Limb Movement Disorder vs. Restless Legs Syndrome
Though periodic leg movement disorder shares some similarities with restless legs syndrome, there are also major differences.
Between 80 and 90 percent of patients with restless legs syndrome also have periodic leg movement disorder, Dr. Grewal says. The major difference is that restless legs syndrome occurs while patients are awake and aware of the leg movements; PLMD occurs while the patient is asleep and unaware of what’s going on.
Patients don’t realize what they’re doing at night — it’s their bed partners who usually complain about the leg movements, Grewal says. A clinician must monitor you while you’re asleep in order to diagnose PLMD, which isn’t the case for restless legs syndrome.
Periodic Limb Movement Disorder: Risk Factors
Aside from having restless legs syndrome, other factors that put you at greater risk for periodic leg movement disorder include:
- Narcolepsy, a condition in which people suddenly fall asleep during the day, typically for a few seconds or minutes
- Iron deficiency or conditions associated with low iron, such as pregnancy and kidney disease
- Nerve damage, such as from diabetes
- Certain medication, like antihistamines and antidepressants
Recent research suggests that left-handedness may also be a factor in the severity of PLMD. One study from the University of Toledo Medical Center in Ohio found that 94 percent of left-handed people with PLMD experienced movements on both sides of their body while sleeping, compared with just 69 percent of right-handed patients. The rest had unilateral, or one-sided, movements.
Periodic Limb Movement Disorder: Treatment
Doctors can treat PLMD with a variety of medication, including ropinirole (Requip) and pramipexole (Mirapex), which are also used for restless legs syndrome. Your doctor may also suggest iron supplements if necessary, as well as supplemental magnesium and folic acid.
Regular exercise may be helpful in treating PLMD and reducing symptoms. In addition, resting in an environment that’s conducive to good sleep may be beneficial, according to the American Sleep Association. Having a quiet room and a comfortable bed and pillow can help you quickly reach a stage of sleep in which leg movements are less likely to occur.
You may also ease your symptoms by avoiding caffeinated and alcoholic beverages, tobacco, and antihistamines, particularly late in the day.
If you suspect that you have PLMD, visit a doctor specializing in sleep disorders. Warning signs include sleeping the right amount of hours at night and still feeling tired the next day, and having a bed partner who complains that you continuously kick or twitch your legs, Grewal says. Of course, threadbare spots at the bottom of your sheets can also be a sign of PLMD.
By Eric Metcalf – Medically reviewed by Pat F. Bass III, MD, MPH