Periodic Limb Movement Disorder

Updated: Aug 03, 2021
  • Author: Deepak K Gupta, MD; Chief Editor: Selim R Benbadis, MD  more...
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Periodic limb movement disorder (PLMD) is unique in that the movements occur during sleep. Most other movement disorders manifest during wakefulness. The condition is remarkably periodic, and the movements may cause poor sleep and subsequent daytime somnolence. PLMD may occur with other sleep disorders and is related to, but not synonymous with, restless legs syndrome (RLS), which is a movement disorder with sensory features that manifest during wakefulness. The majority of patients with RLS have PLMD, but the reverse is not true. Treatment involves either dopaminergic medication in an attempt to modify activity of the subcortical motor system or, more commonly, sedative medications to allow uninterrupted sleep. Many new agents are proving efficacious for treatment as well.



The etiology of the primary form of periodic limb movement disorder (PLMD) is uncertain. Suprasegmental disinhibition of the descending inhibitory pathways may be a factor. Vetrugno et al report that evidence supports neuronal hyperexcitability with involvement of the central pattern generator for gait as the pathophysiology of periodic limb movement. [1] This results in decreased dopamine transmission, potentially supporting the use of dopaminergic therapy to treat the condition.

Because the etiology is not clear, treatment is primarily to treat symptoms and does not modify the disease. Studies differ regarding the frequency of polyneuropathy in cases of PLMD. Martinez-Mena and Pastor found that only 1 of 9 patients had signs of neuropathy. [2]

The secondary forms of PLMD may be due to diabetes mellitus, spinal cord tumor, sleep apnea syndrome, narcolepsy, uremia, or anemia. [3] Many authors report an association between attention deficit hyperactivity disorder (ADHD) and PLMD. Family history of restless leg syndrome (RLS) may be a risk factor for PLMD, with a possible underlying genetic component mediated via single nucleotide polymorphisms in BTBD9, TOX3/BC034767 and MEIS1. [4]  Iron deficiency anemia has a well-known association with RLS, but more recently has also been found to be associated with periodic limb movement, with some studies suggesting a possible benefit to iron supplementation in patients with documented deficiency. [5]

Antidopaminergic, dopaminergic, or tricyclic drug therapy or cessation of treatment with barbiturates or benzodiazepines may initiate the syndrome as well. [6] Voderholzer et al noted an increased incidence of periodic limb movements during sleep in patients with Gilles de la Tourette syndrome. [7] However, the authors emphasized that the different responses to pharmacological treatments are evidence against a pathophysiological relationship between PLMD and Gilles de la Tourette syndrome.

Potential risk factors or etiologic factors for secondary PLMD include the following:



The prevalence of periodic leg movements in sleep (PLMS) is estimated to be 4–11% in adults. [8] PLMS are most frequently a symptom of restless legs syndrome (RLS). They also often occur in narcolepsy, sleep apnea syndrome, and rapid eye movement (REM) sleep behavior disorder (RBD). Some patients with otherwise unexplained insomnia or excessive daytime sleepiness exhibit an elevated number of PLMS, a condition defined as periodic limb movement disorder (PLMD).



The idiopathic form of periodic limb movement disorder (PLMD) may be chronic. Relapses and remissions may occur, but treatment does not appear to modify the disease.

The secondary form of this syndrome may cease with treatment of the underlying cause.



Picchietti et al suggested that the sleep disruption in periodic limb movement disorder (PLMD) could contribute to the inattention and hyperactivity of some children who have ADHD. [9]

Some research suggests that periodic limb movements with arousals are associated with subsequent nonsustained ventricular tachycardia (NSVT). A study of older men in their 70s and 80s found that periodic limb movements during sleep with arousal was associated with a threefold increased risk for NSVT shortly after the episode. [10]


Patient Education

Informing the bed partner of the condition is important so that potentially negative physical contact may be explained on a neurological (rather than an intentional) basis.

For excellent patient education resources, visit eMedicineHealth's Sleep Disorders Center. Also, see eMedicineHealth's patient education articles Periodic Limb Movement Disorder, Restless Legs Syndrome, Sleep Disorders in Women, and Sleep Disorders and Aging.