Sleep-Related Movement Disorders

If you’ve ever felt like your body just won’t settle down at night—whether it’s twitching legs, sudden jerks, or strange sensations that make it hard to relax—you may be wondering, “What’s going on?” These kinds of nighttime movements can be exhausting, especially when they keep you from getting the rest you need. Sleep-related movement disorders (SRMDs) are a group of conditions that cause repetitive or unusual movements during sleep or while trying to fall asleep. There are more than half a dozen SRMDs, including some movements that are considered normal variants or nonpathologic and include: 

If you’ve ever felt like your body just won’t settle down at night—whether it’s twitching legs, sudden jerks, or strange sensations that make it hard to relax—you may be wondering, “What’s going on?” These kinds of nighttime movements can be exhausting, especially when they keep you from getting the rest you need. Sleep-related movement disorders (SRMDs) are a group of conditions that cause repetitive or unusual movements during sleep or while trying to fall asleep. There are more than half a dozen SRMDs, including some movements that are considered normal variants or nonpathologic and include: 

Sleep-Related Movement Disorders

Sleep-Related Movement Normal Variants  

  • Excessive fragmentary myoclonus 
  • Hypnagogic foot tremor or alternating myoclonus
  • Sleep starts or hypnic jerks

As our education and resources expand, all of the SRMD will be included in this section. For now, we’ll start by reviewing RLS and PLMD

Restless Legs Syndrome

RLS is a condition that can make it really hard to relax, especially in the evening. RLS is a clinical diagnosis, meaning that the reporting of symptoms consistent with the diagnosis is sufficient to make the diagnosis. However, testing may be performed to exclude RLS mimics or to evaluate for factors that contribute to increased risk for RLS. People with RLS often feel strange, hard-to-describe sensations deep in their legs—some say it feels like something is crawling, tugging, or even burning. These feelings create a strong urge to move the legs, which usually brings some relief, at least for a little while. The symptoms tend to show up during quiet moments, like when you’re trying to fall asleep or just sitting still, making it tough to unwind and get the rest you need. In children and individuals with neurodivergence or those with more limited ability to express what they feel, it may be difficult to identify a history. In these situations, the diagnosis may be based on bedtime observations of pacing, restlessness, or desire to have arms and/or legs massaged. 

RLS tends to affect women more often than men, it’s especially common during pregnancy, and it is also seen more frequently in people with certain health conditions, like end-stage renal disease.1 It is notable that the development of either RLS or PLMD can be suggestive of interval worsening of an underlying illness. 

If you’re living with RLS, falling asleep can be one of the hardest parts of the day. Challenges falling asleep are tied to the fact that symptoms tend to start with quiet and relaxation, leading to shorter and more disrupted sleep and a negative impact on your daytime performance and quality of life.2 Most people with RLS have periodic limb movements of sleep (PLMS)–repetitive, involuntary leg movements that happen during sleep. However, not everyone with PLMS has RLS. Because there’s no specific test to confirm RLS, doctors rely on a person’s description of their symptoms and medical history to make a diagnosis. That’s why it’s so important to speak up about what you’re feeling—your story is the most valuable tool in finding answers and getting support.

RLS Diagnostic Criteria3

Criteria A-C must be met

  1. A complaint of an urge to move the legs, usually accompanied by or thought to be caused by uncomfortable and unpleasant sensations in the legs. These symptoms must:

1. Begin or worsen during periods of rest or inactivity such as lying down or sitting.

2. Be partially or totally relieved by movement, such as walking or stretching, at least as long as the activity continues.

3. Occur exclusively or predominantly in the evening or night rather than during the day.

  1. The above features are not solely accounted for by a condition that mimics RLS (eg, leg cramps, positional discomfort, myalgia [muscle pain], venous stasis [pooling of blood within the veins], leg edema [swelling], arthritis, habitual foot tapping).
  2. The symptoms of RLS cause concern, distress, sleep disturbance, or impairment in mental, physical, social, occupational, educational, behavioral, or other important areas of functioning.

The Treatment of RLS

The approach to treating RLS should always start with a careful consideration of any provoking factors such as other medical disorders, nutritional deficiencies, or medications that may be contributing to symptoms. Your doctor will likely check your iron levels, as low iron can play a role in RLS symptoms. If your iron levels are low, iron supplements may help bring some relief, along with behavior or lifestyle changes.2 

In January 2025, the American Academy of Sleep Medicine (AASM) published updated guidelines for the treatment of RLS and PLMD.2 The guidelines provide the following “Good Practice Statement,” essentially these are good things for all individuals with RLS. 

  1. Iron studies, which should include serum iron studies, ferritin level, and transferrin saturation (a calculation based on iron and total iron binding capacity) should be evaluated regularly.
    1. Consider the following when having these tests done:
      1. Have blood drawn in the morning, if possible 
      2. Avoid taking iron supplements the day before and leading up to the test
      3. Consider fasting 
    2. The results of these tests will help determine if iron supplementation is recommended and how it should be given, based on expert consensus.
      1. In adults, supplementation of iron with oral or intravenously administered iron is indicated if the serum ferritin level is ≤ 75 ng/mL or the transferrin saturation is < 20%, and supplementation only with intravenously administered iron if the serum ferritin level is between 75 and 100 ng/mL.
      2. In children, supplementation of iron should be instituted when the serum ferritin level is < 50 ng/mL with oral or intravenously administered formulations. 
  2. Address any exacerbating factors such as alcohol, caffeine, medications (i.e.,  antihistaminergic, serotonergic, antidopaminergic medications) and untreated obstructive sleep apnea.

According to the update, first-line medication suggested is an alpha-2-delta ligand (eg, gabapentin), which replaced the previously accepted first-line therapy, dopamine receptor agonists. Although these medications were the first US Food and Drug (FDA)-approved therapy for RLS, it has now been discovered that many people treated with these drugs experience a phenomenon called augmentation, which is a paradoxical worsening after an initial improvement of symptoms that may even shift in timing to an earlier onset of symptoms in the day. This phenomenon can have a vicious cycle of a temporary improvement with escalating doses of the dopamine receptor agonist, to only later have worsening again. Finally, people who have severe or disabling symptoms that do not respond to other treatments may find relief with opioids.2,4 The FDA has also approved several nonpharmacologic treatment options for RLS. One is a vibrating pad that is placed under the affected area (typically the legs),5 another is a relaxer foot wrap,6 and the third is a device that delivers high-frequency stimulation to the peroneal nerve.7

Periodic Limb Movement Disorder 

PLMS are small, repetitive leg twitches or jerks that happen while you’re asleep. This is a diagnosis that is made based on the findings of a sleep study, and you may or may not have symptoms of leg discomfort associated. However, in order for it to be considered a disorder, there must be either associated sleep quality impairment or daytime symptoms. And, although RLS and PLMD are distinct disorders, there is overlap with about 80% of people with RLS experiencing PLMD on polysomnography. 

In PLMD, the movements usually follow a regular pattern and can occur every few seconds without the person even realizing it. Many people may have occasional leg movements during sleep. PLMD is diagnosed when these movements happen frequently–more than 15 times an hour during sleep for adults and more than 5 times an hour in pediatrics, as recorded via polysomnography–and interfere with sleep quality or cause daytime symptoms. If you have PLMD, you may not feel rested during the day, even after a full night’s sleep. PLMD is more common in older adults; in people with certain conditions like narcolepsy, diabetes, or rapid eye movement sleep behavior disorder; and in men. Smoking, the use of antidepressant medications, and physical inactivity are also associated with a higher risk of PLMD.8

It can sometimes feel challenging to differentiate RLS from nocturnal leg cramps or other conditions like neuropathy, or nerve damage symptoms, for some people, and in fact, these conditions can sometimes overlap. However, the recognition of the presence of distinct but overlapping conditions is important for treatment considerations. 

PLMD Diagnostic Criteria3

Criteria A-D must be met

  1. Polysomnography demonstrates PLMS.
  2. The frequency of PLMS is > 5/h in children and > 15/h in adults.
  3. The PLMS cause clinically significant sleep disturbance or impairment in mental, physical, social, occupational, educational, behavioral, or other important areas of functioning.
  4. The PLMS and the symptoms are not better explained by another current sleep disorder, medical disorder, or mental disorder (eg, PLMS occurring with apneas, hypopneas, and respiratory effort-related arousals.

The Treatment of PLMD

The updated 2025 guidelines include recommendations against the use of triazolam and valproic acid for the treatment of PLMD.2 Although the guidelines provide no specific recommendation for the treatments of PLMD, it is not uncommon that, in clinical practice, the same attention to factors considered in RLS is also evaluated, with similar medications being used if necessary. The lack of specific recommendations is a result of inadequate research, meaning there are not enough high-quality studies to clearly show what treatments work best. If you’re experiencing symptoms, it’s still important to talk to a healthcare provider—they can help explore options that may improve your sleep and overall well-being.

References

  1. Allen RP, Picchietti DL, Garcia-Borreguero D, et al. Restless legs syndrome/Willis-Ekbom disease diagnostic criteria: updated International Restless Legs Syndrome Study Group (IRLSSG) consensus criteria–history, rationale, description, and significance. Sleep Med. 2014;15(8):860-873.
  2. Winkelman JW, Berkowski JA, DelRosso LM, et al. Treatment of restless legs syndrome and periodic limb movement disorder: an American Academy of Sleep Medicine clinical practice guideline. J Clin Sleep Med. 2025;21(1):137-152.
  3. American Academy of Sleep Medicine. International Classification of Sleep Disorders, 3rd ed, Text Revision. American Academy of Sleep Medicine; 2023.
  4. Silber MH, Buchfuhrer MJ, Earley CJ, et al. The management of restless legs syndrome: an updated algorithm. Mayo Clin Proc. 2021;96(7):1921-1937.
  5. US Food and Drug Administration. De novo classification request for Symphony device. https://www.accessdata.fda.gov/cdrh_docs/reviews/DEN110011.pdf. Published 2011. Accessed May 14, 2025.
  6. US Food and Drug Administration. De novo classification request for Restiffic restless leg relaxer foot wrap. https://www.accessdata.fda.gov/cdrh_docs/reviews/DEN110009.pdf. Published 2011. Accessed May 14, 2025.
  7. Charlesworth JD, Adlou B, Singh H, Buchfuhrer MJ. Bilateral high-frequency noninvasive peroneal nerve stimulation evokes tonic leg muscle activation for sleep-compatible reduction of restless legs syndrome symptoms. J Clin Sleep Med. 2023;19(7):1199-1209.
  8. Joseph V, Nagalli S. Periodic limb movement disorder. 2023 Feb 14. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan–. PMID: 32809562.