Periodic limb movement disorder (PLMD) is a neurological sleep disorder characterized by repetitive uncontrollable twitching, kicking, and jerking of the legs and, sometimes, the arms during sleep. These involuntary movements occur at regular and frequent intervals, usually every 20 to 40 seconds, but of course, they vary from person to person.

According to current estimation, 4 to 11% of the adult population and 5 to 8% of the child population suffer from periodic limb movement disorder. In fact, the prevalence of PLMD increases with age and up to 34% of 60+ aged people have the disorder.

In addition, although mild PLMD cases may not come with negative effects, those who wake up and have moderate to severe PLMD can suffer from excessive daytime sleepiness, cognitive impairments, and even lack of sleep. Therefore, if daytime fatigue becomes normal or your bed partner regularly complains about your movements, you’d better see a sleep specialist.

Causes of PLMD

The causes of periodic limb movement disorder are numerous and are usually related to many factors. In general, PLMD is a result of an underlying health condition including kidney disease, iron deficiency, spinal cord lesions, and peripheral neuropathy. Furthermore, some medications such as SSRIs or antidepressants and dopamine blockers, as well as other sleep disorders such as restless leg syndrome and sleep apnea can lead to PLMD.

Other risk factors for PLMD include:

• Sedentary lifestyle
• Gene expression
• Magnesium deficiency
• Caffeine consumption
• Smoking
• Diabetes
• Obesity
• Age

Impacts of PLMD

Generally speaking, the main symptom related to PLMD is twitching and jerking of the legs, which occur at frequent and regular intervals, during sleep.

For those who experience movements in 20 to 40-second intervals, PLMD can remarkably affect their sleep quality, in a negative way of course, and disrupt sleep architecture. Frequent movements can lead to frequent awakenings, resulting in a lack of restorative deep sleep. As a result, they will experience extreme daytime sleepiness and fatigue, and impaired cognitive function.

Consequently, if left untreated, the disorder can even take a toll on their physical and mental health. These repeated muscle contractions can result in physical discomfort and muscle soreness, which affects overall physical health, while disrupted sleep architecture and lack of sleep can lead to mood disorders such as anxiety and depression.

Diagnosis of PLMD

As with any other sleep disorder, the first step towards getting a diagnosis is doing a physical exam, sleep history assessment, and overall medical history. Next, a sleep study, i.e. a polysomnogram, is needed as it can detect any movements during sleep.

The sleep study will also help identify or rule out other sleep disorders that may cause movements, such as sleep apnea. And, according to the latest criteria, adults have to experience 15+ while children 5+ movements per hour to be diagnosed with periodic limb movement disorder.

Treatments for PLMD

When it comes to treating PLMD, you must understand that there is no cure for the disorder, but only pharmacological interventions and lifestyle changes that may help alleviate and control symptoms.

Speaking of pharmacological interventions, medications like anticonvulsants, benzodiazepines, and dopaminergic agents are typically prescribed depending on the patient’s needs and medical history. Last but not least, regular exercise, stress reduction, and improving sleep hygiene are the lifestyle changes doctors typically recommend for alleviating limb movements and improving sleep quality.