From the Guidelines
The movement of one leg during sleep at a frequency of 0.3 to 4 Hz is likely periodic limb movement disorder (PLMD), a sleep disorder characterized by repetitive movements of the lower extremities that occur roughly every 15–30 seconds, as detected on polysomnography. According to the American Academy of Sleep Medicine clinical practice guideline 1, PLMD is diagnosed when these movements are frequent (> 15 events/h in adults and > 5 events/h in children), and there is coexisting clinically significant sleep disturbance and/or daytime dysfunction. The guideline provides a comprehensive update of the available evidence and a synthesis of clinical practice recommendations for the treatment of PLMD in adults and children.
Key Characteristics of PLMD
- Brief (0.5–10 seconds), recurrent movements of the lower extremities
- Occur roughly every 15–30 seconds
- Detected on polysomnography
- Often associated with electroencephalogram arousal, elevations in heart rate, and blood pressure
- High night-to-night variability in both adults and children
Treatment and Management
Treatment of PLMD typically involves addressing any underlying conditions, and first-line medications may include dopamine agonists, such as pramipexole or ropinirole, taken 1-2 hours before bedtime, as recommended by the guideline 1. Lifestyle modifications, including regular exercise, avoiding caffeine and alcohol in the evening, and maintaining a consistent sleep schedule, can also help alleviate symptoms.
Impact on Quality of Life
PLMD can significantly disrupt sleep quality, leading to daytime fatigue, even if the person doesn't fully awaken during episodes, as noted in the guideline 1. Therefore, effective treatment and management of PLMD are crucial to improve sleep quality, reduce daytime fatigue, and enhance overall quality of life.
From the Research
Movement of One Leg During Sleep
The movement of one leg during sleep at a frequency of 0.3 to 4 Hz is related to periodic leg movement disorder (PLMD) and restless legs syndrome (RLS).
- The frequency of leg movements during sleep can be detected automatically using computer methods, with high sensitivity and low false-positive rates 2.
- The American Academy of Sleep Medicine has published rules for recording and scoring leg movements during sleep, including periodic leg movements during sleep (PLMS) 3.
- Treatment options for RLS and PLMD include dopaminergic therapies, such as pramipexole and ropinirole, as well as non-dopaminergic therapies, such as gabapentin enacarbil and pregabalin 4, 5, 6.
- The choice of treatment depends on the severity of symptoms, the presence of augmentation, and the patient's medical history 4, 6.
Detection and Scoring of Leg Movements
- Leg movements during sleep can be detected using electromyogram (EMG) signals, which are digitally band-pass filtered and rectified 2.
- The detection of leg movements is performed using two thresholds: one for the starting point and another to detect the end point of each leg movement 2.
- The sensitivity and false-positive rate of automatic detection methods can be evaluated using visual analysis and statistical methods, such as the Kendall W coefficient and the Bland-Altman plots 2.
Treatment Options
- Dopaminergic therapies, such as pramipexole and ropinirole, are effective treatments for RLS and PLMD, but may have limitations, such as augmentation 4, 5, 6.
- Non-dopaminergic therapies, such as gabapentin enacarbil and pregabalin, may be effective alternatives to dopaminergic therapies, with a lower risk of augmentation 4, 6.
- Iron supplementation may be recommended for patients with low ferritin levels 4, 6.