Can obstructive sleep apnea (OSA) cause periodic limb movement disorder (PLMD)?

From the Guidelines

Sleep apnea can indeed contribute to periodic limb movement disorder (PLMD), as untreated obstructive sleep apnea is one of the sleep disorders associated with high rates of periodic limb movements during sleep (PLMS) 1. When considering the relationship between sleep apnea and PLMD, it's essential to understand that they are distinct sleep disorders that often coexist. The connection between these conditions appears to be related to the disruptions in sleep patterns caused by sleep apnea, which can trigger or worsen PLMD symptoms.

• Key factors to consider include:
  • The frequency and severity of PLMS, which can be detected on polysomnography as brief, recurrent movements of the lower extremities that occur roughly every 15–30 seconds 1.
  • The presence of coexisting clinically significant sleep disturbance and/or daytime dysfunction that is not better explained by another concurrent sleep, medical, neurological, or mental disorder 1.
  • The absence of sleep disorders that are associated with high rates of PLMS, including RLS, untreated obstructive sleep apnea, rapid eye movement sleep behavior disorder, and narcolepsy 1. As noted in the American Academy of Sleep Medicine clinical practice guideline, treatment of the underlying sleep apnea with continuous positive airway pressure (CPAP) therapy often improves both conditions simultaneously 1. Many patients find that when their sleep apnea is effectively managed, their periodic limb movements decrease significantly. This connection likely involves shared neurological pathways related to sleep regulation and arousal mechanisms.
• Important considerations for diagnosis and treatment planning include:
  • A comprehensive sleep evaluation to properly diagnose and treat both conditions 1.
  • The potential for bidirectional relationships between sleep apnea and PLMD, with sleep apnea potentially triggering or worsening PLMD symptoms 1.

From the Research

Relationship Between Sleep Apnea and Periodic Limb Movement Disorder

• Sleep apnea and periodic limb movement disorder (PLMD) are two common sleep disorders that can co-occur in some patients 2, 3, 4, 5.
• Studies have investigated the relationship between sleep apnea and PLMD, with some suggesting that sleep apnea can "unmask" underlying PLMD 3, 5.
• The periodicity of periodic limb movements (PLMs) and obstructive sleep apneas (OSAs) has been found to be different, suggesting that they are not generated by a common central generator 2.

Effect of Continuous Positive Airway Pressure (CPAP) on PLMD

• CPAP treatment for obstructive sleep apnea (OSA) can lead to an increase in PLMs in some patients, particularly those with severe OSA 3, 5.
• In contrast, CPAP treatment can also lead to a decrease in PLMs in patients with mild OSA, possibly due to the resolution of PLMs associated with respiratory effort-related arousals 5.
• The effect of CPAP on PLMD may depend on the severity of OSA, with "unmasking" of underlying PLMD occurring in moderate to severe OSA, and resolution of PLMs occurring in mild OSA 5.

Clinical Characteristics of PLMD in Patients with OSA

• Patients with OSA and PLMD can be categorized into different groups based on their response to CPAP treatment, including those with persistent PLMS, CPAP-emergent PLMS, and CPAP-resolved PLMS 4.
• Clinical characteristics such as age, sex, body mass index, and restless legs syndrome (RLS) can influence the presence and severity of PLMD in patients with OSA 4.
• The prevalence of PLMS in adults is estimated to be 4-11%, and can occur in various medical and neurological disorders, including RLS, narcolepsy, and sleep apnea syndrome 6.