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Mood Symptoms and Restless Legs Syndrome Without Periodic Limb Movements During Sleep: Is it a Clinical Subtype?
Hochang B Lee1, Mei Ling Song1, Brian B Koo1
1From the Dept. of Psychiatry, Yale University School of Medicine, New Haven, Conn. (HBL); the Dept. of Nursing Graduate School, Keimyung University, Daegu, South Korea (MLS); the Dept. of Neurology, Yale University School of Medicine, New Haven, Conn. (BBK); and the Dept. of Neurology, Dongsan Medical Center, Keimyung University School of Medicine, Daegu, South Korea (YWC).
Abstract:
Frequently co-occurring restless legs syndrome (RLS) and periodic limb movements during sleep (PLMS) are postulated to share common pathophysiology. The authors compared clinical characteristics and polysomnography (PSG) parameters among 155 idiopathic, untreated RLS patients who were stratified into three groups based on periodic limb movement index (PLMI). The authors found that RLS patients without PLMS (PLMI <5) had higher depression and anxiety scores, a lower total arousal index, longer latency to REM, and a higher spontaneous arousal frequency on PSG than RLS patients with PLMS. RLS severity was associated with PLMI in RLS patients with PLMS but not without PLMS. RLS without PLMS seems to be a phenotypically distinct clinical subtype of RLS. Future study should examine whether RLS without PLMS has a different clinical course, treatment response, and pathophysiology than RLS with PLMS.
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