Limb sensations in restless legs syndrome (RLS) include an urge to move, a discomfort, or even a frank pain. However, no large studies compared painful to nonpainful RLS as specific phenotypes. We investigated the painful form of RLS in a clinical series of primary RLS patients and a large sample of members of the French RLS association (AFE).
Fifty-six patients with primary RLS (face-to-face interviewed) and 734 AFE members (received by ground mail an self-report questionnaire) responded to the presence/absence of painful RLS sensations and were included. They completed a French reconstruction of the McGill Pain Questionnaire (Questionnaire Douleur de Saint-Antoine [QDSA]) to assess their RLS sensations as well as questions about demographics and clinical RLS features.
Sixty-one percent of interviewed patients and 55% of AFE members had painful RLS sensations. The patients with painful RLS were more sleepy and tired than those with nonpainful sensations. The RLS severity and need for current, dopaminergic treatment were higher in AFE members with painful than with nonpainful RLS. In both the groups, the QDSA qualifier “burning” was the most frequent (37% to 44%) sensory discriminator of painful RLS. In the AFE sample, QDSA scores, and the distribution of words in all QDSA subclasses was skewed toward a more severe connotation with more than one third of patients selecting affective discriminating words like “exasperating,” “exhausting,” and “unbearable.”
Painful RLS appears to be a severe, “burning” subtype of RLS, and could be a distinct disease or a clinical variant in a sensations continuum.
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*Sleep Disorder Unit
§Department of Biostatistics, Pitié-Salpêtrière University Hospital
†Pierre and Marie Curie University
‡Brain and Spinal Cord Research Institute (CRICM)-UPMC/Inserm U1127/CNRS UMR7225, Paris, France
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Supported by a grant from the French RLS association (Association France Ekbom, AFE, Strasbourg, France) to E.G.K. S.L.-S. was a paid speaker for UCB Pharma. I.A. was a paid speaker and consultant for UCB Pharma and Jazz Pharmaceuticals, and investigator plus coordinator for Bioprojet. The remaining authors declare no conflict of interest.
Reprints: Isabelle Arnulf, MD, PhD, Service des Pathologies du Sommeil, Groupe Hospitalier Pitié-Salpêtrière, 47-83 Boulevard de l’Hôpital, 75651 Paris Cedex 13, France (e-mail: firstname.lastname@example.org).
Received February 9, 2014
Received in revised form July 14, 2014
Accepted June 16, 2014