BACKGROUND: Epidemiological survey studies have suggested that a large fraction of the adult population, from five to more than 10%, have symptoms of Restless Legs Syndrome (RLS). Recently, however, it has become clear that the positive predictive value of many questionnaire screens for RLS may be fairly low and that many individuals who are identified by these screens have other conditions that can "mimic" the features of RLS by satisfying the four diagnostic criteria. We noted the presence of such confounders in a case-control family study and sought to develop methods to differentiate them from true RLS. METHODS: Family members from the case-control study were interviewed blindly by an RLS expert using the validated Hopkins telephone diagnostic interview (HTDI). Besides questions on the four key diagnostic features of RLS, the HTDI contains open-ended questions on symptom quality and relief strategies and other questions to probe the character of provocative situations and modes of relief. Based on the entire HDTI, a diagnosis of definite, probable or possible RLS or Not-RLS was made. RESULTS: Out of 1255 family members contacted, we diagnosed 1232: 402 (32.0%) had definite or probable RLS, 42 (3.3%) possible RLS, and 788 (62.8%) Not-RLS. Of the 788 family members who were determined not to have RLS, 126 could satisfy all four diagnostic criteria (16%). This finding indicates that the specificity of the four criteria was only 84%. Those with mimic conditions were found to have atypical presentations whose features could be used to assist in final diagnosis. CONCLUSION: A variety of conditions, including cramps, positional discomfort, and local leg pathology can satisfy all four diagnostic criteria for RLS and thereby "mimic" RLS by satisfying the four diagnostic criteria. Definitive diagnosis of RLS, therefore, requires exclusion of these other conditions, which may be more common in the population than true RLS. Short of an extended clinical interview and workup, certain features of presentation help differentiate mimics from true RLS.
BACKGROUND: Epidemiological survey studies have suggested that a large fraction of the adult population, from five to more than 10%, have symptoms of Restless Legs Syndrome (RLS). Recently, however, it has become clear that the positive predictive value of many questionnaire screens for RLS may be fairly low and that many individuals who are identified by these screens have other conditions that can "mimic" the features of RLS by satisfying the four diagnostic criteria. We noted the presence of such confounders in a case-control family study and sought to develop methods to differentiate them from true RLS. METHODS: Family members from the case-control study were interviewed blindly by an RLS expert using the validated Hopkins telephone diagnostic interview (HTDI). Besides questions on the four key diagnostic features of RLS, the HTDI contains open-ended questions on symptom quality and relief strategies and other questions to probe the character of provocative situations and modes of relief. Based on the entire HDTI, a diagnosis of definite, probable or possible RLS or Not-RLS was made. RESULTS: Out of 1255 family members contacted, we diagnosed 1232: 402 (32.0%) had definite or probable RLS, 42 (3.3%) possible RLS, and 788 (62.8%) Not-RLS. Of the 788 family members who were determined not to have RLS, 126 could satisfy all four diagnostic criteria (16%). This finding indicates that the specificity of the four criteria was only 84%. Those with mimic conditions were found to have atypical presentations whose features could be used to assist in final diagnosis. CONCLUSION: A variety of conditions, including cramps, positional discomfort, and local leg pathology can satisfy all four diagnostic criteria for RLS and thereby "mimic" RLS by satisfying the four diagnostic criteria. Definitive diagnosis of RLS, therefore, requires exclusion of these other conditions, which may be more common in the population than true RLS. Short of an extended clinical interview and workup, certain features of presentation help differentiate mimics from true RLS.
Authors: Wayne Hening; Arthur S Walters; Richard P Allen; Jacques Montplaisir; Andrew Myers; Luigi Ferini-Strambi Journal: Sleep Med Date: 2004-05 Impact factor: 3.492
Authors: Wayne A Hening; Richard P Allen; Mystinna Washburn; Suzanne Lesage; Christopher J Earley Journal: Sleep Med Date: 2007-07-17 Impact factor: 3.492
Authors: Richard P Allen; Daniel Picchietti; Wayne A Hening; Claudia Trenkwalder; Arthur S Walters; Jacques Montplaisi Journal: Sleep Med Date: 2003-03 Impact factor: 3.492
Authors: Wayne A Hening; Richard P Allen; Stacey Thanner; Tinna Washburn; Debbie Heckler; Arthur S Walters; Christopher J Earley Journal: Sleep Med Date: 2003-03 Impact factor: 3.492
Authors: Klaus Berger; Arnold von Eckardstein; Claudia Trenkwalder; Andreas Rothdach; Ralf Junker; Stephan Karl Weiland Journal: J Neurol Date: 2002-09 Impact factor: 4.849
Authors: Michael R Littner; Clete Kushida; W McDowell Anderson; Dennis Bailey; Richard B Berry; Max Hirshkowitz; Sheldon Kapen; Milton Kramer; Teofilo Lee-Chiong; Kasey K Li; Daniel L Loube; Timothy Morgenthaler; Merrill Wise Journal: Sleep Date: 2004-05-01 Impact factor: 5.849
Authors: Kittisak Sawanyawisuth; Lawrence A Palinkas; Sonia Ancoli-Israel; Joel E Dimsdale; José S Loredo Journal: J Clin Sleep Med Date: 2013-01-15 Impact factor: 4.062
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