Original article The Johns Hopkins telephone diagnostic interview for the restless legs syndrome: preliminary investigation for validation in a multi-center patient and control population Wayne A. Hening a, * , Richard P. Allen b , Stacey Thanner b , Tinna Washburn b , Debbie Heckler b , Arthur S. Walters a,c , Christopher J. Earley b a Department of Neurology, University of Medicine and Dentistry of New Jersey/RW Johnson Medical School, New Brunswick, NJ, USA b Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD, USA c NJ Neuroscience Institute at JFK Medical Center, Edison, NJ, USA Received 15 August 2002; received in revised form 6 January 2003; accepted 8 January 2003 Abstract Study objectives: To develop and validate a telephone diagnostic interview (the Johns Hopkins telephone diagnostic interview for restless legs, abbreviated TDI) for diagnosis of the restless legs syndrome (RLS). Design and methods: Using the International RLS Study Group diagnostic criteria, specific questions were developed reflecting the diagnostic features of RLS. Seventy-five subjects (37 previously diagnosed RLS patients and 38 controls self-reported to be free of RLS) were interviewed by three expert interviewers blinded to each others’ interviews and the patient’s clinical status. The interviewers diagnosed each subject based on responses to the TDI. Results: The interviewers overall correctly diagnosed 72 of 75 individuals. Minimum interviewer sensitivity and specificity were 97 and 92%, respectively. The intraclass correlation coefficient (ICC) was used to quantify inter-rater reliability for the three interviewers. The ICC for diagnosis was 0.95. The ICC calculated on other key items in the interview exceeded 0.80 in all cases. The patients were predominantly older individuals with long-standing RLS; 19 of them scored at the highest level of severity on the Johns Hopkins Restless Legs Severity Scale (JHRLSS). The interviewers had more difficulty with assessing the controls accurately, some of whom were probably incorrectly self-categorized as not having RLS. Conclusions: The TDI is a sensitive, specific, and reliable instrument for diagnosing RLS by experienced interviewers in a brief, anonymous telephone encounter. q 2003 Elsevier Science B.V. All rights reserved. Keywords: Restless legs; Diagnosis; Validation; Questionnaire; Reliability; Sensitivity; Specificity 1. Introduction The ‘gold standard’ for diagnosing the restless legs syndrome (RLS) remains the expert clinical interview. In order to conduct reliable and valid epidemiological studies, investigators need instruments, which are capable of diagnosing RLS efficiently and accurately without sustained clinical interaction. A telephone diagnostic interview (TDI) developed at the Johns Hopkins Center for RLS is one such instrument. It was based on extensive international clinical experience, which is reflected in the published consensus of the International RLS Study Group (IRLSSG) [1]. The four specific diagnostic features are all based on the patient’s history: 1. the need or urge to move usually based on uncomfortable sensations, primarily if not exclusively in the legs; 2. motor restlessness (actual movement that successfully relieves symptoms); 3. provocation of the first two symptoms by rest (sitting, lying, inactivity) with relief by activity; and 4. circadian variation of symptoms with symptoms usually worst in the evening and at night in the hours before and during the normal time in bed. The primary purpose of this instrument then is to facilitate diagnosis without a face-to-face interview. The current study is an initial validation of the instrument performed on a clinical population of RLS patients and non- patient controls. 1389-9457/03/$ - see front matter q 2003 Elsevier Science B.V. All rights reserved. doi:10.1016/S1389-9457(03)00006-6 Sleep Medicine 4 (2003) 137–141 www.elsevier.com/locate/sleep * Corresponding author. 321 Avenue C (1-F), New York City, NY 10009- 1643. Tel.: þ1-212-477-7527; fax: þ 1-410-550-8078. E-mail address: waheningmd@aol.com (W.A. Hening).