Is a diagnosis of ancillary restless legs syndrome reproducible over time? Experience with the Wayne Hening telephone diagnostic interview

Abstract Objective The Hening telephone diagnostic interview (HTDI) is a validated structured diagnostic instrument for restless legs syndrome (RLS). A diagnosis of ancillary RLS is defined as RLS with non bothering or only sporadic occurrence of RLS symptoms. The aim of our study was to test the reproducibility of a previously received diagnosis of ancillary RLS with the HTDI in a telephone follow-up examination. Methods Patients with a diagnosis of ancillary RLS underwent a telephone follow-up after an interval of 6 or more months from their entry into the RLS database. The interview included the HTDI, the International RLS Study Group severity rating scale (IRLS) and questions on current RLS medication. Results Sixty patients with ancillary RLS were eligible for this study, 50 participated. Thirty-six patients were assigned to definite RLS, 11 to probable RLS, one to possible RLS, and two patients were rated as not RLS. Median IRLS score of those with RLS was 10 (0–30). Conclusions This is the first study to report results of the German version of the HTDI. We demonstrate a high reproducibility of a diagnosis of ancillary RLS over time and that the HTDI is an excellent diagnostic tool for RLS even in ancillary cases.