Validation of the Johns Hopkins restless legs severity scale.

Determine reliability and validity of the Johns Hopkins restless legs severity scale (JHRLSS), an easily used clinical scale assessing severity of the restless legs syndrome (RLS). There is, prior to this study, no validated scale assessing the wide range of RLS severity. The JHRLSS has been used in prior studies to assess RLS severity, but has not previously been validated in relation to direct measures of the morbidity associated with RLS. A consecutive case series of 31 RLS patients was used in the study. The JHRLSS was validated by its correlation with objective measures by a polysomnogram of the sleep disturbances associated with RLS (periodic leg movements of sleep per hour (PLMS/h), and sleep efficiency). Reliability was determined from the independent ratings of two clinicians. Reliability measures for the JHRLSS based on inter-rater agreement were 0.91 (Spearman Rho) and 0.87 (Cramers V). The subjective JHRLSS correlated significantly with both objective measures of sleep: sleep efficiency (R=0.60, P<0.01) and PLMS/h (R=0.45, P=0.01). The JHRLSS provides a reliable, valid, easily used clinical assessment of RLS severity.