Use of actigraphy to objectively measure motor restlessness in Restless Legs Syndrome

Abstract

Restless Legs Syndrome (RLS) is a disorder characterized by disagreeable leg sensations, usually prior to sleep onset, which cause an almost irresistible urge to move the legs. A characteristic feature of this disorder is that the movements are partially or completely relieved with leg motions. Attempts to find the underlying pathology have been unsuccessful. Thus, there are no objective physiological tests to diagnose this condition. Using the Suggested Immobilization Test (SIT), the current study attempted to validate a new and practical method for quantifying the motor symptoms of RLS, actigraphy. To this end, the SIT with actigraphy was evaluated for its usefulness as either a diagnostic or screening tool using indices of sensitivity, specificity, false positive and false negative rates, taking base rates into account. The actigraphic SIT was not found to be an effective diagnostic or screening tool. Further advancements in actigraph technology and future research may eventually provide evidence of an actigraphic SIT being an effective screening or diagnostic tool, despite the findings in the present study. Limitations in actigraph technology were encountered. These limitations are described, as well as the implications for the current study and similar existing research.