The kickstrip™: A novel testing device for periodic limb movement disorder

Study Objectives: In light of the ongoing debate over the clinical significance of periodic limb movement disorder (PLMD) and its monitoring in overnight sleep studies, we introduce a novel, portable, low-cost device for PLMD testing. The KickStrip is a disposable device, which includes a movement sensor, a central processing unit with real-time software, and a display. In the present study, the KickStrip final score (Kscore) is validated against the traditional periodic limb movement index (PLMI) based on overnight recordings in the sleep laboratory. Design: Patients underwent full polysomnographic recordings concomitantly with the use of the KickStrip for a single night. Setting: Sleep Disorders Unit at Loewenstein Rehabilitation Hospital and Sleep Medicine Center at Rambam Medical Center, Israel, Patients: Eighty-two patients referred for overnight sleep recordings due to sleep disturbance of any kind. Interventions: N/A Measurements and Results: The Kscores were collected and the PLMI computed for each leg separately. Pearson correlations between Kscores and PLMI ranged between r=0.83 to r=0.88 (p<0.001). Sensitivity and specificity values of the Kscores for increasing PLMD thresholds showed sensitivity ranging from 50% to 100% and specificity ranging from 83% to 100%. Receiver operating characteristic curves showed area-under-the-curve values ranging from 82% to 92%. Bland-Altman plot showed high agreement between the methods. Conclusions: Comparisons between the Kscores and the traditional PLMI show increased accuracy with severity level and excellent agreement. The KickStrip is a valuable tool for PLMD testing for both clinical and research purposes.