OBJECTIVE: Night-to-night variability of periodic leg movements (PLMs) in restless legs syndrome (RLS) was examined to define the range of intra-subject values, impact upon diagnosing RLS, and clinical correlates. METHODS: Twenty RLS patients were monitored for 10-15 nights using a validated, tri-axial accelerometer worn on the ankle. RESULTS: The mean difference in PLMs index (PLMI) between the lowest and highest night was 25.1/h (range: 3.9-73.8). Inter-subject differences accounted for nearly five times the variance in PLMI relative to between nights within an individual. Based on a single night of recording, PLMI criterion thresholds of 5, 10, and 15/h were exceeded on approximately 70.1%, 51.9% and 34.1% of individual nights among these patients. Based on five randomly sampled nights of recordings, the likelihood that such thresholds were met on at least a single night increased to 91.2%, 80.8% and 62.7%, respectively. Women exhibited greater variability. CONCLUSIONS: Variability in PLMs within RLS subjects was substantial, yet individuals' characteristic PLM level represented a quantitative trait. Variability was unrelated to age or scores on scales of RLS severity, sleepiness, functional status, and mood. A larger number of recording nights increased the likelihood that any criterion was reached.
OBJECTIVE: Night-to-night variability of periodic leg movements (PLMs) in restless legs syndrome (RLS) was examined to define the range of intra-subject values, impact upon diagnosing RLS, and clinical correlates. METHODS: Twenty RLS patients were monitored for 10-15 nights using a validated, tri-axial accelerometer worn on the ankle. RESULTS: The mean difference in PLMs index (PLMI) between the lowest and highest night was 25.1/h (range: 3.9-73.8). Inter-subject differences accounted for nearly five times the variance in PLMI relative to between nights within an individual. Based on a single night of recording, PLMI criterion thresholds of 5, 10, and 15/h were exceeded on approximately 70.1%, 51.9% and 34.1% of individual nights among these patients. Based on five randomly sampled nights of recordings, the likelihood that such thresholds were met on at least a single night increased to 91.2%, 80.8% and 62.7%, respectively. Women exhibited greater variability. CONCLUSIONS: Variability in PLMs within RLS subjects was substantial, yet individuals' characteristic PLM level represented a quantitative trait. Variability was unrelated to age or scores on scales of RLS severity, sleepiness, functional status, and mood. A larger number of recording nights increased the likelihood that any criterion was reached.
Authors: Gerhard Weinreich; Sarah Terjung; Yi Wang; Stefanie Werther; Alberto Zaffaroni; Helmut Teschler Journal: Sleep Breath Date: 2017-08-18 Impact factor: 2.816
Authors: Valerie E Rogers; Paul R Gallagher; Carole L Marcus; Kwaku Ohene-Frempong; Joel T Traylor; Thornton B A Mason Journal: Sleep Med Date: 2012-07-25 Impact factor: 3.492
Authors: Christoforos D Giannaki; Paris Zigoulis; Christina Karatzaferi; Georgios M Hadjigeorgiou; Keith P George; Konstantinos Gourgoulianis; Yiannis Koutedakis; Ioannis Stefanidis; Giorgos K Sakkas Journal: J Clin Sleep Med Date: 2013-02-01 Impact factor: 4.062