SLEEP ARCHITECTURE AND LEG MOVEMENT ACTIVITY DURING SLEEP IN PATIENTS WITH MULTIPLE SCLEROSIS

Abstract Introduction Although sleep in patients with Multiple Sclerosis (MS) has been investigated in several studies using subjective measures, objective sleep data collected using polysomnography (PSG) are still scanty and often divergent. We herein present the largest study to date evaluating sleep architecture and total leg movement activity during sleep (LMS) in patients with MS. Methods We collected PSG recordings from 80 patients affected by multiple sclerosis (MS, 48.1±10.61yo 67.5% females), and 60 age and gender matched healthy control subjects (HC, 48.5±17.20 yo, 56% females). Group differences were computed using non-parametric statistics for all traditional sleep architecture parameters, LMS, short-interval (SILMS), periodic (PLMS), isolated LMS (ISOLMS) indices and duration, inter-movement interval (IMI) graphs and time-of-night distribution of LMS. Results Patients with MS showed a significantly decreased total sleep period, an increased number of awakenings and stages shifts per hour of sleep, and an increased representation of stage 1 (min and %) compared to the HC group; 26 (32.5%) MS patients had PLMS ≥15/hour versus 8 (13.3%) HC subjects. On average, the comparison between MS and HC groups yielded significant results in terms of an increase in LMS, PLMS, SILMS and ISOLMS indices but not durations. Moreover, MS patients displayed a higher periodicity index, an increased PLMS activity at all inter-movement intervals considered and their PLMS time-of-night distribution revealed that the PLMS increase was stable over the course of the night. Conclusion Sleep continuity is significantly impaired in patients with MS. Moreover, MS patients also an increased total LMS activity, including PLMS, which may contribute to disrupt sleep continuity. A disinhibition of lower spinal network due to cervical or supraspinal MS lesions might be implicated in the mechanisms underlying this latter finding. Support The Employer Department of Neurology, Regional Hospital Lugano (EOC), Lugano, Switzerland receives financial support from Teva, Merck Serono, Biogen Idec, Bayer Schering, Genzyme, Roche and Novartis. The submitted work is not related to these agreements.