S84 Abstracts of 4th International Congress of WASM & 5th Conference of CSS / Sleep Medicine 12, Suppl. 1 (2011) S1–S130 Results: TH, not counterbalanced by DA, induces RLS symptoms. As TH increases in early evening RLS symptoms are higher at that time. Conclusion: Imbalance between TH and DA is central to RLS pathophysiol- ogy. Acknowledgements: We are much indebted to Dr Arthur S. Walters, Profes- sor of Neurology Vanderbilt School of Medicine, Nashville, Tennesee, USA, for helpful criticism of the manuscript and kind attention. T-L-095 MULTIPLE SCLEROSIS AND RESTLESS LEGS SYNDROME IN MIDDLE-AGE WOMEN Yanping Li 1 , Kassandra L. Munger 2 , Salma Batool-Anwar 3 , Alberto Ascherio 2 , Xiang Gao 2 . 1 The Channing Laboratory, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, United States; 2 Departments of Nutrition, Harvard School of Public Health, United States; 3 Division of Sleep Medicine, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, United States Introduction and Objectives: Significant associations between multiple sclerosis (MS) and restless legs syndrome (RLS) have been reported in previous case-controls studies, but these studies have been small. We, therefore, assessed the relationship between MS and RLS in a large cohort of middle-aged women. Materials and Methods: This is a cross-sectional study including 65,544 women (aged 41-58 years) participating in Nurses Health Study II. Women with diabetes and arthritis were excluded as these conditions can mimic RLS. Participants were considered to have RLS if they met four RLS diagnostic criteria recommended by the International RLS Study Group and had restless legs ≥5 times/month. Severe RLS was defined as having RLS more than 15 times per month. MS was self-reported and confirmed by their neurologist or by our study neurologist after medical record review. Multivariable logis- tic regression models were used to analyze the relation between MS and RLS, with adjustment for age, ancestry, latitude of residence, current BMI and BMI at age 18, physical activity, menopausal status, smoking, use of vitamin D supplement, analgesics, alcohol, folate, oral contraceptive, antidepressant, and history of stroke, MI and hypertension. Results: After adjusting for potential confounders, women with MS were found to have higher odds of RLS (odds ratio [OR]=2.67, 95% confident interval [CI]: 1.85-3.86) and severe RLS (OR=4.0, 95%CI: 2.58-6.22) compared to those without MS. We did not observe significant associations between MS duration and likelihood of RLS or severe RLS. The adjusted OR for RLS was 2.99 (95% CI 1.57-5.68) for women with MS for 0.1-5.0 years, 2.39 (95%CI: 1.30-4.41) for 5.1-10.0 years, and 2.73 (95%CI: 1.44-5.17) for 10+ years as compared to participants without MS. The associations between MS and RLS persisted in subgroup analysis according to age, obesity, and sleep duration. Conclusion: Women with MS are more likely to have RLS, especially severe RLS, relative to those without MS. T-L-096 NOCTURNAL MOVEMENT STUDY DURING SLEEP WITH CLASSIC ANALYSIS SYSTEM AND WITH A METHOD BASED ON VIDEO ANALYSIS Giacomo Della Marca 1 , Serena Dittoni 1 , Michele Scatena 1 , Gioacchino Mennuni 2 . 1 Neuroscience Departement Catholic University of Rome, Italy; 2 Sleep Laboratory of Complesso Integrato Columbus Rome, Italy Introduction and Objectives: Study nocturnal movements during sleep using a combined polysomnography and video analysis method. Materials and Methods: Five patients were studied with nocturnal polysomnography in sleep laboratory and actigraphy. Movements were studied using offline video analyses with a software system composed by: Manycam, WebcamXP, Zoneminder, Zoneminder Analyzer (ZMA), Actiwatch Activity & Sleep Analysis 7. The sleep stages and the major body movements were classified according to the AAMS Criteria. The time spent in each position and the sleep hours index were calculated. The video analisys was performed with combined use of Manycam and WebcamXP using an IP virtual camera. The ZMA provided data by video analysis performed with Zoneminder to obtain a format compatible with Actigraphy Analysis soft- ware. Zoneminder reveals the differences of video frame input, quantifies them and then stores them in an SQL database. ZMA divides the time in epochs of X seconds and calculates for these epochs values compatible with those obtained through actigraphic analysis using the database data. The obtained data are transformed in a legible format by SW Actiwatch Activity & Sleep Analysis 7. Results: The video analysis offline offers an approach to study the motion during sleep, not always visible with the classic video system and with surface EMG electrodes. This system permits an analysis of body movements of the limbs and the face. The Manycam and WebcamXP system is a more complete characterization of the macrostructure of sleep, visual analysis of body movements, spectral analysis of EMG and Actigraphy Analyses. Conclusion: This method has been used in studies of: patients recovering in intensive care unit and with altered consciousness; patients affected by movements disturbances during sleep; and animals. T-L-097 PERIODIC LEG MOVEMENTS, NASAL CPAP AND EXPIRATORY LOAD Woohee Seo 1 , Christian Guilleminault 2 . 1 Stanford University Sleep Medicine Div and South Korea, United States; 2 Stanford University School of Medicine, Department of Psychiatry and Behavior Science, Division of Sleep Medicine, United States Introduction and Objectives: Periodic limb movements during sleep (PLMS) appear during nasal CPAP titration. We studied 97 successively monitored patients during polysomnography performed during nasal PAP titration with presence of PLMS. Materials and Methods: PLMS were monitored and scored following AASM guidelines. Simultaneously with monitoring of leg EMG we recorded other EMG including those of inspiratory and expiratory muscles. The relationship between apnea and hypopneas and any periodic EMG discharge during nasal-PAP titration was also temporally determined. The temporal relation- ship of periodic EMG bursts seen in inspiratory and expiratory muscles and legs was determined: To be considered as “related” the two EMG (leg and abdominal muscles) bursts must have been starting in same time and overlapping in duration. Results: PLM analyses showed that the mean peak interval between two EMG leg discharges was 24±4 seconds for the total group. Leg EMG discharges were associated with a sympathetic activation (finger plethys- mography curve) in 95±2.2% and in 95±3% with change of the sleep EEG. Expiratory muscle EMG discharges were related to increase in PAP pressure and PLMS were associated with simultaneous expiratory muscle EMG discharge. 55 subjects treated with nasal CPAP (n=82/97) and 17/17 subjects treated with bilevel were still presenting PLM despite disappear- ance of AASM defined hypopneas, but PLMS disappeared with elimination of “flow limitation”, and cycling-alternating-pattern phase A2 and A3 which requested higher PAP pressure. Conclusion: 1) Disappearance of AASM defined hypopneas does not control abnormal breathing and PLMS. 2) PLMS are part of a muscle activation involving active contraction of expiratory muscles. This active contraction of expiratory and leg muscles disappeared with PAP pressure needed to control not hypopneas but flow limitation associated with active expiration during sleep. 3) Are “isolated” PLMS related to periodic muscle discharges of un-studied muscle groups particularly respiratory? T-L-098 POLYSOMNOGRAPHICALLY VALIDATED REM SLEEP BEHAVIOUR DISORDER IN RESTLESS LEGS SYNDROME: FREQUENCY AND ASSOCIATED FACTORS Friederike Sixel-Döring, Ellen Trautmann, Monica Canelo. Paracelsus-Elena-Klinik, Germany Introduction and Objectives: Due to leg movements in sleep, patients with RLS may show abnormal motor behaviours during sleep which may be dif- ficult to differentiate from RBD by taking the patient’s and/or bedpartner’s history. We investigated the frequency of REM sleep behaviour disorder (RBD) in Restless Legs Syndrome (RLS) and analyzed associated factors. Materials and Methods: Video-supported polysomnography (vPSG), com- parative statistical analysis of PSG, demographic, clinical and medication data. RBD was defined according to polysomnographic ICSD-2 criteria. Results: 286 consecutive RLS patients were investigated with vPSG. 20 patients were excluded from further analysis as they showed no REM sleep during vPSG recording. RBD was diagnosed in 12 of the remaining 266 RLS patients (5%). Violent behaviour was not diagnosed in any case, in some cases motor behaviour could not be differentiated from PLMS by history.