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Abstract Details

Evidence of Sympathetic Overactivity in Subjects with REM Behavior Disorder at Risk for Parkinson's Disease
Sleep
P6 - Poster Session 6 (5:30 PM-6:30 PM)
11-002
While the nature of RBD is not completely understood, there is evidence that enhancement of noradrenergic activity may play a causative role, as suggested by evidence of persistent tonic discharge of locus coeruleus (LC) and RBD-triggering action of selective norepinephrine reuptake inhibitors. 
To evaluate sympathetic nervous system (SNS) activity in subjects with REM sleep behavior disorder (RBD) at risk of Parkinson's disease, using imaging and autonomic functions markers.

Subjects >50 years old with RBD with at least one pre-motor PD symptom (hyposmia, constipation, depression) were tested with a battery of autonomic evaluations including SCOPA-AUT questionnaire, cardiac MIBG scintigraphy, Heart Rate Variability (HRV) and neuromelanin sensitive MRI (NSMRI) of LC and substantia nigra (SN). Analyzed variables included: 1) for MIBG, late heart/mediastinum (H/M) ratio and washout ratio (WR); 2) for HRV, time and frequency domain measures; 3) for NSMRI, contrast-to-noise ratio (CNR) between LC and pons and between substantia nigra (SN) and cerebral peduncles. Results were compared with available normative ranges.

14 subjects (11M, age 66.2±8.2) were enrolled. Average total SCOPA-AUT score was increased (12.1±6.7 vs 8.8±5.4), with gastrointestinal (2.4±2.1 vs 1.4±1.6), urinary (5.4±2.7 vs 3.9±2.4) and cardiovascular (0.86±1.10 vs 0.3±0.6) scores above normal ranges. MIBG late H/M ratio was reduced (1.45±0.31) with increased WR (33.0±14.8). HRV results showed enhanced sympathetic and low parasympathetic activity both in time (SDNN 106.8±73.2ms; RMSSD 21.9±10.9ms; PNN50% 6.7±8.4%) and frequency domain (LF/HF 3.4±1.8). NMSMRI showed high LC CNR (right 3.26±1.9 vs 2.08±0.5; left 2.95±0.9 vs 2.79±0.5). SN CNR was high (Medial 6.24±1.9 vs 4.57±0.8; Central 6.26±1.6 vs 3.43±0.6; Lateral 3.44±2.1 vs 3.05±0.5) and MDS-UPDRS motor scores were low (2.9±3.3).

RBD subjects at risk for PD show abnormal autonomic scores, which appears to be driven by SNS overactivity, as suggested by increased MIBG WR, elevated LF/HF HRV ratios and increased LC and SN NSMRI signal.

Authors/Disclosures
Michele Tagliati, MD, FAAN (Cedars-Sinai Medical Center)
PRESENTER
Dr. Tagliati has received publishing royalties from a publication relating to health care.
Michele Lima Gregorio, PhD (Cedars-Sinai Medical Center) Dr. Gregorio has nothing to disclose.
Helia Maghzi, MD (Cedars sinai) Dr. Maghzi has nothing to disclose.
Gloria Obialisi (Cedars-Sinai Medical Center) Gloria Obialisi has nothing to disclose.
Elliot James Hogg, MD (Cedars-Sinai Medical Center) Dr. Hogg has nothing to disclose.
Camille Malatt, MD (Cedars-Sinai Movement Disorders) Dr. Malatt has nothing to disclose.
Echo Tan, MD (Cedars Sinai Medical Center) Dr. Tan has received personal compensation in the range of $5,000-$9,999 for serving on a Speakers Bureau for Allergan.
Roy Artal, MD Dr. Artal has received personal compensation in the range of $5,000-$9,999 for serving on a Speakers Bureau for Jazz Pharmaceuticals. Dr. Artal has received personal compensation in the range of $10,000-$49,999 for serving as an Expert Witness for Private Parties. The institution of Dr. Artal has received research support from Jazz Pharma. The institution of Dr. Artal has received research support from Axsome. The institution of Dr. Artal has received research support from Suven.
Michael Shehata, MD Dr. Shehata has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Abbott.
Brian Renner Brian Renner has nothing to disclose.
Pascal Sati, PhD (Cedars Sinai) The institution of Dr. Sati has received research support from National Multiple Sclerosis Society. The institution of Dr. Sati has received research support from National Institutes of Health. Dr. Sati has received intellectual property interests from a discovery or technology relating to health care.