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Abstract Details

Evidence of Sympathetic Overactivity in Subjects with REM Behavior Disorder at Risk for Parkinson's Disease
P6 - Poster Session 6 (5:30 PM-6:30 PM)
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.

Michele Tagliati, MD, FAAN (Cedars-Sinai Medical Center)
Dr. Tagliati has received publishing royalties from a publication relating to health care.
No disclosure on file
Helia Maghzi, MD (Cedars sinai) Dr. Maghzi has nothing to disclose.
No disclosure on file
Elliot J. 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.
No disclosure on file
No disclosure on file
No disclosure on file
Pascal Sati (Cedars Sinai) No disclosure on file