Abstract Details

Title Evidence of Sympathetic Overactivity in Subjects with REM Behavior Disorder at Risk for Parkinson's Disease

Topic Sleep

Presentation(s) P6 - Poster Session 6 (5:30 PM-6:30 PM)

Poster/Presentation
Number 11-002

Objective 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.

Background 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.

Design/Methods

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.

Results

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).

Conclusions

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.
	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)	The institution of Pascal Sati has received research support from National Multiple Sclerosis Society. The institution of Pascal Sati has received research support from National Institutes of Health . The institution of Pascal Sati has received research support from Erwin Rautenberg Fondation. The institution of Pascal Sati has received research support from Department of Defense. Pascal Sati has received intellectual property interests from a discovery or technology relating to health care. Pascal Sati has received publishing royalties from a publication relating to health care.

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