@article{c4919b94692c4c1496266926610e667e,
title = "Impaired resting vagal tone in patients with functional movement disorders",
abstract = "Introduction The autonomic nervous system plays an integral role in the maintenance of homeostasis during times of stress. The functioning of the autonomic nervous system in patients with functional movement disorders (FMD) is of particular interest given the hypothesis that converted psychological stress plays a critical role in FMD disease pathogenesis. We sought to investigate autonomic nervous system activity in FMD patients by examining heart rate variability (HRV), a quantitative marker of autonomic function. Methods 35 clinically definite FMD patients and 38 age- and sex-matched healthy controls were hospitalized overnight for continuous electrocardiogram recording. Standard time and frequency domain measures of HRV were calculated in the awake and asleep stages. All participants underwent a thorough neuropsychological battery, including the Hamilton Anxiety and Depression scales and the Beck Depression Inventory. Results Compared to controls, patients with FMD exhibited decreased root mean square of successive differences between adjacent NN intervals (RMSSD) (p = 0.02), a marker of parasympathetic activity, as well as increased mean heart rate (p = 0.03). These measures did not correlate with the depression and anxiety scores included in our assessment as potential covariates. Conclusion In this exploratory study, patients with FMD showed evidence of impaired resting state vagal tone, as demonstrated by reduced RMSSD. This decreased vagal tone may reflect increased stress vulnerability in patients with FMD.",
keywords = "Autonomic nervous system, Conversion disorder, Functional movement disorders, Psychogenic movement disorders, Stress",
author = "Maurer, {Carine W.} and Liu, {Victoria D.} and Kathrin LaFaver and Rezvan Ameli and Tianxia Wu and Ryan Toledo and Epstein, {Steven A.} and Mark Hallett",
note = "Funding Information: This study was supported by the NINDS Intramural Program . We would like to thank Dr. Robert Brychta (NIDDK/NIH) and Peter Lauro (NINDS/NIH) for assistance with the Matlab program used for HRV analysis. We would like to acknowledge Elaine Considine, R.N., for her assistance with study coordination. Funding Information: Dr. Hallett is involved in the development of Neuroglyphics for tremor assessment, and has a collaboration with Portland State University to develop sensors to measure tremor. He serves as Chair of the Medical Advisory Board for and may receive honoraria and funding for travel from the Neurotoxin Institute . He may accrue revenue on US Patent #6,780,413 B2 (Issued: August 24, 2004): Immunotoxin (MAB-Ricin) for the treatment of focal movement disorders, and US Patent #7,407,478 (Issued: August 5, 2008): Coil for Magnetic Stimulation and methods for using the same (H-coil); in relation to the latter, he has received license fee payments from the NIH (from Brainsway) for licensing of this patent. Dr. Hallett{\textquoteright}s research at the NIH is largely supported by the NIH Intramural Program. Supplemental research funds have been granted by BCN Peptides, S.A. for treatment studies of blepharospasm, Medtronics, Inc. , for studies of deep brain stimulation, Parkinson Alliance for studies of eye movements in Parkinson{\textquoteright}s disease, UniQure for a clinical trial of AAV2-GDNF for Parkinson Disease, Merz for treatment studies of focal hand dystonia, and Allergan for studies of methods to inject botulinum toxins. Publisher Copyright: {\textcopyright} 2016 Copyright: Copyright 2017 Elsevier B.V., All rights reserved.",
year = "2016",
month = sep,
day = "1",
doi = "10.1016/j.parkreldis.2016.06.009",
language = "English (US)",
volume = "30",
pages = "18--22",
journal = "Parkinsonism and Related Disorders",
issn = "1353-8020",
publisher = "Elsevier BV",
}