Heart Rate Variability in evaluation of autonomic dysfunction in idiopathic REM-sleep behaviour disorder

Abstract

Introduction.Nearly 80% of people diagnosed with idiopathic REM sleep behaviour disorder (iRBD) via video-polysomnography (v-PSG) are expected to be in the prodromal stage of an alpha-synucleinopathy. Signs of autonomic dysfunction can appear earlier than motor or cognitive alpha-synucleinopathy symptoms. Heart Rate Variability (HRV) can potentially be an objective measurement of autonomic dysfunction, and furthermore can be obtained directly from v-PSG.Objectives. The aim of this study was to evaluate dysautonomia in iRBD subjects using HRV obtained during different sleep stages and wakefulness from v-PSG. Material and methods.Subjects positively screened by an RBD screening questionnaire (RBD-SQ) underwent v-PSG to diagnose RBD. HRV obtained from v-PSG recordings was correlated to dysautonomia evaluated from a Non-Motor Symptoms Scale (NMSS) questionnaire. Optimal cut-off values of HRV parameters to predict dysautonomia were calculated using receiver operating characteristics (ROC) -area under the curve (AUC) analysis. The effect of confounder variables was predicted with binomial logistic regression and multiple regression analyses.Results. Out of 72 positively screened subjects, 29 subjects were diagnosed as iRBD (mean age 66 ± 7.7 years) by v-PSG. Eighty--three per cent of the iRBD subjects in our cohort were at the time of diagnosis classified as having possible or probable prodromal Parkinson's Disease (pPD) compared to zero subjects being positively screened in the control group. The iRBD-positive subjects showed significant inverse correlations of NMSS score, particularly to log low-frequency (LF) component of HRV during wakefulness: r = -0.59 (p = 0.001). Based on ROC analysis and correlation between NMSS score, log LF during wakefulness (AUC 0.74, cut-off 4.69, sensitivity 91.7%, specificity 64.7%, p = 0.028) was considered as the most accurate predictor of dysautonomia in the iRBD group. Apnoea-hypopnoea index (AHI) negatively predicted dysautonomia in the iRBD group. None of the HRV components was able to predict the presence of iRBD in the full cohort. Age, gender, and PSG variables were significant confounders of HRV prediction.Conclusions. The presented study did not confirm the possibility of using HRV from v-PSG records of patients with iRBD to predict dysautonomia expressed by questionnaire methods. This is probably due to several confounding factors capable of influencing HRV in such a cohort.

Characterization of Sleep Structure and Autonomic Dysfunction in REM Sleep Behavior Disorder

“…Standard, window-based HRV methods have been already used in this field [20], [21], [22], [23] but they present some limitations due to the uneven sampling of the tachogram, which usually requires resampling by interpolating functions, thus overlooking the intrinsic point process nature of the RR interval series, and to the lack of a goodness-of-fit metric when parametric approaches (e.g., autoregressive estimates) are considered. Importantly, none of the existing methods provide an instantaneous estimate of HR and RR interval variance, thus requiring the analysis of long signal segments, typically longer than five minutes, which is cumbersome in this application, as some sleep stages could exhibit a shorter duration and faster dynamics.…”

Detection of prodromal Parkinson’s disease using a urine proteomics panel and machine learning

“…Asymptomatic LRRK2 carriers were recruited from first degree blood relatives of patients who are attending the movement disorders clinic at the National Hospital for Neurology and Neurosurgery, Queen Square, UK and known to be carriers for the LRRK2 G2019S mutation. In Kosice, participants were identified from a prospective data registry and a multistage screening for iRBD (PDBIOM study), which was diagnosed based on one or two nights of video-polysomnography (PSG) 53,54 . In addition to extensive demographic and clinical details (as outlined below), dopamine transporter scintigraphy (DaT scan), as well as calculated probability of prodromal Parkinson´s disease (pPD) based on the updated MDS criteria 55 as reported previously 53 were recorded and assessed.…”