The Timecourse of Electrophysiological Brain-Heart Interaction in DoC Patients.

Francesco Riganello,Antonio Cerasa,Valentina Ruggiero,Lucia Francesca Lucca,Maria Ursino,Miriam Russo,Camillo Porcaro,Martina Vatrano,Simone Carozzo

doi:10.3390/brainsci11060750

Abstract

Disorders of Consciousness (DOC) are a spectrum of pathologies affecting one’s ability to interact with the external world. Two possible conditions of patients with DOC are Unresponsive Wakefulness Syndrome/Vegetative State (UWS/VS) and Minimally Conscious State (MCS). Analysis of spontaneous EEG activity and the Heart Rate Variability (HRV) are effective techniques in exploring and evaluating patients with DOC. This study aims to observe fluctuations in EEG and HRV parameters in the morning/afternoon resting-state recording. The study enrolled 13 voluntary Healthy Control (HC) subjects and 12 DOC patients (7 MCS, 5 UWS/VS). EEG and EKG were recorded. PSDalpha, PSDtheta powerband, alpha-blocking, alpha/theta of the EEG, Complexity Index (CI) and SDNN of EKG were analyzed. Higher values of PSDalpha, alpha-blocking, alpha/theta and CI values and lower values of PSD theta characterized HC individuals in the morning with respect to DOC patients. In the afternoon, we detected a significant difference between groups in the CI, PSDalpha, PSDtheta, alpha/theta and SDNN, with lower PSDtheta value for HC. CRS-R scores showed a strong correlation with recorded parameters mainly during evaluations in the morning. Our finding put in evidence the importance of the assessment, as the stimulation of DOC patients in research for behavioural response, in the morning.

Highlights

Disorders of Consciousness (DOC) are a spectrum of pathologies affecting one’s ability to interact with the external world
The DOC cover a broad population of very heterogeneous pathologies with diverse etiologies, injuries, and outcomes, making it hard to distinguish in the clinical practice between the different levels of consciousness [6], leading the examiners to a possible misdiagnosis [13,14,15,16]
We found that the alpha/theta ratio was higher in Healthy Control (HC) than DOC and higher in Minimally Conscious State (MCS)

Summary

Introduction

Disorders of Consciousness (DOC) are a spectrum of pathologies affecting one’s ability to interact with the external world. Consciousness is commonly defined by wakefulness (i.e., the presence of spontaneous periods of opening the eyes) and awareness (i.e., the ability for a subject to respond to the internal/external stimuli in an integrated way). The first is characterized by a spontaneous opening of the eyes and no sign of consciousness but reflexive responses to external stimuli [11,12]; the second condition exhibits minimal but discernible signs of non-reflex behaviours which occur reproducibly (yet inconsistently) as a response to visual, auditory, tactile, or noxious stimuli. The difficulty in assessing the consciousness level of UWS patients often depends on a subjective interpretation of the observed spontaneous and volitional behaviour [19]. A critical challenge in clinical practice is minimizing the diagnostic error to make a correct prognosis, the appropriate treatments, and facilitate end-of-life decisions [23,24]. DOC patients’ behavioural fluctuation can significantly impact diagnostic accuracy [25]

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