Detecting Brain Activity Following a Verbal Command in Patients With Disorders of Consciousness.

Fuyan Wang,Haibo Di,Steven Laureys,Wangshan Huang,Shan Jing,Jing Wang,Nantu Hu,Lizette Heine,Aurore Thibaut,Xiaohua Hu,Yifan Yan,Caroline Schnakers

doi:10.3389/fnins.2019.00976

Abstract

BackgroundThe accurate assessment of patients with disorders of consciousness (DOC) is a challenge to most experienced clinicians. As a potential clinical tool, functional magnetic resonance imaging (fMRI) could detect residual awareness without the need for the patients’ actual motor responses.MethodsWe adopted a simple active fMRI motor paradigm (hand raising) to detect residual awareness in these patients. Twenty-nine patients were recruited. They met the diagnosis of minimally conscious state (MCS) (male = 6, female = 2; n = 8), vegetative state/unresponsive wakefulness syndrome (VS/UWS) (male = 17, female = 4; n = 21).ResultsWe analyzed the command-following responses for robust evidence of statistically reliable markers of motor execution, similar to those found in 15 healthy controls. Of the 29 patients, four (two MCS, two VS/UWS) could adjust their brain activity to the “hand-raising” command, and they showed activation in motor-related regions (which could not be discovered in the own-name task).ConclusionLongitudinal behavioral assessments showed that, of these four patients, two in a VS/UWS recovered to MCS and one from MCS recovered to MCS+ (i.e., showed command following). In patients with no response to hand raising task, six VS/UWS and three MCS ones showed recovery in follow-up procedure. The simple active fMRI “hand-raising” task can elicit brain activation in patients with DOC, similar to those observed in healthy volunteers. Activity of the motor-related network may be taken as an indicator of high-level cognition that cannot be discerned through conventional behavioral assessment.

Highlights

MATERIALS AND METHODSDuring clinical assessment of patients with disorders of consciousness (DOC), overt behaviors may be ambiguous or absent (Schnakers et al, 2009)
As to presentation of their own name, no activation was found in the supplementary motor cortex (SMA) or M1, some showed activation in the cerebellum, which is similar to the situation in healthy volunteers (Schutter and van Honk, 2005; Stoodley, 2012)
Longitudinal behavioral assessments showed that, of these four patients with positive activation, two in a VS/unresponsive wakefulness syndrome (UWS) evolved to minimally conscious state (MCS) and one from MCS evolved to MCS+

Summary

Introduction

During clinical assessment of patients with disorders of consciousness (DOC), overt behaviors may be ambiguous or absent (Schnakers et al, 2009). In these cases, functional neuroimaging paradigms can assist conventional behavioral assessment (Davey et al, 2000; Coleman et al, 2009; Stender et al, 2014). Recent functional magnetic resonance imaging (fMRI) studies have demonstrated preserved conscious awareness in some patients meeting the clinical criteria for a unresponsive wakefulness syndrome (UWS) (Laureys et al, 2010), using tasks that express “volitional” aspects of behavior, such as communicating “yes”/“no” responses by using mental imagery paradigms of “playing tennis” and navigating in one’s house (Giacino et al, 2002; Boly et al, 2007; Monti et al, 2010). As a potential clinical tool, functional magnetic resonance imaging (fMRI) could detect residual awareness without the need for the patients’ actual motor responses

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