On ERPs detection in disorders of consciousness rehabilitation

Abstract

Disorders of Consciousness (DOC) like Vegetative State (VS), and Minimally Conscious State (MCS) are clinical conditions characterized by the absence or intermittent behavioral responsiveness. A neurophysiological monitoring of parameters like Event-Related Potentials (ERPs) could be a first step to follow-up the clinical evolution of these patients during their rehabilitation phase. Eleven patients diagnosed as VS (n = 8) and MCS (n = 3) by means of the JFK Coma Recovery Scale Revised (CRS-R) underwent scalp EEG recordings during the delivery of a 3-stimuli auditory oddball paradigm, which included standard, deviant tones and the subject own name (SON) presented as a novel stimulus, administered under passive and active conditions. Four patients who showed a change in their clinical status as detected by means of the CRS-R (i.e., moved from VS to MCS), were subjected to a second EEG recording session. All patients, but one (anoxic etiology), showed ERP components such as mismatch negativity (MMN) and novelty P300 (nP3) under passive condition. When patients were asked to count the novel stimuli (active condition), the nP3 component displayed a significant increase in amplitude (p = 0.009) and a wider topographical distribution with respect to the passive listening, only in MCS. In 2 out of the 4 patients who underwent a second recording session consistently with their transition from VS to MCS, the nP3 component elicited by passive listening of SON stimuli revealed a significant amplitude increment (p < 0.05). Most relevant, the amplitude of the nP3 component in the active condition, acquired in each patient and in all recording sessions, displayed a significant positive correlation with the total scores (p = 0.004) and with the auditory sub-scores (p < 0.00001) of the CRS-R administered before each EEG recording. As such, the present findings corroborate the value of ERPs monitoring in DOC patients to investigate residual unconscious and conscious cognitive function.

Preserved consciousness in vegetative and minimal conscious states: systematic review and meta-analysis

“…Of course, it is reasonable to assume that false positive results can occur with passive paradigms, but at present their frequency is unknown. However, serial assessments, although rarely performed, may increase the diagnostic yield and reveal signs of consciousness in passive and active paradigms in patients who initially are without such signs 11 15 25 40…”

The P300 in middle cerebral artery strokes or hemorrhages: Outcome predictions and source localization

“…The P300 has been shown to predict the outcome of patients in low responsive state (Daltrozzo et al, 2007) or coma (Morlet and Fischer, 2014). It can provide information on conscious and unconscious cognitive functions (Risetti et al, 2013).…”

Cognitive Processing in Non-Communicative Patients: What Can Event-Related Potentials Tell Us?

“…Nevertheless, the use of the P300 to distinguish between VS/UWS and MCS has shown contradictory results: some studies have found some differences in this ERP between both groups (Schnakers et al, 2008b; Cavinato et al, 2011; Risetti et al, 2013), while others did not (Kotchoubey et al, 2005; Perrin et al, 2006; Fischer et al, 2010; Real et al, 2016). Covert response to commands in VS/UWS patients has been reported with this ERP component (Chennu et al, 2013).…”