Information processing in patients in vegetative and minimally conscious states

Real, Ruben; Veser, Sandra; Erlbeck, Helena; Risetti, Monica; Vogel, Dominik; Müller, Friedemann; Kotchoubey, Boris; Mattia, Donatella; Kübler, Andrea

doi:10.1016/j.clinph.2015.07.020

Cited by 32 publications

(31 citation statements)

References 43 publications

(51 reference statements)

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“…ERP paradigms need to be further refined and tested in a larger sample of this patient group and also with genuine DOC patients before conclusions about their applicability for diagnosis can be drawn. Alterations have been suggested in the topography, latency and amplitude of ERPs in VS/UWS and MCS patients (Kotchoubey et al, 2005; Real et al, 2016). Our findings, although limited in their generalizability by the small sample size, allows us to suggest the possibility that, in conscious patients with localized damage, these potentials may be completely absent due to multiple factors.…”

Section: Discussionmentioning

confidence: 99%

“…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).…”

Section: Introductionmentioning

confidence: 99%

“…A recent study has shown a higher prevalence of the auditory P300 evoked by simple tones in an oddball paradigm in healthy subjects (HS) as compared to patients in VS and MCS, but this ERP component showed a low sensitivity to differentiate between VS/UWS and MCS patients (Real et al, 2016). Given the characteristic of LIS patients of presenting with a sub-cortical lesion keeping full consciousness and intact or nearly intact cognitive abilities, it is possible to hypothesize that such a test would be useful for detecting quickly and efficiently the presence of consciousness in these patients.…”

Section: Introductionmentioning

confidence: 99%

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

Lugo

Quitadamo

Bianchi

et al. 2016

Front. Hum. Neurosci.

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Event-related potentials (ERP) have been proposed to improve the differential diagnosis of non-responsive patients. We investigated the potential of the P300 as a reliable marker of conscious processing in patients with locked-in syndrome (LIS). Eleven chronic LIS patients and 10 healthy subjects (HS) listened to a complex-tone auditory oddball paradigm, first in a passive condition (listen to the sounds) and then in an active condition (counting the deviant tones). Seven out of nine HS displayed a P300 waveform in the passive condition and all in the active condition. HS showed statistically significant changes in peak and area amplitude between conditions. Three out of seven LIS patients showed the P3 waveform in the passive condition and five of seven in the active condition. No changes in peak amplitude and only a significant difference at one electrode in area amplitude were observed in this group between conditions. We conclude that, in spite of keeping full consciousness and intact or nearly intact cortical functions, compared to HS, LIS patients present less reliable results when testing with ERP, specifically in the passive condition. We thus strongly recommend applying ERP paradigms in an active condition when evaluating consciousness in non-responsive patients.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Lugo

Quitadamo

Bianchi

et al. 2016

Front. Hum. Neurosci.

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“…In active conditions, the patient was told either to keep a mental count of their own name presented (Hauger et al, ; Risetti et al, ; Schnakers et al, ) or to attentively listen “because there might be a change in voice speech” (Hauger et al, ; Schnakers et al, ). A more recent study merely used a two‐tone oddball paradigm with the instruction to count deviant tones in the active phase (Real et al, ). These studies succeeded in identifying some patients with positive results (i.e., larger P300s in active condition than in passive listening), and the respondents were more often in a minimally conscious state than in a vegetative state.…”

Section: Introductionmentioning

confidence: 99%

“…These studies succeeded in identifying some patients with positive results (i.e., larger P300s in active condition than in passive listening), and the respondents were more often in a minimally conscious state than in a vegetative state. A major concern is that, when applied to healthy cooperative subjects, most tested active ERP paradigms did not show statistically significant results in all individuals (Hauger et al, ; Real et al, ; Schnakers et al, ). More generally, the past literature about attention effects on P300 in healthy subjects reported group effects, with no guarantee of significant effects in every individual subject.…”

Section: Introductionmentioning

confidence: 99%

The auditory oddball paradigm revised to improve bedside detection of consciousness in behaviorally unresponsive patients

2017

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Active paradigms requiring subjects to engage in a mental task on request have been developed to detect consciousness in behaviorally unresponsive patients. Using auditory ERPs, the active condition consists in orienting patient's attention toward oddball stimuli. In comparison with passive listening, larger P300 in the active condition identifies voluntary processes. However, contrast between these two conditions is usually too weak to be detected at the individual level. To improve test sensitivity, we propose as a control condition to actively divert the subject's attention from the auditory stimuli with a mental imagery task that has been demonstrated to be within the grasp of the targeted patients: navigate in one's home. Twenty healthy subjects were presented with a two-tone oddball paradigm in the three following condition: (a) passive listening, (b) mental imagery, (c) silent counting of deviant stimuli. Mental imagery proved to be more efficient than passive listening to lessen P300 response to deviant tones as compared with the active counting condition. An effect of attention manipulation (oriented vs. diverted) was observed in 19/20 subjects, of whom 18 showed the expected P300 effect and 1 showed an effect restricted to the N2 component. The only subject showing no effect also proved insufficient engagement in the tasks. Our study demonstrated the efficiency of diverting attention using mental imagery to improve the sensitivity of the active oddball paradigm. Using recorded instructions and requiring a small number of electrodes, the test was designed to be conveniently and economically used at the patient's bedside.

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Brain–Computer Interfaces and Their Place in the Management of Disorders of Consciousness

Meys,

Thibaut,

Annen

2023

Coma and Disorders of Consciousness

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Information processing in patients in vegetative and minimally conscious states

Cited by 32 publications

References 43 publications

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

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

The auditory oddball paradigm revised to improve bedside detection of consciousness in behaviorally unresponsive patients

Brain–Computer Interfaces and Their Place in the Management of Disorders of Consciousness

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