TY  - JOUR
A1  - Lugo, Zulay R.
A1  - Quitadamo, Lucia R.
A1  - Bianchi, Luigi
A1  - Pellas, Fréderic
A1  - Veser, Sandra
A1  - Lesenfants, Damien
A1  - Real, Ruben G. L.
A1  - Herbert, Cornelia
A1  - Guger, Christoph
A1  - Kotchoubey, Boris
A1  - Mattia, Donatella
A1  - Kübler, Andrea
A1  - Laureys, Steven
A1  - Noirhomme, Quentin
T1  - Cognitive Processing in Non-Communicative Patients: What Can Event-Related Potentials Tell Us?
JF  - Frontiers in Human Neuroscience
N2  - 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.
KW  - P300
KW  - event-related potentials
KW  - locked-in syndrome
KW  - vegetative state
KW  - unresponsive wakefulness syndrome
KW  - minimally conscious state
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-165165
VL  - 10
IS  - 569
ER  - 
TY  - JOUR
A1  - Erlbeck, Helena
A1  - Kübler, Andrea
A1  - Kotchoubey, Boris
A1  - Veser, Sandra
T1  - Task instructions modulate the attentional mode affecting the auditory MMN and the semantic N400
JF  - Frontiers in Human Neuroscience
N2  - Event-related potentials (ERPs) have been proven to be a useful tool to complement clinical assessment and to detect residual cognitive functions in patients with disorders of consciousness. These ERPs are of ten recorded using passive or unspecific instructions. Patient data obtained this way are then compared to data from healthy participants, which are usually recorded using active instructions. The present study investigates the effect of attentive modulations and particularly the effect of activevs. passive instruction on the ERP components mismatch negativity (MMN) and N400. A sample of 18 healthy participants listened to three auditory paradigms: anoddball, aword priming, and a sentence paradigm. Each paradigm was presented three times with different instructions: ignoring auditory stimuli, passive listening, and focused attention on the auditory stimuli. After each task, the participants indicated their subjective effort. The N400 decreased from the focused task to the passive task, and was extinct in the ignore task. The MMN exhibited higher amplitudes in the focused and passive task compared to the ignore task. The data indicate an effect of attention on the supratemporal component of the MMN. Subjective effort was equally high in the passive and focused tasks but reduced in the ignore task. We conclude that passive listening during EEG recording is stressful and attenuates ERPs, which renders the interpretation of the results obtained in such conditions difficult.
KW  - ERP
KW  - priming
KW  - selective attention
KW  - event-related potentials
KW  - vigilance decrement
KW  - brain potentials
KW  - vegetative state
KW  - consciousness
KW  - component
KW  - predicts recovery
KW  - mismatch negativity
KW  - attention
KW  - instruction
KW  - N400
KW  - MMN
Y1  - 2014
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-115553
VL  - 8
IS  - 654
ER  -