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  - Kaufmann, Tobias
A1  - Holz, Elisa M.
A1  - Kübler, Andrea
T1  - Comparison of tactile, auditory, and visual modality for brain-computer interface use: a case study with a patient in the locked-in state
JF  - Frontiers in Human Neuroscience
N2  - This paper describes a case study with a patient in the classic locked-in state, who currently has no means of independent communication. Following a user-centered approach, we investigated event-related potentials (ERP) elicited in different modalities for use in brain-computer interface (BCI) systems. Such systems could provide her with an alternative communication channel. To investigate the most viable modality for achieving BCI based communication, classic oddball paradigms (1 rare and 1 frequent stimulus, ratio 1:5) in the visual, auditory and tactile modality were conducted (2 runs per modality). Classifiers were built on one run and tested offline on another run (and vice versa). In these paradigms, the tactile modality was clearly superior to other modalities, displaying high offline accuracy even when classification was performed on single trials only. Consequently, we tested the tactile paradigm online and the patient successfully selected targets without any error. Furthermore, we investigated use of the visual or tactile modality for different BCI systems with more than two selection options. In the visual modality, several BCI paradigms were tested offline. Neither matrix-based nor so-called gaze-independent paradigms constituted a means of control. These results may thus question the gaze-independence of current gaze-independent approaches to BCI. A tactile four-choice BCI resulted in high offline classification accuracies. Yet, online use raised various issues. Although performance was clearly above chance, practical daily life use appeared unlikely when compared to other communication approaches (e.g., partner scanning). Our results emphasize the need for user-centered design in BCI development including identification of the best stimulus modality for a particular user. Finally, the paper discusses feasibility of EEG-based BCI systems for patients in classic locked-in state and compares BCI to other AT solutions that we also tested during the study.
KW  - brain-computer interface
KW  - tactile auditory and visual modality
KW  - locked-in syndrome
KW  - user-centered design
KW  - end-user testing
KW  - assistive technology
Y1  - 2013
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-97079
ER  -