@article{ErlbeckMochtyKuebleretal.2017,
  author    = {Erlbeck, Helena and Mochty, Ursula and K{\"u}bler, Andrea and Real, Ruben G. L.},
  title     = {Circadian course of the P300 ERP in patients with amyotrophic lateral sclerosis - implications for brain-computer interfaces (BCI)},
  series = {BMC Neurology},
  volume    = {17},
  journal   = {BMC Neurology},
  number    = {3},
  doi       = {10.1186/s12883-016-0782-1},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-157423},
  year      = {2017},
  abstract  = {Background: Accidents or neurodegenerative diseases like amyotrophic lateral sclerosis (ALS) can lead to progressing, extensive, and complete paralysis leaving patients aware but unable to communicate (locked-in state). Brain-computer interfaces (BCI) based on electroencephalography represent an important approach to establish communication with these patients. The most common BCI for communication rely on the P300, a positive deflection arising in response to rare events. To foster broader application of BCIs for restoring lost function, also for end-users with impaired vision, we explored whether there were specific time windows during the day in which a P300 driven BCI should be preferably applied. Methods: The present study investigated the influence of time of the day and modality (visual vs. auditory) on P300 amplitude and latency. A sample of 14 patients (end-users) with ALS and 14 healthy age matched volunteers participated in the study and P300 event-related potentials (ERP) were recorded at four different times (10, 12 am, 2, \& 4 pm) during the day. Results: Results indicated no differences in P300 amplitudes or latencies between groups (ALS patients v. healthy participants) or time of measurement. In the auditory condition, latencies were shorter and amplitudes smaller as compared to the visual condition. Conclusion: Our findings suggest applicability of EEG/BCI sessions in patients with ALS throughout normal waking hours. Future studies using actual BCI systems are needed to generalize these findings with regard to BCI effectiveness/efficiency and other times of day.},
  language  = {en}
}
@article{LugoQuitadamoBianchietal.2016,
  author    = {Lugo, Zulay R. and Quitadamo, Lucia R. and Bianchi, Luigi and Pellas, Fr{\´e}deric and Veser, Sandra and Lesenfants, Damien and Real, Ruben G. L. and Herbert, Cornelia and Guger, Christoph and Kotchoubey, Boris and Mattia, Donatella and K{\"u}bler, Andrea and Laureys, Steven and Noirhomme, Quentin},
  title     = {Cognitive Processing in Non-Communicative Patients: What Can Event-Related Potentials Tell Us?},
  series = {Frontiers in Human Neuroscience},
  volume    = {10},
  journal   = {Frontiers in Human Neuroscience},
  number    = {569},
  doi       = {10.3389/fnhum.2016.00569},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-165165},
  year      = {2016},
  abstract  = {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.},
  language  = {en}
}