TY - JOUR A1 - Simon, Nadine A1 - Käthner, Ivo A1 - Ruf, Carolin A. A1 - Pasqualotto, Emanuele A1 - Kübler, Andrea A1 - Halder, Sebastian T1 - An auditory multiclass brain-computer interface with natural stimuli: Usability evaluation with healthy participants and a motor impaired end user JF - Frontiers in Human Neuroscience N2 - Brain-computer interfaces (BCIs) can serve as muscle independent communication aids. Persons, who are unable to control their eye muscles (e.g., in the completely locked-in state) or have severe visual impairments for other reasons, need BCI systems that do not rely on the visual modality. For this reason, BCIs that employ auditory stimuli were suggested. In this study, a multiclass BCI spelling system was implemented that uses animal voices with directional cues to code rows and columns of a letter matrix. To reveal possible training effects with the system, 11 healthy participants performed spelling tasks on 2 consecutive days. In a second step, the system was tested by a participant with amyotrophic lateral sclerosis (ALS) in two sessions. In the first session, healthy participants spelled with an average accuracy of 76% (3.29 bits/min) that increased to 90% (4.23 bits/min) on the second day. Spelling accuracy by the participant with ALS was 20% in the first and 47% in the second session. The results indicate a strong training effect for both the healthy participants and the participant with ALS. While healthy participants reached high accuracies in the first session and second session, accuracies for the participant with ALS were not sufficient for satisfactory communication in both sessions. More training sessions might be needed to improve spelling accuracies. The study demonstrated the feasibility of the auditory BCI with healthy users and stresses the importance of training with auditory multiclass BCIs, especially for potential end-users of BCI with disease. KW - P300 KW - EEG KW - auditory BCI KW - brain-computer interface KW - communication KW - ALS Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-126450 VL - 8 IS - 1039 ER - TY - JOUR A1 - Halder, Sebastian A1 - Ruf, Carolin Anne A1 - Furdea, Adrian A1 - Pasqualotto, Emanuele A1 - De Massari, Daniele A1 - van der Heiden, Linda A1 - Bogdan, Martin A1 - Rosenstiel, Wolfgang A1 - Birbaumer, Niels A1 - Kübler, Andrea A1 - Matuz, Tamara T1 - Prediction of P300 BCI Aptitude in Severe Motor Impairment JF - PLoS ONE N2 - Brain-computer interfaces (BCIs) provide a non-muscular communication channel for persons with severe motor impairments. Previous studies have shown that the aptitude with which a BCI can be controlled varies from person to person. A reliable predictor of performance could facilitate selection of a suitable BCI paradigm. Eleven severely motor impaired participants performed three sessions of a P300 BCI web browsing task. Before each session auditory oddball data were collected to predict the BCI aptitude of the participants exhibited in the current session. We found a strong relationship of early positive and negative potentials around 200 ms (elicited with the auditory oddball task) with performance. The amplitude of the P2 (r = −0.77) and of the N2 (r = −0.86) had the strongest correlations. Aptitude prediction using an auditory oddball was successful. The finding that the N2 amplitude is a stronger predictor of performance than P3 amplitude was reproduced after initially showing this effect with a healthy sample of BCI users. This will reduce strain on the end-users by minimizing the time needed to find suitable paradigms and inspire new approaches to improve performance. KW - amyothropic lateral sclerosis KW - electrode potentials KW - electroencephalography KW - event-related potentials KW - functional magnetic imaging KW - human performance KW - man-computer interface KW - topography Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-97268 ER -