Training leads to increased auditory brain-computer interface performance of end-users with motor impairments.
OBJECTIVE
Auditory brain-computer interfaces are an assistive technology that can restore communication for motor impaired end-users. Such non-visual brain-computer interface paradigms are of particular importance for end-users that may lose or have lost gaze control. We attempted to show that motor impaired end-users can learn to control an auditory speller on the basis of event-related potentials.


METHODS
Five end-users with motor impairments, two of whom with additional visual impairments, participated in five sessions. We applied a newly developed auditory brain-computer interface paradigm with natural sounds and directional cues.


RESULTS
Three of five end-users learned to select symbols using this method. Averaged over all five end-users the information transfer rate increased by more than 1800% from the first session (0.17 bits/min) to the last session (3.08 bits/min). The two best end-users achieved information transfer rates of 5.78 bits/min and accuracies of 92%.


CONCLUSIONS
Our results show that an auditory BCI with a combination of natural sounds and directional cues, can be controlled by end-users with motor impairment. Training improves the performance of end-users to the level of healthy controls.


CONCLUSIONS
To our knowledge, this is the first time end-users with motor impairments controlled an auditory brain-computer interface speller with such high accuracy and information transfer rates. Further, our results demonstrate that operating a BCI with event-related potentials benefits from training and specifically end-users may require more than one session to develop their full potential.
Institute of Psychology, University of Würzburg, Marcusstr. 9-11, 97070 Würzburg, Germany; Department of Rehabilitation for Brain Functions, Research Institute of National Rehabilitation Center for Persons with Disabilities, Tokorozawa, 359-8555 Saitama, Japan. Electronic address: sebastian.halder@uni-wuerzburg.de.
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Halder
Institute of Psychology, University of Würzburg, Marcusstr. 9-11, 97070 Würzburg, Germany.
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Käthner
Institute of Psychology, University of Würzburg, Marcusstr. 9-11, 97070 Würzburg, Germany.
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Kübler
D000161:Acoustic Stimulation / Q000379:methods*; D000368:Aged; D062207:Brain-Computer Interfaces; D018913:Event-Related Potentials, P300 / Q000502:physiology*; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019957:Motor Skills Disorders / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology; D011214:Practice, Psychological
Assistive technology; Brain–computer interfaces; Communication; End-user evaluation