TY - JOUR A1 - Kaufmann, Tobias A1 - Herweg, Andreas A1 - Kübler, Andrea T1 - Toward brain-computer interface based wheelchair control utilizing tactually-evoked event-related potentials N2 - Background People with severe disabilities, e.g. due to neurodegenerative disease, depend on technology that allows for accurate wheelchair control. For those who cannot operate a wheelchair with a joystick, brain-computer interfaces (BCI) may offer a valuable option. Technology depending on visual or auditory input may not be feasible as these modalities are dedicated to processing of environmental stimuli (e.g. recognition of obstacles, ambient noise). Herein we thus validated the feasibility of a BCI based on tactually-evoked event-related potentials (ERP) for wheelchair control. Furthermore, we investigated use of a dynamic stopping method to improve speed of the tactile BCI system. Methods Positions of four tactile stimulators represented navigation directions (left thigh: move left; right thigh: move right; abdomen: move forward; lower neck: move backward) and N = 15 participants delivered navigation commands by focusing their attention on the desired tactile stimulus in an oddball-paradigm. Results Participants navigated a virtual wheelchair through a building and eleven participants successfully completed the task of reaching 4 checkpoints in the building. The virtual wheelchair was equipped with simulated shared-control sensors (collision avoidance), yet these sensors were rarely needed. Conclusion We conclude that most participants achieved tactile ERP-BCI control sufficient to reliably operate a wheelchair and dynamic stopping was of high value for tactile ERP classification. Finally, this paper discusses feasibility of tactile ERPs for BCI based wheelchair control. KW - Brain-computer interface KW - Event-related potentials KW - P300 KW - Tactile KW - Wheelchair KW - Dynamic stopping Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-110042 ER - TY - JOUR A1 - Strik, Werner K. A1 - Dierks, Thomas A1 - Franzek, Ernst A1 - Stöber, Gerald A1 - Maurer, Konrad T1 - P300 in Schizophrenia: Interactions between Amplitudes and Topography N2 - Low P300 amplitudes and topographical asymmetries have been reponed in schizophrenic patients, but reference-independent amplitude assessment failed to replicate reduced amplitudes. P300 amplitude is conventially assessed at midline electrodes (PZ), anti asymmetric topography as reported in schizophrenics, may conj'ound this measurement. We lnvestigated the possible Interaction between P300 ropography and assessments of amplitudes. ln 41 clinically stable schizophrenics and 31 normal controls, the generalfinding ofreduced amplitudes at the P'l electrode and topographical asymmetrles in the patient group were replicated. ln both groups, a.symmetries of the P300 field (lateralized peaks) reduced the standard amplitude assessment at the midline parletal electrode, but did not Qjfoct the reference-independent, global amplitude assessment. This shows thal asymmetry per se does not imply reduced field strength. in addition, in schizophreraics. but not in controls, there was a significcmt effect oftlae direction of asymmetry on both amplltude measures, amplitudes belng lower with increasing shift ofthe P300 peak to the right side. Considering also the slightly left-lateralized peaks in the normal controls. this suggests rhat only right lateralized P300 peaks upressfunctional deficits in schizophrenics, whereas left lateralized pealcs fall wlthin the physiological variability of the P3OO field. Tht refonnce-independent amplitude assessment is proposed for unambiguous amplitude assessment in order to better define the clinical, psychological and physiopathological mtaning of the P3OO alterations in schizophrenics. KW - Schizophrenie KW - Event-related potentials KW - P300 KW - P300 topography KW - Brain mappins KW - Schizophrenia Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-63351 ER -