title: Online use of error-related potentials in healthy users and people with severe motor impairment increases performance of a P300-BCI.
abstract: OBJECTIVE
  To investigate whether error-related potentials can be used to increase information transfer rate of a P3 brain-computer interface (BCI) in healthy and motor-impaired individuals.
  
  
  METHODS
  Extraction and classification of the error-related potential was performed offline on data recorded from six amyotrophic lateral sclerosis (ALS) patients. An online study with 17 healthy and six motor impaired participants followed, using a modified P3 speller to provide explicit feedback of spelled letters. On recognition of error-related potentials, the interface informed users that the incorrect letter was automatically deleted.
  
  
  RESULTS
  The offline cross-validation estimate of P3 speller data of six ALS patients increased bit rate by 0.44 bit/trial. During online copy spelling, the participants increased their bit rate by 0.52 bit/trial with the error correction system (ECS). Some participants performed free spelling and were able to increase their bit rate. Finally, we demonstrated that healthy participants could increase their bit rate by using a classifier pre-trained on other users' data.
  
  
  CONCLUSIONS
  Error-related potentials as a secondary source of information can be used to increase overall bit rate in a P3 BCI.
  
  
  CONCLUSIONS
  The method should be made available to any patient using the P3 BCI for communication.
authors.affiliation: Wilhelm-Schickard Institute of Computer Science, University of Tübingen, Sand 13, Tübingen 72076, Germany. spueler@informatik.uni-tuebingen.de
authors.forename: Martin
authors.initials: M
authors.lastname: Spüler
authors.forename: Michael
authors.initials: M
authors.lastname: Bensch
authors.forename: Sonja
authors.initials: S
authors.lastname: Kleih
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Rosenstiel
authors.forename: Martin
authors.initials: M
authors.lastname: Bogdan
authors.forename: Andrea
authors.initials: A
authors.lastname: Kübler
mesh_terms: D000328:Adult; D000690:Amyotrophic Lateral Sclerosis / Q000503:physiopathology*; D001931:Brain Mapping / Q000379:methods; D016022:Case-Control Studies; D003143:Communication Devices for People with Disabilities; D004566:Electrodes; D004569:Electroencephalography; D018913:Event-Related Potentials, P300 / Q000502:physiology*; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019957:Motor Skills Disorders / Q000503:physiopathology*; D009862:Online Systems; D015203:Reproducibility of Results; D014584:User-Computer Interface