title: The effect of multimodal and enriched feedback on SMR-BCI performance.
abstract: OBJECTIVE
  This study investigated the effect of multimodal (visual and auditory) continuous feedback with information about the uncertainty of the input signal on motor imagery based BCI performance. A liquid floating through a visualization of a funnel (funnel feedback) provided enriched visual or enriched multimodal feedback.
  
  
  METHODS
  In a between subject design 30 healthy SMR-BCI naive participants were provided with either conventional bar feedback (CB), or visual funnel feedback (UF), or multimodal (visual and auditory) funnel feedback (MF). Subjects were required to imagine left and right hand movement and were trained to control the SMR based BCI for five sessions on separate days.
  
  
  RESULTS
  Feedback accuracy varied largely between participants. The MF feedback lead to a significantly better performance in session 1 as compared to the CB feedback and could significantly enhance motivation and minimize frustration in BCI use across the five training sessions.
  
  
  CONCLUSIONS
  The present study demonstrates that the BCI funnel feedback allows participants to modulate sensorimotor EEG rhythms. Participants were able to control the BCI with the funnel feedback with better performance during the initial session and less frustration compared to the CB feedback.
  
  
  CONCLUSIONS
  The multimodal funnel feedback provides an alternative to the conventional cursorbar feedback for training subjects to modulate their sensorimotor rhythms.
authors.affiliation: Department of Psychology I, University of Würzburg, 97070 Würzburg, Germany. Electronic address: teresa.sollfrank@uni-wuerzburg.de.
authors.forename: T
authors.initials: T
authors.lastname: Sollfrank
authors.affiliation: Department of Computing Science, Glasgow University, Glasgow G12 8QQm, Scotland, United Kingdom. Electronic address: Andrew.Ramsay@glasgow.ac.uk.
authors.forename: A
authors.initials: A
authors.lastname: Ramsay
authors.affiliation: École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland. Electronic address: serafeim.perdikis@epfl.ch.
authors.forename: S
authors.initials: S
authors.lastname: Perdikis
authors.affiliation: Department of Computing Science, Glasgow University, Glasgow G12 8QQm, Scotland, United Kingdom. Electronic address: John.Williamson@glasgow.ac.uk.
authors.forename: J
authors.initials: J
authors.lastname: Williamson
authors.affiliation: Department of Computing Science, Glasgow University, Glasgow G12 8QQm, Scotland, United Kingdom. Electronic address: rod@dcs.gla.ac.uk.
authors.forename: R
authors.initials: R
authors.lastname: Murray-Smith
authors.affiliation: École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland. Electronic address: robert.leeb@epfl.ch.
authors.forename: R
authors.initials: R
authors.lastname: Leeb
authors.affiliation: École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland. Electronic address: jose.millan@epfl.ch.
authors.forename: J D R
authors.initials: JDR
authors.lastname: Millán
authors.affiliation: Department of Psychology I, University of Würzburg, 97070 Würzburg, Germany; Institute of Medical Psychology and Behavioural Neurobiology, University of Tübingen, 72074 Tübingen, Germany. Electronic address: andrea.kuebler@uni-wuerzburg.de.
authors.forename: A
authors.initials: A
authors.lastname: Kübler
mesh_terms: D000328:Adult; D062207:Brain-Computer Interfaces; D004569:Electroencephalography / Q000379:methods*; D056228:Feedback, Sensory / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010775:Photic Stimulation / Q000379:methods*; D011597:Psychomotor Performance / Q000502:physiology*; D055815:Young Adult
keywords: Brain–computer interfaces; EEG; Feedback; Multimodality; Sensorimotor rhythms