title: Sequenced subjective accents for brain-computer interfaces.
abstract: Subjective accenting is a cognitive process in which identical auditory pulses at an isochronous rate turn into the percept of an accenting pattern. This process can be voluntarily controlled, making it a candidate for communication from human user to machine in a brain-computer interface (BCI) system. In this study we investigated whether subjective accenting is a feasible paradigm for BCI and how its time-structured nature can be exploited for optimal decoding from non-invasive EEG data. Ten subjects perceived and imagined different metric patterns (two-, three- and four-beat) superimposed on a steady metronome. With an offline classification paradigm, we classified imagined accented from non-accented beats on a single trial (0.5 s) level with an average accuracy of 60.4% over all subjects. We show that decoding of imagined accents is also possible with a classifier trained on perception data. Cyclic patterns of accents and non-accents were successfully decoded with a sequence classification algorithm. Classification performances were compared by means of bit rate. Performance in the best scenario translates into an average bit rate of 4.4 bits min(-1) over subjects, which makes subjective accenting a promising paradigm for an online auditory BCI.
authors.affiliation: Donders Institute for Brain, Cognition and Behaviour: Centre for Cognition, Radboud University, Montessorilaan 3, 6525 HE, Nijmegen, The Netherlands. r.vlek@donders.ru.nl
authors.forename: R J
authors.initials: RJ
authors.lastname: Vlek
authors.forename: R S
authors.initials: RS
authors.lastname: Schaefer
authors.forename: C C A M
authors.initials: CC
authors.lastname: Gielen
authors.forename: J D R
authors.initials: JD
authors.lastname: Farquhar
authors.forename: P
authors.initials: P
authors.lastname: Desain
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods*; D000328:Adult; D001307:Auditory Perception / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D004569:Electroencephalography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D009146:Music; D046709:Pattern Recognition, Physiological / Q000502:physiology*; D014584:User-Computer Interface; D055815:Young Adult