title: EEG correlates of P300-based brain-computer interface (BCI) performance in people with amyotrophic lateral sclerosis.
abstract: The purpose of this study was to identify electroencephalography (EEG) features that correlate with P300-based brain-computer interface (P300 BCI) performance in people with amyotrophic lateral sclerosis (ALS). Twenty people with ALS used a P300 BCI spelling application in copy-spelling mode. Three types of EEG features were found to be good predictors of P300 BCI performance: (1) the root-mean-square amplitude and (2) the negative peak amplitude of the event-related potential to target stimuli (target ERP) at Fz, Cz, P3, Pz, and P4; and (3) EEG theta frequency (4.5-8 Hz) power at Fz, Cz, P3, Pz, P4, PO7, PO8 and Oz. A statistical prediction model that used a subset of these features accounted for >60% of the variance in copy-spelling performance (p < 0.001, mean R(2) = 0.6175). The correlations reflected between-subject, rather than within-subject, effects. The results enhance understanding of performance differences among P300 BCI users. The predictors found in this study might help in: (1) identifying suitable candidates for long-term P300 BCI operation; (2) assessing performance online. Further work on within-subject effects needs to be done to establish whether P300 BCI user performance could be improved by optimizing one or more of these EEG features.
authors.affiliation: NeuroSky (Hong Kong) Co. Ltd, Hong Kong, People's Republic of China. josephnfmak@gmail.com
authors.forename: Joseph N
authors.initials: JN
authors.lastname: Mak
authors.forename: Dennis J
authors.initials: DJ
authors.lastname: McFarland
authors.forename: Theresa M
authors.initials: TM
authors.lastname: Vaughan
authors.forename: Lynn M
authors.initials: LM
authors.lastname: McCane
authors.forename: Phillippa Z
authors.initials: PZ
authors.lastname: Tsui
authors.forename: Debra J
authors.initials: DJ
authors.lastname: Zeitlin
authors.forename: Eric W
authors.initials: EW
authors.lastname: Sellers
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Wolpaw
mesh_terms: D000368:Aged; D000465:Algorithms; D000690:Amyotrophic Lateral Sclerosis / Q000523:psychology*; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D003627:Data Interpretation, Statistical; D006233:Persons with Disabilities; D016002:Discriminant Analysis; D004569:Electroencephalography; D018913:Event-Related Potentials, P300 / Q000502:physiology*; D005260:Female; D005544:Forecasting; D006801:Humans; D016018:Least-Squares Analysis; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009862:Online Systems; D010775:Photic Stimulation; D015203:Reproducibility of Results; D012984:Software; D013826:Theta Rhythm / Q000502:physiology; D014584:User-Computer Interface