title: An automated and fast approach to detect single-trial visual evoked potentials with application to brain-computer interface.
abstract: OBJECTIVE
  This study aims (1) to develop an automated and fast approach for detecting visual evoked potentials (VEPs) in single trials and (2) to apply the single-trial VEP detection approach in designing a real-time and high-performance brain-computer interface (BCI) system.
  
  
  METHODS
  The single-trial VEP detection approach uses common spatial pattern (CSP) as a spatial filter and wavelet filtering (WF) a temporal-spectral filter to jointly enhance the signal-to-noise ratio (SNR) of single-trial VEPs. The performance of the joint spatial-temporal-spectral filtering approach was assessed in a four-command VEP-based BCI system.
  
  
  RESULTS
  The offline classification accuracy of the BCI system was significantly improved from 67.6±12.5% (raw data) to 97.3±2.1% (data filtered by CSP and WF). The proposed approach was successfully implemented in an online BCI system, where subjects could make 20 decisions in one minute with classification accuracy of 90%.
  
  
  CONCLUSIONS
  The proposed single-trial detection approach is able to obtain robust and reliable VEP waveform in an automatic and fast way and it is applicable in VEP based online BCI systems.
  
  
  CONCLUSIONS
  This approach provides a real-time and automated solution for single-trial detection of evoked potentials or event-related potentials (EPs/ERPs) in various paradigms, which could benefit many applications such as BCI and intraoperative monitoring.
authors.affiliation: Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong, China.
authors.forename: Yiheng
authors.initials: Y
authors.lastname: Tu
authors.affiliation: Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong, China.
authors.forename: Yeung Sam
authors.initials: YS
authors.lastname: Hung
authors.affiliation: Key Laboratory of Cognition and Personality (Ministry of Education), School of Psychology, Southwest University, Chongqing, China.
authors.forename: Li
authors.initials: L
authors.lastname: Hu
authors.affiliation: Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong, China.
authors.forename: Gan
authors.initials: G
authors.lastname: Huang
authors.affiliation: Department of Orthopaedics and Traumatology, The University of Hong Kong, Pokfulam Road, Hong Kong, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong, China. Electronic address: zgzhang@eee.hku.hk.
authors.forename: Zhiguo
authors.initials: Z
authors.lastname: Zhang
mesh_terms: D000328:Adult; D057205:Automation, Laboratory / Q000379:methods; D001921:Brain / Q000502:physiology*; D062207:Brain-Computer Interfaces; D004569:Electroencephalography / Q000379:methods; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D010775:Photic Stimulation / Q000379:methods; D059629:Signal-To-Noise Ratio; D013997:Time Factors; D055815:Young Adult
keywords: Brain–computer interface; Common spatial filtering; Single-trial detection; Visual evoked potentials; Wavelet analysis