title: Brain-computer interface design for asynchronous control applications: improvements to the LF-ASD asynchronous brain switch.
abstract: The low-frequency asynchronous switch design (LF-ASD) was introduced as a direct brain-computer interface (BCI) technology for asynchronous control applications. The LF-ASD operates as an asynchronous brain switch (ABS) which is activated only when a user intends control and maintains an inactive state output when the user is not meaning to control the device (i.e., they may be idle, thinking about a problem, or performing some other action). Results from LF-ASD evaluations have shown promise, although the reported error rates are too high for most practical applications. This paper presents the evaluation of four new LF-ASD designs with data collected from individuals with high-level spinal cord injuries and able-bodied subjects. These new designs incorporated electroencephalographic energy normalization and feature space dimensionality reduction. The error characteristics of the new ABS designs were significantly better than the LF-ASD design with true positive rate increases of approximately 33% for false positive rates in the range of 1%-2%. The results demonstrate that the dimensionality of the LF-ASD feature space can be reduced without performance degradation. The results also confirm previous findings that spinal cord-injured subjects can operate ABS designs to the same ability as able-bodied subjects.
authors.affiliation: Neil Squire Foundation, Burnaby, BC V5M 3Z3, Canada. jaimieb@neilsquire.ca
authors.forename: Jaimie F
authors.initials: JF
authors.lastname: Borisoff
authors.forename: Steve G
authors.initials: SG
authors.lastname: Mason
authors.forename: Ali
authors.initials: A
authors.lastname: Bashashati
authors.forename: Gary E
authors.initials: GE
authors.lastname: Birch
mesh_terms: D000328:Adult; D000465:Algorithms; D001921:Brain / Q000502:physiology; D003143:Communication Devices for People with Disabilities; D004569:Electroencephalography / Q000379:methods*; D005071:Evoked Potentials / Q000502:physiology*; D005246:Feedback / Q000502:physiology; D005260:Female; D006801:Humans; D016247:Information Storage and Retrieval / Q000379:methods; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000502:physiology*; D009862:Online Systems; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014584:User-Computer Interface