title: Automatic determination of EMG-contaminated components and validation of independent component analysis using EEG during pharmacologic paralysis.
abstract: OBJECTIVE
  Validate independent component analysis (ICA) for removal of EMG contamination from EEG, and demonstrate a heuristic, based on the gradient of EEG spectra (slope of graph of log EEG power vs log frequency, 7-70 Hz) from paralysed awake humans, to automatically identify and remove components that are predominantly EMG.
  
  
  METHODS
  We studied the gradient of EMG-free EEG spectra to quantitatively inform the choice of threshold. Then, pre-existing EEG from 3 disparate experimental groups was examined before and after applying the heuristic to validate that the heuristic preserved neurogenic activity (Berger effect, auditory odd ball, visual and auditory steady state responses).
  
  
  RESULTS
  (1) ICA-based EMG removal diminished EMG contamination up to approximately 50 Hz, (2) residual EMG contamination using automatic selection was similar to manual selection, and (3) task-induced cortical activity remained, was enhanced, or was revealed using the ICA-based methodology.
  
  
  CONCLUSIONS
  This study further validates ICA as a powerful technique for separating and removing myogenic signals from EEG. Automatic processing based on spectral gradients to exclude EMG-containing components is a conceptually simple and valid technique.
  
  
  CONCLUSIONS
  This study strengthens ICA as a technique to remove EMG contamination from EEG whilst preserving neurogenic activity to 50 Hz.
authors.affiliation: School of Medicine, Flinders University, Adelaide, Australia; Oxford Centre for FMRI of the Brain, Nuffield Department of Clinical Neurosciences, University of Oxford, UK.
authors.forename: S P
authors.initials: SP
authors.lastname: Fitzgibbon
authors.affiliation: School of Computer Science, Engineering and Mathematics, Flinders University, Adelaide, Australia.
authors.forename: D
authors.initials: D
authors.lastname: DeLosAngeles
authors.affiliation: School of Computer Science, Engineering and Mathematics, Flinders University, Adelaide, Australia; Medical Device Research Institute, Flinders University, Adelaide, Australia.
authors.forename: T W
authors.initials: TW
authors.lastname: Lewis
authors.affiliation: School of Computer Science, Engineering and Mathematics, Flinders University, Adelaide, Australia; Medical Device Research Institute, Flinders University, Adelaide, Australia; College of Computer Science & Technology, Beijing University of Technology, Beijing, PR China.
authors.forename: D M W
authors.initials: DM
authors.lastname: Powers
authors.affiliation: School of Computer Science, Engineering and Mathematics, Flinders University, Adelaide, Australia; Centre for Neuroscience, Flinders University, Adelaide, Australia; Medical Device Research Institute, Flinders University, Adelaide, Australia.
authors.forename: T S
authors.initials: TS
authors.lastname: Grummett
authors.affiliation: School of Medicine, Flinders University, Adelaide, Australia.
authors.forename: E M
authors.initials: EM
authors.lastname: Whitham
authors.affiliation: Department of Psychology and Brain Research Centre, University of British Columbia, Vancouver, Canada.
authors.forename: L M
authors.initials: LM
authors.lastname: Ward
authors.affiliation: School of Medicine, Flinders University, Adelaide, Australia; Centre for Neuroscience, Flinders University, Adelaide, Australia. Electronic address: John.willoughby@flinders.edu.au.
authors.forename: J O
authors.initials: JO
authors.lastname: Willoughby
authors.affiliation: School of Computer Science, Engineering and Mathematics, Flinders University, Adelaide, Australia; Medical Device Research Institute, Flinders University, Adelaide, Australia.
authors.forename: K J
authors.initials: KJ
authors.lastname: Pope
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D004569:Electroencephalography / Q000379:methods*; D004576:Electromyography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010243:Paralysis / Q000175:diagnosis / Q000503:physiopathology*; D010775:Photic Stimulation / Q000379:methods; D025341:Principal Component Analysis / Q000379:methods*; D055815:Young Adult
keywords: Alpha rhythms; Electroencephalogram; Electromyogram; Neuromuscular paralysis; Oddball; Photic stimulation; Steady state responses