title: P300-based brain-computer interface (BCI) event-related potentials (ERPs): People with amyotrophic lateral sclerosis (ALS) vs. age-matched controls.
abstract: OBJECTIVE
  Brain-computer interfaces (BCIs) aimed at restoring communication to people with severe neuromuscular disabilities often use event-related potentials (ERPs) in scalp-recorded EEG activity. Up to the present, most research and development in this area has been done in the laboratory with young healthy control subjects. In order to facilitate the development of BCI most useful to people with disabilities, the present study set out to: (1) determine whether people with amyotrophic lateral sclerosis (ALS) and healthy, age-matched volunteers (HVs) differ in the speed and accuracy of their ERP-based BCI use; (2) compare the ERP characteristics of these two groups; and (3) identify ERP-related factors that might enable improvement in BCI performance for people with disabilities.
  
  
  METHODS
  Sixteen EEG channels were recorded while people with ALS or healthy age-matched volunteers (HVs) used a P300-based BCI. The subjects with ALS had little or no remaining useful motor control (mean ALS Functional Rating Scale-Revised 9.4 (±9.5SD) (range 0-25)). Each subject attended to a target item as the items in a 6×6 visual matrix flashed. The BCI used a stepwise linear discriminant function (SWLDA) to determine the item the user wished to select (i.e., the target item). Offline analyses assessed the latencies, amplitudes, and locations of ERPs to the target and non-target items for people with ALS and age-matched control subjects.
  
  
  RESULTS
  BCI accuracy and communication rate did not differ significantly between ALS users and HVs. Although ERP morphology was similar for the two groups, their target ERPs differed significantly in the location and amplitude of the late positivity (P300), the amplitude of the early negativity (N200), and the latency of the late negativity (LN).
  
  
  CONCLUSIONS
  The differences in target ERP components between people with ALS and age-matched HVs are consistent with the growing recognition that ALS may affect cortical function. The development of BCIs for use by this population may begin with studies in HVs but also needs to include studies in people with ALS. Their differences in ERP components may affect the selection of electrode montages, and might also affect the selection of presentation parameters (e.g., matrix design, stimulation rate).
  
  
  CONCLUSIONS
  P300-based BCI performance in people severely disabled by ALS is similar to that of age-matched control subjects. At the same time, their ERP components differ to some degree from those of controls. Attention to these differences could contribute to the development of BCIs useful to those with ALS and possibly to others with severe neuromuscular disabilities.
authors.affiliation: Laboratory of Neural Injury and Repair, Wadsworth Center, New York State Department of Health, Albany, NY, USA; Helen Hayes Rehabilitation Hospital, New York State Department of Health, West Haverstraw, NY, USA. Electronic address: Lynn.McCane@health.ny.gov.
authors.forename: Lynn M
authors.initials: LM
authors.lastname: McCane
authors.affiliation: Laboratory of Neural Injury and Repair, Wadsworth Center, New York State Department of Health, Albany, NY, USA; Helen Hayes Rehabilitation Hospital, New York State Department of Health, West Haverstraw, NY, USA.
authors.forename: Susan M
authors.initials: SM
authors.lastname: Heckman
authors.affiliation: Laboratory of Neural Injury and Repair, Wadsworth Center, New York State Department of Health, Albany, NY, USA; Helen Hayes Rehabilitation Hospital, New York State Department of Health, West Haverstraw, NY, USA.
authors.forename: Dennis J
authors.initials: DJ
authors.lastname: McFarland
authors.affiliation: Laboratory of Neural Injury and Repair, Wadsworth Center, New York State Department of Health, Albany, NY, USA; Helen Hayes Rehabilitation Hospital, New York State Department of Health, West Haverstraw, NY, USA.
authors.forename: George
authors.initials: G
authors.lastname: Townsend
authors.affiliation: Laboratory of Neural Injury and Repair, Wadsworth Center, New York State Department of Health, Albany, NY, USA; Helen Hayes Rehabilitation Hospital, New York State Department of Health, West Haverstraw, NY, USA.
authors.forename: Joseph N
authors.initials: JN
authors.lastname: Mak
authors.affiliation: Laboratory of Neural Injury and Repair, Wadsworth Center, New York State Department of Health, Albany, NY, USA; Helen Hayes Rehabilitation Hospital, New York State Department of Health, West Haverstraw, NY, USA.
authors.forename: Eric W
authors.initials: EW
authors.lastname: Sellers
authors.affiliation: Laboratory of Neural Injury and Repair, Wadsworth Center, New York State Department of Health, Albany, NY, USA; Helen Hayes Rehabilitation Hospital, New York State Department of Health, West Haverstraw, NY, USA.
authors.forename: Debra
authors.initials: D
authors.lastname: Zeitlin
authors.affiliation: Laboratory of Neural Injury and Repair, Wadsworth Center, New York State Department of Health, Albany, NY, USA; Helen Hayes Rehabilitation Hospital, New York State Department of Health, West Haverstraw, NY, USA.
authors.forename: Laura M
authors.initials: LM
authors.lastname: Tenteromano
authors.affiliation: Laboratory of Neural Injury and Repair, Wadsworth Center, New York State Department of Health, Albany, NY, USA; Helen Hayes Rehabilitation Hospital, New York State Department of Health, West Haverstraw, NY, USA.
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Wolpaw
authors.affiliation: Laboratory of Neural Injury and Repair, Wadsworth Center, New York State Department of Health, Albany, NY, USA; Helen Hayes Rehabilitation Hospital, New York State Department of Health, West Haverstraw, NY, USA.
authors.forename: Theresa M
authors.initials: TM
authors.lastname: Vaughan
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D000690:Amyotrophic Lateral Sclerosis / Q000503:physiopathology*; D001931:Brain Mapping; D062207:Brain-Computer Interfaces; D016022:Case-Control Studies; D003142:Communication; D004569:Electroencephalography; D018913:Event-Related Potentials, P300 / Q000502:physiology*; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011930:Reaction Time / Q000502:physiology; D014785:Vision, Ocular / Q000502:physiology
keywords: Alternative and augmentative communication (AAC); Amyotrophic lateral sclerosis (ALS); Brain-computer interface (BCI); Brain-machine interface (BMI); Electroencephalography (EEG); Event-related potentials (ERP)