title: Brain-computer interface (BCI) evaluation in people with amyotrophic lateral sclerosis.
abstract: Brain-computer interfaces (BCIs) might restore communication to people severely disabled by amyotrophic lateral sclerosis (ALS) or other disorders. We sought to: 1) define a protocol for determining whether a person with ALS can use a visual P300-based BCI; 2) determine what proportion of this population can use the BCI; and 3) identify factors affecting BCI performance. Twenty-five individuals with ALS completed an evaluation protocol using a standard 6 × 6 matrix and parameters selected by stepwise linear discrimination. With an 8-channel EEG montage, the subjects fell into two groups in BCI accuracy (chance accuracy 3%). Seventeen averaged 92 (± 3)% (range 71-100%), which is adequate for communication (G70 group). Eight averaged 12 (± 6)% (range 0-36%), inadequate for communication (L40 subject group). Performance did not correlate with disability: 11/17 (65%) of G70 subjects were severely disabled (i.e. ALSFRS-R < 5). All L40 subjects had visual impairments (e.g. nystagmus, diplopia, ptosis). P300 was larger and more anterior in G70 subjects. A 16-channel montage did not significantly improve accuracy. In conclusion, most people severely disabled by ALS could use a visual P300-based BCI for communication. In those who could not, visual impairment was the principal obstacle. For these individuals, auditory P300-based BCIs might be effective.
authors.affiliation: Laboratory of Neural Injury and Repair, Wadsworth Center, New York State Department of Health , Albany , New York , and Helen Hayes Rehabilitation Hospital, New York State Department of Health , West Haverstraw, New York , USA.
authors.forename: Lynn M
authors.initials: LM
authors.lastname: McCane
authors.forename: Eric W
authors.initials: EW
authors.lastname: Sellers
authors.forename: Dennis J
authors.initials: DJ
authors.lastname: McFarland
authors.forename: Joseph N
authors.initials: JN
authors.lastname: Mak
authors.forename: C Steve
authors.initials: CS
authors.lastname: Carmack
authors.forename: Debra
authors.initials: D
authors.lastname: Zeitlin
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Wolpaw
authors.forename: Theresa M
authors.initials: TM
authors.lastname: Vaughan
mesh_terms: D000328:Adult; D000368:Aged; D000690:Amyotrophic Lateral Sclerosis / Q000150:complications* / Q000175:diagnosis*; D001676:Biofeedback, Psychology; D062207:Brain-Computer Interfaces; D003147:Communication Disorders / Q000209:etiology* / Q000534:rehabilitation*; D004569:Electroencephalography; D018913:Event-Related Potentials, P300 / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009862:Online Systems; D010775:Photic Stimulation; D011597:Psychomotor Performance / Q000502:physiology; D011930:Reaction Time / Q000502:physiology
keywords: Amyotrophic lateral sclerosis (ALS); P300; augmentative and alternative communication (AAC); brain-computer interface (BCI); event-related potentials (ERP); rehabilitation