title: Brain-Computer Interface-Based Communication in the Completely Locked-In State.
abstract: Despite partial success, communication has remained impossible for persons suffering from complete motor paralysis but intact cognitive and emotional processing, a state called complete locked-in state (CLIS). Based on a motor learning theoretical context and on the failure of neuroelectric brain-computer interface (BCI) communication attempts in CLIS, we here report BCI communication using functional near-infrared spectroscopy (fNIRS) and an implicit attentional processing procedure. Four patients suffering from advanced amyotrophic lateral sclerosis (ALS)-two of them in permanent CLIS and two entering the CLIS without reliable means of communication-learned to answer personal questions with known answers and open questions all requiring a "yes" or "no" thought using frontocentral oxygenation changes measured with fNIRS. Three patients completed more than 46 sessions spread over several weeks, and one patient (patient W) completed 20 sessions. Online fNIRS classification of personal questions with known answers and open questions using linear support vector machine (SVM) resulted in an above-chance-level correct response rate over 70%. Electroencephalographic oscillations and electrooculographic signals did not exceed the chance-level threshold for correct communication despite occasional differences between the physiological signals representing a "yes" or "no" response. However, electroencephalogram (EEG) changes in the theta-frequency band correlated with inferior communication performance, probably because of decreased vigilance and attention. If replicated with ALS patients in CLIS, these positive results could indicate the first step towards abolition of complete locked-in states, at least for ALS.
authors.affiliation: Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany.
authors.forename: Ujwal
authors.initials: U
authors.lastname: Chaudhary
authors.affiliation: Shanghai Maritime University, Shanghai, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Xia
authors.affiliation: Department of Cognitive and Clinical Neuroscience, Central Institute of Mental Health, Mannheim, Germany.
authors.forename: Stefano
authors.initials: S
authors.lastname: Silvoni
authors.affiliation: Human Cortical Physiology and Stroke Neurorehabilitation Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Leonardo G
authors.initials: LG
authors.lastname: Cohen
authors.affiliation: Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany.|Ospedale San Camillo, IRCCS, Venice, Italy.|Wyss Center for Bio and Neuroengineering, Geneva, Switzerland.
authors.forename: Niels
authors.initials: N
authors.lastname: Birbaumer
mesh_terms: D062207:Brain-Computer Interfaces; D003142:Communication; D004569:Electroencephalography; D006801:Humans; D010108:Oxyhemoglobins / Q000378:metabolism; D011782:Quadriplegia / Q000503:physiopathology*; D012372:ROC Curve; D012815:Signal Processing, Computer-Assisted; D019265:Spectroscopy, Near-Infrared
chemical_list: D010108:Oxyhemoglobins