title: Coarse electrocorticographic decoding of ipsilateral reach in patients with brain lesions.
abstract: In patients with unilateral upper limb paralysis from strokes and other brain lesions, strategies for functional recovery may eventually include brain-machine interfaces (BMIs) using control signals from residual sensorimotor systems in the damaged hemisphere. When voluntary movements of the contralateral limb are not possible due to brain pathology, initial training of such a BMI may require use of the unaffected ipsilateral limb. We conducted an offline investigation of the feasibility of decoding ipsilateral upper limb movements from electrocorticographic (ECoG) recordings in three patients with different lesions of sensorimotor systems associated with upper limb control. We found that the first principal component (PC) of unconstrained, naturalistic reaching movements of the upper limb could be decoded from ipsilateral ECoG using a linear model. ECoG signal features yielding the best decoding accuracy were different across subjects. Performance saturated with very few input features. Decoding performances of 0.77, 0.73, and 0.66 (median Pearson's r between the predicted and actual first PC of movement using nine signal features) were achieved in the three subjects. The performance achieved here with small numbers of electrodes and computationally simple decoding algorithms suggests that it may be possible to control a BMI using ECoG recorded from damaged sensorimotor brain systems.
authors.affiliation: Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States of America.
authors.forename: Guy
authors.initials: G
authors.lastname: Hotson
authors.affiliation: Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21205, United States of America.
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Fifer
authors.affiliation: Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21205, United States of America.
authors.forename: Soumyadipta
authors.initials: S
authors.lastname: Acharya
authors.affiliation: Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21205, United States of America.
authors.forename: Heather L
authors.initials: HL
authors.lastname: Benz
authors.affiliation: Department of Neurosurgery, Johns Hopkins University, Baltimore, Maryland 21287, United States of America.
authors.forename: William S
authors.initials: WS
authors.lastname: Anderson
authors.affiliation: Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21205, United States of America.
authors.forename: Nitish V
authors.initials: NV
authors.lastname: Thakor
authors.affiliation: Department of Neurology, Johns Hopkins University, Baltimore, Maryland 21287, United States of America.
authors.forename: Nathan E
authors.initials: NE
authors.lastname: Crone
mesh_terms: D000328:Adult; D001132:Arm / Q000294:innervation / Q000503:physiopathology; D062207:Brain-Computer Interfaces; D005260:Female; D006801:Humans; D008297:Male; D009044:Motor Cortex / Q000503:physiopathology; D009068:Movement; D010243:Paralysis / Q000503:physiopathology*; D013003:Somatosensory Cortex / Q000503:physiopathology; D020521:Stroke / Q000503:physiopathology*