title: Neural decoding of treadmill walking from noninvasive electroencephalographic signals.
abstract: Chronic recordings from ensembles of cortical neurons in primary motor and somatosensory areas in rhesus macaques provide accurate information about bipedal locomotion (Fitzsimmons NA, Lebedev MA, Peikon ID, Nicolelis MA. Front Integr Neurosci 3: 3, 2009). Here we show that the linear and angular kinematics of the ankle, knee, and hip joints during both normal and precision (attentive) human treadmill walking can be inferred from noninvasive scalp electroencephalography (EEG) with decoding accuracies comparable to those from neural decoders based on multiple single-unit activities (SUAs) recorded in nonhuman primates. Six healthy adults were recorded. Participants were asked to walk on a treadmill at their self-selected comfortable speed while receiving visual feedback of their lower limbs (i.e., precision walking), to repeatedly avoid stepping on a strip drawn on the treadmill belt. Angular and linear kinematics of the left and right hip, knee, and ankle joints and EEG were recorded, and neural decoders were designed and optimized with cross-validation procedures. Of note, the optimal set of electrodes of these decoders were also used to accurately infer gait trajectories in a normal walking task that did not require subjects to control and monitor their foot placement. Our results indicate a high involvement of a fronto-posterior cortical network in the control of both precision and normal walking and suggest that EEG signals can be used to study in real time the cortical dynamics of walking and to develop brain-machine interfaces aimed at restoring human gait function.
authors.affiliation: Neural Engineering and Smart Prosthetics Research Laboratory, Department of Kinesiology, School of Public Health, University of Maryland, College Park, MD 20742, USA.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Presacco
authors.forename: Ronald
authors.initials: R
authors.lastname: Goodman
authors.forename: Larry
authors.initials: L
authors.lastname: Forrester
authors.forename: Jose Luis
authors.initials: JL
authors.lastname: Contreras-Vidal
mesh_terms: D000293:Adolescent; D000328:Adult; D000843:Ankle Joint / Q000502:physiology; D016477:Artifacts; D001696:Biomechanical Phenomena; D001931:Brain Mapping; D003199:Computer Systems; D004569:Electroencephalography / Q000379:methods; D005133:Eye Movements / Q000502:physiology; D056228:Feedback, Sensory; D005260:Female; D005684:Gait; D006621:Hip Joint / Q000502:physiology; D006801:Humans; D007719:Knee Joint / Q000502:physiology; D007866:Leg / Q000502:physiology*; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D012535:Scalp; D012815:Signal Processing, Computer-Assisted; D013003:Somatosensory Cortex / Q000502:physiology*; D014584:User-Computer Interface; D016138:Walking / Q000502:physiology*; D055815:Young Adult