Brain-controlled functional electrical stimulation therapy for gait rehabilitation after stroke: A safety study

Background: many stroke survivors have significant long-term gait impairment,often involving foot drop. current physiotherapies provide limited recovery. orthoses substitute for ankle strength,but they provide no lasting therapeutic effect. brain-computer interface (bci)-controlled functional electrical stimulation (fes) is a novel rehabilitative approach that may generate permanent neurological improvements. this study explores the safety and feasibility of a foot-drop-targeted bci-fes physiotherapy in chronic stroke survivors. methods: subjects (n=9) operated an electroencephalogram-based bci-fes system for foot dorsiflexion in 12 one-hour sessions over four weeks. gait speed,dorsiflexion active range of motion (arom),six-minute walk distance (6mwd),and fugl-meyer leg motor (fm-lm) scores were assessed before,during,and after therapy. the primary safety outcome measure was the proportion of subjects that deteriorated in gait speed by ≥0.16 m/s at one week or four weeks post-therapy. the secondary outcome measures were the proportion of subjects that experienced a clinically relevant decrease in dorsiflexion arom (≥2.5˚),6mwd (≥20 %),and fm-lm score (≥10 %) at either post-therapy assessment. results: no subjects (0/9) experienced a clinically significant deterioration in gait speed,dorsiflexion arom,6mwt distance,or fm-lm score at either post-therapy assessment. five subjects demonstrated a detectable increase (≥0.06 m/s) in gait speed,three subjects demonstrated a detectable increase (≥2.5) in dorsiflexion arom,five subjects demonstrated a detectable increase (≥10 %) in 6mwd,and three subjects demonstrated a detectable increase (≥10 %) in fm-lm. five of the six subjects that exhibited a detectable increase in either post-therapy gait speed or 6mwd also exhibited significant (p<0.01 using a mann-whitney u test) increases in electroencephalogram event-related synchronization/desynchronization. additionally,two subjects experienced a clinically important increase (≥0.16 m/s) in gait speed,and four subjects experienced a clinically important increase (≥20 %) in 6mwd. linear mixed models of gait speed,dorsiflexion arom,6mwd,and fm-lm scores suggest that bci-fes therapy is associated with an increase in lower motor performance at a statistically,yet not clinically,significant level. conclusion: bci-fes therapy is safe. if it is shown to improve post-stroke gait function in future studies,it could provide a new gait rehabilitation option for severely impaired patients. formal clinical trials are warranted. © 2015 mccrimmon et al.