We performed a cohort study on 7 individuals (5 healthy, 2 post-stroke) to examine the feasibility of operant down-conditioning of rectus femoris reflex excitability (i.e. H-reflex). Each individual performed 30 sessions, 6 baseline sessions with no operant conditioning (225 trials of surface electrical stimulation of the femoral nerve), followed by 24 training sessions (20 baseline trials followed by 225 trials with feedback of H-reflex magnitude). Our main outcome measure was rectus femoris H-reflex magnitude. We also examined H-reflex magnitude of other quadriceps muscles.
We performed a feasibility trial of operant conditioning of spinal reflex excitability on five healthy individuals and two post-stroke individuals. We found that operant conditioning of rectus femoris reflex excitability was feasible in all participants.