Operant H-reflex Down-conditioning of Rectus Femoris in Post-stroke Stiff Knee Gait

Operant H-reflex Down-conditioning of Rectus Femoris in Post-stroke Stiff Knee Gait

The investigators performed a feasibility trial of operant conditioning of spinal reflex excitability on five healthy individuals and two post-stroke individuals. The investigators found that operant conditioning of rectus femoris reflex excitability was feasible in all participants.

The investigators 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). The investigators' main outcome measure was rectus femoris H-reflex magnitude. We also examined H-reflex magnitude of other quadriceps muscles.

Inclusion Criteria:

• Premorbidly independent
• Mild to moderate impairment determined by standard practices per the physical therapist
• Ability to stand for 10-minute intervals unassisted
• Ability to walk for 10-minutes on a treadmill
• Reduced knee flexion during phase and SKG as determined by a clinician
• Hemiparesis
• Ability to provide informed consent

Exclusion Criteria:

• History of cerebellar stroke, multiple stroke
• History of serious lower limb musculoskeletal injury
• Functionally relevant osteoarthritis and weight-bearing restrictions
• Have condition related to claustrophobia or other MRI contraindications
• Functionally relevant cognitive impairment
• Functionally relevant vision impairment
• Took antispasmodic medication one day prior to the session
• Had Botox injection one week prior to the session
• Pregnant women