Project Grant R21HD112862

NEUROMUSCULAR ELECTRICAL STIMULATION TO FACILITATE PERTURBATION-BASED REACTIVE BALANCE TRAINING FOR FALL-RISK REDUCTION POST-STROKE: THE REACTPLUSNMES TRIAL - THIS STUDY AIMS TO IMPROVE FALL PREVENTION INTERVENTIONS IN MODERATE TO SEVERELY IMPAIRED PEOPLE WITH CHRONIC HEMIPARETIC STROKE (PWCHS) BY PROVIDING SYNCHRONOUS NEUROMUSCULAR ELECTRICAL STIMULATION (NMES) AND PERTURBATION-BASED REACTIVE BALANCE TRAINING (REACT). REACT IS AN EMERGING INTERVENTION CONSISTING OF REPEATED SUPPORT SURFACE DISTURBANCES IN A SAFE AND CONTROLLED ENVIRONMENT TO IMPROVE REACTIVE RESPONSES. FALLS POSE A SIGNIFICANT PHYSICAL, PSYCHOLOGICAL, AND ECONOMIC BURDEN, WITH COMMUNITY DWELLING PWCHS FALLING ABOUT THREE-TIMES MORE THAN THEIR HEALTHY COUNTERPARTS. OUR PREVIOUS RESEARCH SHOWS THAT PWCHS HAVE BIOMECHANICAL IMPAIRMENTS IN REACTIVE BALANCE, INCLUDING FAILURE OF PARETIC LIMB TO PROVIDE ADEQUATE LIMB SUPPORT DURING REACTIVE STEPPING WITH THE PREFERRED NON-PARETIC LIMB, ESPECIALLY AT HIGH INTENSITY PERTURBATIONS. CURRENT FALL PREVENTION INTERVENTIONS, INCLUDING CONVENTIONAL EXERCISE AND BALANCE TRAINING, ARE LIMITED IN THEIR ABILITY TO ENHANCE REACTIVE BALANCE (PROTECTIVE RESPONSES FOLLOWING BALANCE LOSS) IN PWCHS. WE ALSO SHOWED THAT PWCHS HAD SLOWER ADAPTATION WHEN EXPOSED TO LARGE MAGNITUDE SLIPS ON THE PARETIC SIDE. FURTHER, WE DEMONSTRATED THAT PWCHS WITH HIGHER MOTOR IMPAIRMENT SHOWED LESS IMPROVEMENT AFTER TREADMILL STANCE REACT. HENCE, THERE IS AN URGENT NEED TO ESTABLISH INTERVENTIONS THAT FOCUS ON ENHANCING REACTIVE BALANCE ON PARETIC LIMB IN PWCHS (ESPECIALLY HIGHLY IMPAIRED). NMES IS AN INTERVENTION KNOWN TO FACILITATE PARETIC LIMB PERFORMANCE AND MOTOR LEARNING; HOWEVER, THE USE OF NMES AS A FACILITATORY AGENT TO ENHANCE REACTIVE BALANCE IMPROVEMENTS (STABILITY AND LIMB SUPPORT DURING STEPPING RESPONSES) FOR FALL PREVENTION HAS NEVER BEEN TESTED. OUR PUBLISHED STUDY SHOWED THAT PEOPLE GIVEN NMES (TO PARETIC QUADRICEPS) DURING TREADMILL STANCE SLIPS HAD IN LOWER FALLS THAN THOSE WITHOUT NMES. FURTHER, NMES AND REACT INTERVENTIONS BOTH TRANSLATE TO IMPROVEMENTS IN CLINICAL MEASURES OF BALANCE (MINI-BESTEST), MOBILITY (10M WALK TEST), AND FALLS EFFICACY (ACTIVITIES SPECIFIC BALANCE CONFIDENCE, ABC). THUS, THIS NOVEL STUDY AIMS TO EXAMINE THERAPEUTIC EFFECTS OF NMES PROVIDED TO QUADRICEPS MUSCLE OF THE PARETIC LIMB TO IMPROVE BIOMECHANICAL AND CLINICAL OUTCOMES IN MODERATE TO SEVERELY IMPAIRED PWCHS DURING SIX WEEKS (12 SESSIONS) OF REACT (REACT+NMES). EMERGING EVIDENCE INDICATES THAT REACT AND NMES INDEPENDENTLY CAN RESULT IN CHANGES IN CORTICAL POTENTIALS AND CORTICOSPINAL EXCITABILITY WITH CORRESPONDING CHANGES IN LEG MUSCLE ACTIVATIONS. HOWEVER, THESE EFFECTS HAVE NOT BEEN EXAMINED PWCHS, ESPECIALLY WITH HIGH IMPAIRMENT. THEREFORE, WE ALSO AIM TO EXAMINE NEUROMUSCULAR AND NEUROPLASTIC EFFECTS OF REACT+NMES, WHICH WOULD FURTHER THE UNDERSTANDING OF LONG-TERM IMPROVEMENTS IN FALL-RESISTING SKILLS AND IMPROVE CLINICAL TRANSLATION OF REACT+NMES. THE FINDINGS OF THIS STUDY WILL PROVIDE EVIDENCE FOR FEASIBILITY OF CLINICAL TRANSLATION OF REACT+NMES AS A TECHNIQUE TO LOWER FALL-RISK IN PWCHS. THIS STUDY WILL AID THE DEVELOPMENT OF EFFECTIVE FALL PREVENTION INTERVENTIONS THAT POTENTIALLY FACILITATE REACTIVE BALANCE IMPROVEMENTS, REDUCE TRAINING TIMES, AND INCLUDE PERSONS WITH HIGH IMPAIRMENT.