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.

Grant Number: 1R21HD112862-01
NIH Institute/Center: NIH
Principal Investigator: Tanvi Bhatt