TY - JOUR
T1 - Investigating the underlying biomechanical mechanisms leading to falls in long-term ankle-foot orthosis and functional electrical stimulator users with chronic stroke
AU - Nevisipour, Masood
AU - Honeycutt, Claire F.
N1 - Publisher Copyright:
© 2021 Elsevier B.V.
PY - 2022/2
Y1 - 2022/2
N2 - Background: Ankle-foot-orthoses (AFOs) and functional electrical stimulators (FES) are commonly prescribed to treat foot-drop in individuals with stroke. Despite well-established positive impacts of AFO and FES devices on balance and gait, AFO and FES-users still fall at a high rate. Objective: The objective of this study was to investigate 1) the underlying biomechanical mechanisms leading to a fall in long-term AFO and FES-users with chronic stroke and 2) the impacts of AFOs and FES devices on fall outcomes and compensatory stepping response of long-term users with chronic stroke. Methods: Fall outcomes as well as kinematics and kinetics of compensatory stepping response of 42 individuals with chronic stroke (14 AFO-users, 10 FES-users, 18 Non-users) were evaluated during trip-like treadmill perturbations. AFO and FES-users were evaluated with and without their device. Results: Chronic AFO and FES-users fell 2.50 and 2.77 times more than Non-users. The most robust differences between AFO/FES-users and Non-users were 1) Reduced capacity to stabilize the trunk through reduction in forward whole-body angular momentum and 2) diminished capability to prepare and generate a second step using the paretic leg. Provocatively, the removal of AFO and FES devices did not decease/increase falls or change kinematics. Significance: It is well-established that AFOs/FES devices have a positive impact on static balance and decrease community falls by increasing toe clearance thus preventing trips/stumbles. However, our results suggest that once a trip occurs, these devices do not adequately assist recovery of balance. Specifically, current AFO and FES devices do not assist with second step generation or trunk control. Future studies should explore new devices or training paradigms that target enhancing trunk control and paretic compensatory stepping to decrease falls in this population.
AB - Background: Ankle-foot-orthoses (AFOs) and functional electrical stimulators (FES) are commonly prescribed to treat foot-drop in individuals with stroke. Despite well-established positive impacts of AFO and FES devices on balance and gait, AFO and FES-users still fall at a high rate. Objective: The objective of this study was to investigate 1) the underlying biomechanical mechanisms leading to a fall in long-term AFO and FES-users with chronic stroke and 2) the impacts of AFOs and FES devices on fall outcomes and compensatory stepping response of long-term users with chronic stroke. Methods: Fall outcomes as well as kinematics and kinetics of compensatory stepping response of 42 individuals with chronic stroke (14 AFO-users, 10 FES-users, 18 Non-users) were evaluated during trip-like treadmill perturbations. AFO and FES-users were evaluated with and without their device. Results: Chronic AFO and FES-users fell 2.50 and 2.77 times more than Non-users. The most robust differences between AFO/FES-users and Non-users were 1) Reduced capacity to stabilize the trunk through reduction in forward whole-body angular momentum and 2) diminished capability to prepare and generate a second step using the paretic leg. Provocatively, the removal of AFO and FES devices did not decease/increase falls or change kinematics. Significance: It is well-established that AFOs/FES devices have a positive impact on static balance and decrease community falls by increasing toe clearance thus preventing trips/stumbles. However, our results suggest that once a trip occurs, these devices do not adequately assist recovery of balance. Specifically, current AFO and FES devices do not assist with second step generation or trunk control. Future studies should explore new devices or training paradigms that target enhancing trunk control and paretic compensatory stepping to decrease falls in this population.
KW - Ankle foot orthosis
KW - Fall biomechanics
KW - Functional electrical stimulation
KW - Reactive stepping response
KW - Stroke rehabilitation
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U2 - 10.1016/j.gaitpost.2021.11.025
DO - 10.1016/j.gaitpost.2021.11.025
M3 - Article
C2 - 34847412
AN - SCOPUS:85119981357
SN - 0966-6362
VL - 92
SP - 144
EP - 152
JO - Gait and Posture
JF - Gait and Posture
ER -