Low Cost, User-Controlled Peroneal Stimulator for Foot Drop in Patients With Stroke

Foot drop is a common disabling condition following stroke. It has been conventionally managed using an ankle foot orthosis (AFO). An alternate rehabilitation option is the functional electrical stimulation (FES) systems that has undergone numerous improvisations over past few decades to make it more efficient and user friendly. This chapter aims to evaluate a prototype low-cost FES device in an Indian rehabilitation set-up to match the patients' cultural and socio-economic needs. It illustrates a pilot study designed to test the orthotic and clinical efficacy of the device in terms of dynamic ankle angle change during ambulation and comparing the walking speed and endurance with the AFO. A significant change with nearly two-thirds of normal ankle angle change during swing phase of the gait cycle was observed with nearly equivalent orthotic effects in terms of walking endurance and speed. In terms of receptivity, the device received a mixed response from the patients regarding its effectiveness as an orthosis.

Use and usability of custom-made knee-ankle-foot orthoses in polio survivors with knee instability: A cross-sectional survey

Objective: To investigate the use of custom-made knee-ankle-foot-orthoses in daily life and differences in usability factors of knee-ankle-foot-orthoses between users and discontinued users. Design: Cross-sectional survey study. Subjects: A total of 163 polio survivors provided with a knee-ankle-foot-orthosis at an outpatient clinic of a university hospital. Methods: Use and usability of knee-ankle-foot-orthoses in daily life were assessed with a postal questionnaire. Usability factors were formulated using the International Organization for Standardization (ISO) 9241-11 standard. Results: A total of 106 respondents (65%) returned the questionnaire. Of these, 98 were eligible for analysis. Seventy-four respondents (76%) reported using their knee-ankle-foot-orthosis. Compared with discontinued users (24%), users experienced more limitations when walking without an orthosis (p = 0.001), were more often experienced with wearing a previous orthosis (p < 0.001) and were more often prescribed with a locked rather than a stance-control knee-ankle-foot-orthosis (p = 0.015). Furthermore, users reported better effectiveness of their knee-ankle-foot-orthosis (p < 0.001), more satisfaction with goals of use and knee-ankle-foot-orthosis-related aspects (p < 0.001). Conclusion: The majority of polio survivors used their custom-made knee-ankle-foot-orthoses in daily life. Factors related to continued use, such as walking ability without orthosis, expectations of the orthosis, previous orthosis experience and type of knee-ankle-foot-orthosis provided, should be considered and discussed when prescribing a knee-ankle-foot-orthosis in polio survivors.

Implementation of robotic ankle–foot orthosis with an impedance-based assist-as-needed control strategy

In this paper, a robotic ankle–foot orthosis (AFO) is developed for individuals with a paretic ankle, and an impedance-based assist-as-needed controller is designed for the robotic AFO to provide adaptive assistance. First, a description of the robotic AFO hardware design is presented. Next, the design of the finite state machine is introduced, followed by an introduction to the modelling of the robotic AFO. Additionally, the control of the robotic AFO is presented. An impedance-based high-level controller that is composed of an ankle impedance based torque generation controller and an impedance controller is designed for the high-level control. A compensated low-level controller that is composed of a braking controller and a proportional-derivative controller with a compensation part is designed for the low-level control. Finally, a pilot study is conducted, and the experimental results demonstrate that with the proposed control algorithm, the robotic AFO has the potential for ankle rehabilitation by providing adaptive assistance. In the assisted condition with a high level of assistance, reductions of 8% and 20.1% of the root mean square of the tibialis anterior and lateral soleus activities are observed, respectively.

Design and Initial Validation of a Multiple Degree-of-Freedom Joint for an Ankle-Foot Orthosis

This paper presents the novel design of a Multi-Degree-Of-Freedom joint (M-DOF) for an Ankle-Foot Orthosis (AFO) that aims to improve upon the commercially available Double Action Joint (DAJ). The M-DOF is designed to maintain the functionality of the DAJ, while increasing dorsiflexion stiffness and introducing inversion/eversion. This increase in range of motion is designed to produce greater engagement from lower limb muscles during gait. The M-DOF was experimentally validated with one able-bodied and one stroke subject. Across walking speeds, the M-DOF AFO minimally affected the able-bodied subject's joint kinematics. The stroke subject's ankle dorsiflexion/plantarflexion and knee flexion were not heavily altered when wearing the M-DOF AFO, compared to the DAJ AFO. The new DOF allowed by the M-DOF AFO increased the inversion/eversion of the ankle by ~3°, without introducing any new compensations compared to their gait with the DAJ AFO.