The stiffness of an Ankle-Foot-Orthosis (AFO) that aims to assist walking affects the gait biomechanics of patients with impaired gait. In patients with equinus (spastic paresis of the lower leg), impaired gait is a consequence of an increased passive ankle joint stiffness (originated from calf muscles) in combination with reduced active muscle strength. Though standard AFOs affect clinically relevant improvements of gait parameters, their designs interfere with the range of motion of the ankle joint. We hypothesize that, by lowering the total passive ankle joint stiffness with the AFO, patient's active range of motion will increase while supporting the patients' muscle forces during gait. We propose a novel AFO design with negative stiffness (nAFO) produced by a spring-loaded CAM follower mechanism. The aim of the device is to compensate for the passive stiffness caused by the calf muscles. This study describes the design, evaluation and walk-ability of the prototype nAFO. Results of the evaluation showed the required compensatory negative stiffness -57.4Nm. Rad^-1 (in patients up to 76Nm. Rad-¹) to balance plantar-flexion torque along the range of motion for walking (0.44rad [25°] plantar-flexion to 0.33rad [19°] dorsi-flexion). Assessment on a healthy subject showed passive compensation up to 43.87%. During gait, Tibialis Anterior muscle forces were supported by the nAFO, as observed by a reduced electromyographic signal during swing phase. Though hysteresis of the device has to be reduced, the possibility to compensate for high passive joint stiffness shows promise to increase the active range of motion of the ankle of patients with equinus.

Background and Objective. Favorable prognosis of the upper limb depends on preservation or return of voluntary finger extension (FE) early after stroke. The present study aimed to determine the effects of modified constraint-induced movement therapy (mCIMT) and electromyography-triggered neuromuscular stimulation (EMG-NMS) on upper limb capacity early poststroke. Methods. A total of 159 ischemic stroke patients were included: 58 patients with a favorable prognosis (>10° of FE) were randomly allocated to 3 weeks of mCIMT or usual care only; 101 patients with an unfavorable prognosis were allocated to 3-week EMG-NMS or usual care only. Both interventions started within 14 days poststroke, lasted up until 5 weeks, focused at preservation or return of FE. Results. Upper limb capacity was measured with the Action Research Arm Test (ARAT), assessed weekly within the first 5 weeks poststroke and at postassessments at 8, 12, and 26 weeks. Clinically relevant differences in ARAT in favor of mCIMT were found after 5, 8, and 12 weeks poststroke (respectively, 6, 7, and 7 points; P