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Neural multicontact cuff electrodes have the potential to activate selectively different groups of muscles and offer more possibilities of electrical configurations compared to whole ring cuffs. Several previous studies explored multicontact electrodes with a limited set of configurations which were sorted using a selectivity index only. The objective of the present study is to classify a larger number of configurations, i.e. the way the current is spread over the 12 contacts of the cuff electrode, using additional criteria such as robustness (i.e. ability to maintain selectivity within a range of current amplitudes) and efficiency (i.e. electrical consumption of the considered multipolar configuration versus the electrical consumption of the reference whole-ring configuration). Experiments were performed on the sciatic nerve of 4 rabbits. Results indicated that the optimal configuration depends on the weights applied to selectivity, robustness and efficiency criteria. Tripolar transverse is the most robust configuration and the less efficient, whereas tripolar longitudinal ring is efficient but not robust. New configurations issued from a previous theoretical study we carried out such as steering current ring appears as good compromise between the 3 criteria. [ABSTRACT FROM AUTHOR]

Most of the studies using functional electrical stimulation (FES) in gait rehabilitation have been focused on correcting the drop foot syndrome. Using FES to control the knee joint in individuals with central nervous system (CNS) disorders could also play a key role in gait recovery: spasticity decrease, higher range of motion, positive effect on balance, limiting hyperextension and flexion in stance phase, reducing joint overload, etc. In stance phase, an accurate timing and a fine tuning of stimulation parameters are however required to provide a proper control of the knee stimulation while ensuring a safe and efficient support. In this study, 11 participants were equipped with inertial measurements units (IMU) and foot pressure insoles after supratentorial ischemic or hemorrhagic stroke, informing on knee angle and gait events used to online adapt FES during a 10 m walking protocol. Asymmetry of stance time and weight bearing were monitored as well as gait quality and physiological cost through a series of relevant markers. Vertical trunk motion has been significantly reduced during gait with FES (p-value = 0.038). Despite no significant improvement of stance phase asymmetry has been found, this preliminary work shows evidence of promising technical and rehabilitative potentials of a sensor-based multichannel FES system to control knee joint in post-stroke gait. [ABSTRACT FROM AUTHOR]

Objective Eighty percent of poststroke patients are temporarily unable to walk without help, often with a dropfoot during the midswing phase. Functional electrical stimulation (FES) induces compensation of dropfoot by preprogrammed fixed stimulation, however they are not more effective than mechanical ankle foot orthesis. FES has the advantage of being able to provoke a physiological muscular contraction and respect the articular amplitude. Our objective is to evaluate the metrological quality of the inertial sensors for movement reconstruction in comparison to the gold standard motion analysis. The aim is to improve the SEF using adaptive triggers for dorsiflexion, in hemiplegic poststroke patients. Material/patients and methods Adults with supratentorial ischaemic or hemorrhagic stroke, presenting a foot-drop, able to walk 10 metres without human help, with or without a walking stick were included from May 2016 to June 2017. Patients with ankle dorsiflexion < 0° in knee extension were excluded. Synchronous gait analysis was performed using the VICON © system, the GAITRITE © walkway system and Fox Hikob inertial measurement unit (IMU). The main outcome is the measurement error for the dorsiflexion angle at the heel strike and midswing phase. Results Eleven patients included so far, 7 right sided hemiplegia, 8 male, mean age 56 years. To compare the IMU with the gold standard VICON, the measurement errors were estimated by Blant Altman analysis. Dorsiflexion angle measurements demonstrated a bias of 0.43° between the two techniques, with the limits of agreement [−13.46°; + 14.32°] during stance phases and a bias of 0.72° with agreement values [−16.19°; + 17.64°] during swing phases. Discussion, conclusion The data treatment algorithms from IMU seem to be effective in measuring ankle dorsiflexion with small biases between techniques. The limits of agreement are too wide from a clinical perspective, probably due to a small sample size, but are narrow enough to warrant further technological research. Analysis of the full sample size will provide further information on the limits of agreement. [ABSTRACT FROM AUTHOR]