Combining Intensive Rehabilitation With a Nonfunctional Isokinetic Strengthening Program in Adolescents With Cerebral Palsy: Protocol for a Randomized Controlled Trial.

BACKGROUND: Cerebral palsy is the most common brain injury in the pediatric population. Patients with cerebral palsy present different affectations such as decreased muscle strength, gait deviations, impaired proprioception, and spasticity. Isokinetic strengthening programs combined with intensive rehabilitation may improve muscle strength and therefore gait efficiency. OBJECTIVE: The primary aim of this randomized controlled trial is to compare the effect of an intensive rehabilitation combined with a nonfunctional isokinetic progressive strengthening program to an intensive rehabilitation alone on gait parameters and muscle strength in patients with cerebral palsy. Another goal of this study is to determine whether adding an isokinetic program to intensive rehabilitation is more effective than intensive rehabilitation alone at decreasing spasticity and improving joint position sense in patients with cerebral palsy. METHODS: A total of 30 adolescents with spastic diplegia cerebral palsy (Gross Motor Function Classification System levels I to III) will be randomized, by an independent researcher, into a 3-week intensive rehabilitation and isokinetic progressive strengthening group or an intensive rehabilitation control group. Gait parameters, muscle strength, spasticity, and knee joint position sense will be assessed. These variables will be evaluated at baseline (T0) and at the end of the intervention (T1). The intensive rehabilitation will consist of physiotherapy sessions twice a day and hydrotherapy and virtual reality gait training once a day. The isokinetic training group will have a total of 9 supervised isokinetic strength training sessions focusing on knee flexors and extensors with different execution speeds. RESULTS: The protocol has been accepted by the French National Ethics Committee in October 2022. The inclusion of patients will start in November 2022. CONCLUSIONS: The combination of intensive rehabilitation with an isokinetic program on knee flexors and extensors has not been studied yet. The findings of this study may determine if an isokinetic strength training program of knee flexors and extensors is beneficial for the improvement of gait parameters, muscle strength, spasticity, and joint position sense in adolescents with spastic diplegia. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/43221.

A Novel Framework for Quantifying Accuracy and Precision of Event Detection Algorithms in FES-Cycling.

Functional electrical stimulation (FES) is a technique used in rehabilitation, allowing the recreation or facilitation of a movement or function, by electrically inducing the activation of targeted muscles. FES during cycling often uses activation patterns which are based on the crank angle of the pedals. Dynamic changes in their underlying predefined geometrical models (e.g., change in seating position) can lead to desynchronised contractions. Adaptive algorithms with a real-time interpretation of anatomical segments can avoid this and open new possibilities for the automatic design of stimulation patterns. However, their ability to accurately and precisely detect stimulation triggering events has to be evaluated in order to ensure their adaptability to real-case applications in various conditions. In this study, three algorithms (Hilbert, BSgonio, and Gait Cycle Index (GCI) Observer) were evaluated on passive cycling inertial data of six participants with spinal cord injury (SCI). For standardised comparison, a linear phase reference baseline was used to define target events (i.e., 10%, 40%, 60%, and 90% of the cycle's progress). Limits of agreement (LoA) of ±10% of the cycle's duration and Lin's concordance correlation coefficient (CCC) were used to evaluate the accuracy and precision of the algorithm's event detections. The delays in the detection were determined for each algorithm over 780 events. Analysis showed that the Hilbert and BSgonio algorithms validated the selected criteria (LoA: +5.17/-6.34% and +2.25/-2.51%, respectively), while the GCI Observer did not (LoA: +8.59/-27.89%). When evaluating control algorithms, it is paramount to define appropriate criteria in the context of the targeted practical application. To this end, normalising delays in event detection to the cycle's duration enables the use of a criterion that stays invariable to changes in cadence. Lin's CCC, comparing both linear correlation and strength of agreement between methods, also provides a reliable way of confirming comparisons between new control methods and an existing reference.

A Sensor-Based Multichannel FES System to Control Knee Joint and Reduce Stance Phase Asymmetry in Post-Stroke Gait.

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.

Wireless Electrical Stimulators and Sensors Network for Closed Loop Control in Rehabilitation.

This paper presents a wireless distributed Functional Electrical Stimulation (FES) architecture. It is based on a set of, potentially heterogeneous, distributed stimulation and measurement units managed by a wearable controller. Through a proof-of-concept application, the characterization of the wireless network performances was assessed to check the adequacy of this solution with open-loop and closed-loop control requirements. We show the guaranteed time performances over the network through the control of quadriceps and hamstrings stimulation parameters based on the monitoring of the knee joint angle. Our solution intends to be a tool for researchers and therapists to develop closed-loop control algorithms and strategies for rehabilitation, allowing the design of wearable systems for a daily use context.

Training with FES-assisted cycling in a subject with spinal cord injury: Psychological, physical and physiological considerations.

CONTEXT: People with spinal cord injury (SCI) experience the effects of a sedentary lifestyle very early on. Literature data suggest that programs using FES-assisted cycling would contribute to reduce the consequences of physical inactivity. The objective was to assess the feasibility of 12-month training on a FES-assisted bike of a subject with paraplegia for 21 years, T3, Asia Impairment Scale (AIS) A. An evaluation of morbidity, self-esteem, satisfaction, quality of life and duration of pedaling was performed. The impact on pain, cardiorespiratory function, body composition and bone metabolism were also assessed. FINDINGS: The acceptability score of the training constraints increased from 51 to 59/65 and satisfaction was high around 8/10. The pedaling duration increased from 1' to 26' on the recumbent bike and from 1' to 15' on open terrain. No significant changes were found with BMD and cardiorespiratory measures during exercise tests. SF 36 showed significant improvement of more than 10% and the Rosenberg Self Esteem score rapidly improved from 36 to 39/40. At the end of the training, the patient reached the objective of the Cybathlon 2016 by covering 750 m in less than 8 minutes, at an average speed of 5.80 km/hr. CONCLUSION/CLINICAL RELEVANCE: A person with high and complete level of SCI for more than 20 years can undertake this type of challenge if the prerequisites are met; this training is without danger if the safety precautions are respected; the challenge of participating in a competition had a powerful impact on JP's self-esteem and perceived quality of life.

Inertial measurement unit compared to an optical motion capturing system in post-stroke individuals with foot-drop syndrome.

BACKGROUND: Functional electrical stimulation (FES) can be used for compensation of foot-drop for post-stroke individuals by pre-programmed fixed stimulation; however, this stimulation seems no more effective than mechanical ankle foot orthoses. OBJECTIVE: We evaluated the metrological quality of inertial sensors for movement reconstruction as compared with the gold-standard motion capturing system, to couple FES with inertial sensors to improve dorsiflexion on the paretic side, by using an adaptive stimulation taking into account individuals' performance post-stroke. METHODS: Adults with ischemic or hemorrhagic stroke presenting foot-drop and able to walk 10m, were included from May 2016 to June 2017. Those with passive ankle dorsiflexion<0° with the knee stretched were excluded. Synchronous gait was analyzed with the VICON© system as the gold standard and inertial measurement units (IMUs) worn by participants. The main outcome was the dorsiflexion angle at the heel strike and mid-swing phase obtained from IMUs and the VICON system. Secondary outcomes were: stride length, walking speed, maximal ankle dorsiflexion velocity and fatigue detection. RESULTS: We included 26 participants [18 males; mean age 58 (range 45-84) years]. During heel strike, the dorsiflexion angle measurements demonstrated a root mean square error (RMSE) of 5.5°; a mean average error (MAE) of 3.9°; Bland-Altman bias of -0.1° with limits of agreement -10.9° to+10.7° and good intra-class correlation coefficient (ICC) at 0.87 between the 2 techniques. During the mid-swing phase, the RMSE was 5.6; MAE 3.7°; Bland-Altman bias -0.9° with limits of agreement -11.7° to+9.8° and ICC 0.88. Good agreement was demonstrated for secondary outcomes and fatigue detection. CONCLUSIONS: IMU-based reconstruction algorithms were effective in measuring ankle dorsiflexion with small biases and good ICCs in adults with ischemic or hemorrhagic stroke presenting foot-drop. The precision obtained is sufficient to observe the fatigue influence on the dorsiflexion and therefore to use IMUs to adapt FES.

FES-Induced Cycling in Complete SCI: A Simpler Control Method Based on Inertial Sensors.

This article introduces a novel approach for a functional electrical stimulation (FES) controller intended for FES-induced cycling based on inertial measurement units (IMUs). This study aims at simplifying the design of electrical stimulation timing patterns while providing a method that can be adapted to different users and devices. In most of studies and commercial devices, the crank angle is used as an input to trigger stimulation onset. We propose instead to use thigh inclination as the reference information to build stimulation timing patterns. The tilting angles of both thighs are estimated from one inertial sensor located above each knee. An IF-THEN rule algorithm detects, online and automatically, the thigh peak angles in order to start and stop the stimulation of quadriceps muscles, depending on these events. One participant with complete paraplegia was included and was able to propel a recumbent trike using the proposed approach after a very short setting time. This new modality opens the way for a simpler and user-friendly method to automatically design FES-induced cycling stimulation patterns, adapted to clinical use, for multiple bike geometries and user morphologies.

Effects of Sensitive Electrical Stimulation-Based Somatosensory Cueing in Parkinson's Disease Gait and Freezing of Gait Assessment.

This study aims to investigate the effect of a somatosensory cueing on gait disorders in subjects with Parkinson's disease (PD). After having performed stepping in place and timed up and go assessing tasks, 13 participants with PD were equipped with an electrical stimulator and an inertial measurement unit (IMU) located under the lateral malleolus on the sagittal plane. Electrodes were positioned under the arch of the foot and electrical stimulation (ES) parameters (five 500 µs/phase charge-balanced biphasic pulses delivered at 200 Hz, repeated four times at 10 Hz) adjusted to deliver a sensitive signal. Online IMU signal was processed in order to trigger ES at heel off detection. Starting from a quiet standing posture, subjects were asked to walk at their preferred speed on a path including 5 m straight line, u-turn, and walk around tasks. Three situations were considered: no stimulation baseline precondition (C0), ES condition (C1), and no stimulation baseline post-condition (C0bis), for eliminating a learning effect possibility. In ES condition (C1) the time to execute the different tasks was globally decreased in all the subjects (n = 13). Participants' results were then grouped regarding whether they experienced freezing of gait (FOG) or not during C0 no stimulation baseline precondition. In "freezer" subjects (n = 9), the time to complete the entire path was reduced by 19%. FOG episodes occurrence was decreased by 12% compared to baseline conditions. This preliminary work showed a positive global effect on gait and FOG in PD by a somatosensory cueing based on sensitive electrical stimulation.

Participation to the first Cybathlon: an overview of the FREEWHEELS team FES-cycling solution.

This article is a contribution to a special issue aiming at collecting data and documenting the different specificities of the teams which participated into Cybathlon 2016 FES-bike discipline. Our team prepared one paraplegic pilot over one year and developed a FES-cycling device based on existing commercial products. Our pilot (47 y.o, spinal cord lesion T3 AIS A since year 1995) was qualified for the final race and finished in 6th position over 12 participants in the discipline, covering a total distance of 750m at an average speed of 5.71km/h, propelled by his own quadriceps and hamstrings muscles.

Effects of Sensitive Electrical Stimulation Based Cueing in Parkinson's Disease: A Preliminary Study.

This study aims to investigate the effect of a sensitive cueing on Freezing of Gait (FOG) and gait disorders in subjects suffering from Parkinson's disease (PD). 13 participants with Parkinson's disease were equipped with an electrical stimulator and a foot mounted inertial measurement unit (IMU). An IMU based algorithm triggered in real time an electrical stimulus applied on the arch of foot at heel off detection. Starting from standing, subjects were asked to walk at their preferred speed on a path comprising 5m straight, u-turn and walk around tasks. Cueing globally decreased the time to achieve the different tasks in all the subjects. In "freezer" subjects, the time to complete the entire path was reduced by 19%. FOG events occurrence was lowered by 12% compared to baseline before and after cueing. This preliminary work showed a positive global effect of an electrical stimulation based cueing on gait and FOG in PD.

Robust Foot Clearance Estimation Based on the Integration of Foot-Mounted IMU Acceleration Data.

This paper introduces a method for the robust estimation of foot clearance during walking, using a single inertial measurement unit (IMU) placed on the subject's foot. The proposed solution is based on double integration and drift cancellation of foot acceleration signals. The method is insensitive to misalignment of IMU axes with respect to foot axes. Details are provided regarding calibration and signal processing procedures. Experimental validation was performed on 10 healthy subjects under three walking conditions: normal, fast and with obstacles. Foot clearance estimation results were compared to measurements from an optical motion capture system. The mean error between them is significantly less than 15 % under the various walking conditions.

Detection of freezing of gait in Parkinson disease: preliminary results.

Freezing of gait (FOG) is a common symptom in Parkinsonism, which affects the gait pattern and is associated to a fall risk. Automatized FOG episode detection would allow systematic assessment of patient state and objective evaluation of the clinical effects of treatments. Techniques have been proposed in the literature to identify FOG episodes based on the frequency properties of inertial sensor signals. Our objective here is to adapt and extend these FOG detectors in order to include other associated gait pattern changes, like festination. The proposed approach is based on a single wireless inertial sensor placed on the patient's lower limbs. The preliminary experimental results show that existing frequency-based freezing detectors are not sufficient to detect all FOG and festination episodes and that the observation of some gait parameters such as stride length and cadence are valuable inputs to anticipate the occurrence of upcoming FOG events.