David Gasq

Background: Functional electrical stimulation (FES) can improve gait in children with cerebral palsy (CP), but gait impairments vary widely between individuals and likely require stimulation of different muscle groups. Delivering real‐time, multichannel, gait‐triggered stimulation remains difficult to implement in clinical practice. This study explores the technical feasibility of using gait analysis systems commonly available in pediatric rehabilitation centers to drive multichannel FES. The temporal performance of a real‐time, gait‐triggered system based on kinematic event detection was evaluated. Methods: Retrospective gait data from 30 children with CP were replayed to emulate real‐time acquisition. A custom algorithm detected gait events (initial contact and a knee flexion threshold) and triggered an eight‐channel stimulator whose output was recorded via an acquisition card through resistors. Hardware delays were measured across each stage: triggering function, command transmission, and stimulation onset, as well as overall system latency. Results: A total of 1100 gait cycles were analyzed. The mean global latency was 50.33 ms (SD 7.55 ms). Most stimulations occurred within 70 ms (99.45%), and all within 100 ms. The main source of delay was command transmission to the stimulator, while algorithm processing contributed minimally. Performance was consistent across triggering conditions. Conclusion: The proposed approach enables reliable real‐time gait‐event detection and electrical stimulation triggering with latencies compatible with future clinical application. These results highlight the potential of using gait analysis platforms to flexibly explore and optimize personalized multichannel stimulation strategies, while assessing their immediate orthotic effects prior to translation of the most effective strategies into wearable systems.

Notre objectif a été d'étudier l'apport d'une analyse temps-fréquence par transformée en ondelettes dans l'évaluation stabilométrique de la stabilité posturale de sujets présentant une pathologie neurologique. A partir d'un corpus de données incluant 199 patients présentant une pathologie neurologique et 41 sujets témoins, nous avons étudié la reproductibilité et la validité des paramètres stabilométriques. Nous avons déterminé les valeurs d'erreur de mesure de paramètres issus d'une analyse temps-fréquence, d'une analyse fréquentielle par méthode FFT et d'une analyse linéaire du signal, chez des patients hémiplégiques vasculaires. Pour la moyenne de 3 acquisitions de 30 secondes, nous proposons de privilégier l'utilisation de paramètres issus d'une analyse temps-fréquence qui sont les plus reproductibles. L'évaluation stabilométrique a montré un intérêt au moins équivalent aux critères cliniques dans la prédiction du risque de chute chez le patient hémiplégique vasculaire. Le modèle de prédiction reste cependant insuffisant pour être appliqué de manière isolé en pratique clinique, où une évaluation multi-modale du patient reste nécessaire. Une étude des déterminants neurologiques et biomécaniques de la distribution du contenu fréquentiel a été réalisée avec l'analyse en ondelettes. Nous avons montré qu'en l'absence de tremblement postural caractérisé, la distribution du contenu fréquentiel était essentiellement liée au degré d'instabilité posturale. Nos perspectives sont d'approfondir l'intérêt de l'analyse temps-fréquence par transformée en ondelettes, qui permet d'étudier à la fois la stabilité posturale et les mécanismes de contrôle sous-jacents.

Objective . Brain-computer interface (BCI)-based interventions show growing evidence of efficacy for post-stroke upper-limb rehabilitation by closing the sensorimotor loop and promoting neuroplasticity. Despite this promise, their clinical uptake remains limited. This study aimed to identify the determinants of BCI acceptability among stroke survivors in order to inform user-centred neurotechnology design and facilitate clinical adoption. Approach . We conducted a mixed-methods study combining a large-scale questionnaire ( N = 140) and semi-structured interviews ( N = 12) with stroke survivors. The questionnaire was grounded in a validated theoretical model of BCI acceptability and assessed the determinants of three core constructs: intention to use (IU), perceived usefulness (PU), and perceived ease of use (PEOU). Qualitative data were analysed using thematic framework analysis to enrich and contextualise the quantitative findings. Main Results . Overall, stroke survivors reported high acceptability of BCI-based rehabilitation, with strong IU (mean IU = 8.48/10). Quantitative analyses showed that IU was primarily driven by PU, itself strongly influenced by perceived scientific relevance and, to a lesser extent, by individual factors such as autonomy, self-efficacy, and technology-related anxiety. PEOU was mainly determined by ease of learning and computer playfulness, but did not directly predict IU. Qualitative findings complemented these results by highlighting the importance of perceived innovativeness, the perception of directly engaging brain activity, visibility of progress, and clear scientific evidence. Interviews also emphasised the need for intuitive interfaces, clear instructions, short sessions, and appropriate therapeutic support to sustain engagement. Significance . These findings underscore that successful adoption of BCI-based rehabilitation requires more than technological performance alone. Enhancing acceptability among stroke survivors calls for: (i) goal-oriented and evidence-based rehabilitation protocols; (ii) clear communication of scientific rationale and outcomes to reinforce trust and social acceptance; and (iii) user-friendly system design that supports learning, autonomy, and self-efficacy while minimising cognitive and physical burden.

Background: Hemiparetic gait is characterized by reduced limb shortening during swing, increasing the risk of tripping and leading to compensatory strategies. Despite 3D gait analysis being the gold standard for gait assessment, there is no consensus on relevant kinematic biomarkers for limb shortening and compensatory movements. Methods: Systematic review querying five databases (PubMed, Cochrane, Scopus, PEDro, and Web of Science). We included articles that described at least one kinematic biomarker of the lower limb in the sagittal plane and at least one biomarker of the lower limb or pelvis in the transversal or frontal plane, or pelvis in the sagittal plane. Then, we collected kinematic biomarkers from these studies and identified those that seemed relevant to describe limb shortening and compensatory movements during the swing phase. Results: We included 40 studies and collected 385 biomarkers. Among them, 15 described limb shortening, 22 compensations, and 3 toe clearance. Analysis of 12 interventional studies showed that some biomarkers of shortening and compensation were more sensitive to change than others. Conclusions: This review highlights the lack of standardized description for limb shortening and compensatory movements in hemiparetic gait. A set of 13 relevant biomarkers is proposed to improve the interpretation of gait analysis and support consistent evaluation of therapeutic interventions.

BackgroundStroke is the leading cause of acquired motor deficiencies in adults. Restoring prehension abilities is challenging for individuals who have not recovered active hand opening capacities after their rehabilitation. Self-triggered functional electrical stimulation applied to finger extensor muscles to restore grasping abilities in daily life is called grasp neuroprosthesis (GNP) and remains poorly accessible to the post-stroke population. Thus, we developed a GNP prototype with self-triggering control modalities adapted to the characteristics of the post-stroke population and assessed its impact on abilities.MethodsThrough two clinical research protocols, 22 stroke participants used the GNP and its control modalities (EMG activity of a pre-defined muscle, IMU motion detection, foot switches and voice commands) for 3 to 5 sessions over a week. The NeuroPrehens software interpreted user commands through input signals from electromyographic, inertial, foot switches or microphone sensors to trigger an external electrical stimulator using two bipolar channels with surface electrodes. Users tested a panel of 9 control modalities, subjectively evaluated in ease-of-use and reliability with scores out of 10 and selected a preferred one before training with the GNP to perform functional unimanual standardized prehension tasks in a seated position. The responsiveness and functional impact of the GNP were assessed through a posteriori analysis of video recordings of these tasks across the two blinded evaluation multi-crossover N-of-1 randomized controlled trials.ResultsNon-paretic foot triggering, whether from EMG or IMU, received the highest scores in both ease-of-use (median scores out of 10: EMG 10, IMU 9) and reliability (EMG 9, IMU 9) and were found viable and appreciated by users, like voice control and head lateral inclination modalities. The assessment of the system's general responsiveness combined with the control modalities latencies revealed median (95% confidence interval) durations between user intent and FES triggering of 333 ms (211 to 561), 217 ms (167 to 355) and 467 ms (147 to 728) for the IMU, EMG and voice control types of modalities, respectively. The functional improvement with the use of the GNP was significant in the two prehension tasks evaluated, with a median (95% confidence interval) improvement of 3 (- 1 to 5) points out of 5.ConclusionsThe GNP prototype and its control modalities were well suited to the post-stroke population in terms of self-triggering, responsiveness and restoration of functional grasping abilities. A wearable version of this device is being developed to improve prehension abilities at home.Trial Registration: Both studies are registered on clinicaltrials.gov: NCT03946488, registered May 10, 2019 and NCT04804384, registered March 18, 2021.ConclusionsThe GNP prototype and its control modalities were well suited to the post-stroke population in terms of self-triggering, responsiveness and restoration of functional grasping abilities. A wearable version of this device is being developed to improve prehension abilities at home.Trial Registration: Both studies are registered on clinicaltrials.gov: NCT03946488, registered May 10, 2019 and NCT04804384, registered March 18, 2021.

Article: ToulGaitViz: a tool for the systematic description of lower limb clearance during the swing phase of hemiparetic gait after stroke. A cohort study - European Journal of Physical and Rehabilitation Medicine 2023 Oct 23 - Minerva Medica - Journals

Accurate assessment of upper-limb movement alterations is a key component of post-stroke follow-up. Motion capture (MoCap) is the gold standard for assessment even in clinical conditions, but it requires a laboratory setting with a relatively complex implementation. Alternatively, inertial measurement units (IMUs) are the subject of growing interest, but their accuracy remains to be challenged. This study aims to assess the minimal detectable change (MDC) between spatiotemporal and quality variables obtained from these IMUs and MoCap, based on a specific protocol of IMU calibration and measurement and on data processing using the dead reckoning method. We also studied the influence of each data processing step on the level of between-system MDC. Fifteen post-stroke hemiparetic subjects performed reach or grasp tasks. The MDC for the movement time, index of curvature, smoothness (studied through the number of submovements), and trunk contribution was equal to 10.83%, 3.62%, 39.62%, and 25.11%, respectively. All calibration and data processing steps played a significant role in increasing the agreement. The between-system MDC values were found to be lower or comparable to the between-session MDC values obtained with MoCap, meaning that our results provide strong evidence that using IMUs with the proposed calibration and processing steps can successfully and accurately assess upper-limb movement alterations after stroke in clinical routine care conditions.

Paired associative stimulation (PAS) is an intervention that modulates cortical plasticity. Motor imagery (MI) is used in the rehabilitation of stroke patients. We aimed to evaluate the possible synergistic effect of associating both interventions for potentiating motor recovery poststroke. MIPAS is a single-center, randomized controlled trial that enrolled 24 hemiparetic poststroke participants. Three single-session interventions were tested in a crossover design: PAS/MI, PAS, and ShamPAS/MI during which the affected Extensor Carpi Radialis (ECR) muscle was targeted. During MI, the participants were instructed to imagine extending their paretic wrist. We used Sham, subthreshold stimulation during ShamPAS. Changes in ECR Motor-Evoked Potential (MEP) areas and paretic wrist Range of Motion (aROM) during active extension were compared between the interventions. We observed no significant superior effect of any intervention, neither on MEP nor on wrist aROM. A time of assessment effect was highlighted for both outcome measures, with MEP- and aROM-measured post-interventions significantly higher than those measured pre-intervention. Despite the beneficial effect of each intervention on participant paretic wrist motor function, not always associated with MEP change, our results do not highlight a specific advantage in combining PAS and MI interventions in post-stroke motor rehabilitation.

Neuromuscular disease and peripheral neuropathy may cause drop foot with or without evertor weakness. We developed a helical-shaped, non-articulated ankle–foot orthosis (AFO) to provide medial–lateral stability while allowing mobility, to improve gait capacity. Our aim was to evaluate the effect of the helical AFO (hAFO) on functional gait capacity (6-min walk test) in people with peripheral neuropathy or neuromuscular disease (NMD) causing unilateral drop foot and compare with a posterior leaf spring AFO (plsAFO). Secondary aims were to compare functional mobility, 3D kinematic and kinetic gait variables and satisfaction between the AFOs. Single centre, randomised crossover trial from January to July 2017 in 20 individuals (14 with peripheral neuropathy and 6 with NMD, 12 females, mean age 55.6 years, SD 15.3); 10 wore the hAFO for the first week and 10 wore the plsAFO before switching for the second week. The 6-min walk test (6MWT), Timed Up and Go (TUG) test and 3D gait analysis were evaluated with the hAFO, the plsAFO and shoes only (noAFO) at inclusion and 1 week after wearing each orthosis. Satisfaction was evaluated with the Quebec user evaluation of satisfaction with assistive technology (QUEST). Median [interquartile range] 6MWT distance was greater with the hAFO (444 m [79]) than the plsAFO (389 m [135], P < 0.001, Hedge’s g = 0.6) and noAFO (337 m [91], P < 0.001, g = 0.88). TUG time was shorter with the hAFO (8.1 s [2.8]) than the plsAFO (9.5 s [2.6], P < 0.001, g = − 0.5) and noAFO (10.0 s [2.6]), P < 0.001, g = − 0.6). The plsAFO limited plantarflexion during the loading response (plsAFO − 7.5 deg [6.0] vs. noAFO -13.0 deg [10.0], P = 0.0007, g = − 1.0) but the hAFO did not (− 11.0 deg [5.1] vs. noAFO, P = 0.05, g = − 0.5). Quasi-stiffness was lower for the hAFO than plsAFO (P = 0.009, g = − 0.7). The dimensionless eversion moment was higher (though not significantly) with the hAFO than noAFO. Neither orthosis reduced ankle power (P = 0.34). Median total QUEST score was higher for the hAFO (4.7 [0.7]) than the plsAFO (3.6 [0.8]) (P < 0.001, g = 1.9). The helical orthosis significantly and considerably improved functional gait performance, did not limit ankle mobility, increased lateral stability, though not significantly, and was associated with greater patient satisfaction than the posterior leaf spring orthosis. Trial registration The trial began before registration was mandatory