Sensory substitution of elbow proprioception to improve myoelectric control of upper limb prosthesis: experiment on healthy subjects and amputees.

BACKGROUND: Current myoelectric prostheses lack proprioceptive information and rely on vision for their control. Sensory substitution is increasingly developed with non-invasive vibrotactile or electrotactile feedback, but most systems are designed for grasping or object discriminations, and few were tested for online control in amputees. The objective of this work was evaluate the effect of a novel vibrotactile feedback on the accuracy of myoelectric control of a virtual elbow by healthy subjects and participants with an upper-limb amputation at humeral level. METHODS: Sixteen, healthy participants and 7 transhumeral amputees performed myoelectric control of a virtual arm under different feedback conditions: vision alone (VIS), vibration alone (VIB), vision plus vibration (VIS + VIB), or no feedback at all (NO). Reach accuracy was evaluated by angular errors during discrete as well as back and forth movements. Healthy participants' workloads were assessed with the NASA-TLX questionnaire, and feedback conditions were ranked according to preference at the end of the experiment. RESULTS: Reach errors were higher in NO than in VIB, indicating that our vibrotactile feedback improved performance as compared to no feedback. Conditions VIS and VIS+VIB display similar levels of performance and produced lower errors than in VIB. Vision remains therefore critical to maintain good performance, which is not ameliorated nor deteriorated by the addition of vibrotactile feedback. The workload associated with VIB was higher than for VIS and VIS+VIB, which did not differ from each other. 62.5% of healthy subjects preferred the VIS+VIB condition, and ranked VIS and VIB second and third, respectively. CONCLUSION: Our novel vibrotactile feedback improved myoelectric control of a virtual elbow as compared to no feedback. Although vision remained critical, the addition of vibrotactile feedback did not improve nor deteriorate the control and was preferred by participants. Longer training should improve performances with VIB alone and reduce the need of vision for close-loop prosthesis control.

Correction to: Effect of vibration characteristics and vibror arrangement on the tactile perception of the upper arm in healthy subjects and upper limb amputees.

The original article [1] contained an error whereby the captions to Fig. 3 and Fig. 8 were mistakenly interchanged.

Spinopelvic sagittal alignment of patients with transfemoral amputation.

PURPOSE: This study aims to describe the spinopelvic sagittal alignment in transfemoral amputees (TFAs) from a radiologic study of the spine with a postural approach to better understand the high prevalence of low back pain (LBP) in this population. METHODS: TFAs underwent X-rays with 3-D reconstructions of the full spine and pelvis. Sagittal parameters were analyzed and compared to the literature. Differences between TFAs with and without LBP were also observed. RESULTS: Twelve subjects have been prospectively included (TFA-LBP group (n = 5) and TFA-NoP group (n = 7)). Four of the five subjects of the TFA-LBP group and two of the seven in TFAs-NoP group had an imbalanced sagittal posture, especially regarding the T9-tilt, significantly higher in the TFA-LBP group than in the TFA-NoP (p = 0.046). Eight subjects (6 TFA-NoP and 2 TFA-LBP) had abnormal low value of thoracic kyphosis (TK). Moreover, the mean angle of TK in the TFA-NoP group was lower than in the TFA-LBP group (p = 0.0511). CONCLUSION: In the considered sample, TFAs often present a sagittal imbalance. A low TK angle seems to be associated with the absence of LBP. It can be hypothesized that this compensatory mechanism of the sagittal imbalance is the most accessible in this population. This study emphasizes the importance of considering the sagittal balance of the pelvis and the spine in patients with a TFA to better understand the high prevalence of LBP in this population. It should be completed by the analysis of the spinopelvic balance and the lower limbs in 3D. These slides can be retrieved under Electronic Supplementary Material.

Effect of vibration characteristics and vibror arrangement on the tactile perception of the upper arm in healthy subjects and upper limb amputees.

BACKGROUND: Vibrotactile stimulation is a promising venue in the field of prosthetics to retrain sensory feedback deficits following amputation. Discrimination is well established at the forearm level but not at the upper arm level. Moreover, the effects of combining vibration characteristics such as duration and intensity has never been investigated. METHOD: We conducted experiments on spatial discrimination (experiment 1) and tactile intensity perception (experiment 2), using 9 combinations of 3 intensities and 3 durations of vibror stimulations device. Those combinations were tested under 4 arrangements with an array of 6 vibrors. In both experiments, linear orientation aligned with the upper arm longitudinal axis were compared to circular orientation on the upper arm circumference. For both orientations, vibrors were placed either with 3cm space between the center of 2 vibrors or proportionally to the length or the circumference of the subject upper arm. Eleven heathy subjects underwent the 2 experiments and 7 amputees (humeral level) participated in the spatial discrimination task with the best arrangement found. RESULTS: Experiment 1 revealed that circular arrangements elicited better scores than the linear ones. Arrangements with vibrors spaced proportionally elicited better scores (up to 75% correct) than those with 3 cm spacing. Experiment 2, showed that the perceived intensity of the vibration increases with the intensity of the vibrors' activation, but also with their duration of activation. The 7 patients obtained high scores (up to 91.67% correct) with the circular proportional (CP) arrangement. DISCUSSION: These results highlight that discrete and short vibrations can be well discriminated by healthy subjects and people with an upper limb amputation. These new characteristics of vibrations have great potential for future sensory substitution application in closed-loop prosthetic control.

[Amputation, a multidisciplinary treatment]. / L'amputation, une prise en charge multidisciplinaire.

With more than 8000 new amputees each year in France, mostly as a result of a trauma or vascular problem, the challenges are both surgical and technological. The success of the rehabilitation and readjustment of the patient is the fruit of multidisciplinary care.

Chronic Low Back Pain: A Narrative Review of Recent International Guidelines for Diagnosis and Conservative Treatment.

Chronic low back pain (cLBP) is a public and occupational health problem that is a major professional, economic and social burden. We aimed to provide a critical overview of current international recommendations regarding the management of non-specific cLBP. We conducted a narrative review of international guidelines for the diagnosis and conservative treatment of people with non-specific cLBP. Our literature search yielded five reviews of guidelines published between 2018 and 2021. In these five reviews, we identified eight international guidelines that fulfilled our selection criteria. We added the 2021 French guidelines into our analysis. Regarding diagnosis, most international guidelines recommend searching for so-called yellow, blue and black flags, in order to stratify the risk of chronicity and/or persistent disability. The relevance of clinical examination and imaging are under debate. Regarding management, most international guidelines recommend non-pharmacological treatments, including exercise therapy, physical activity, physiotherapy and education; however, multidisciplinary rehabilitation, in selected cases, is the core treatment recommended for people with non-specific cLBP. Oral, topical or injected pharmacological treatments are under debate, and may be offered to selected and well-phenotyped patients. The diagnosis of people with cLBP may lack precision. All guidelines recommend multimodal management. In clinical practice, the management of individuals with non-specific cLBP should combine non-pharmacological and pharmacological treatments. Future research should focus on improving tailorization.

Experimental characterization of the moment-angle curve during level and slope locomotion of transtibial amputee: Which parameters can be extracted to quantify the adaptations of microprocessor prosthetic ankle?

In case of transtibial amputation, the deficit resulting from the loss of the lower limb can be partly compensated with a prosthetic foot and adapted rehabilitation. New prosthetic feet have been developed for transtibial amputees to mimic ankle adaptability to varying terrain. Among them, Microprocessor Prosthetic Ankles (MPA) have a microprocessor to control an electric or a hydraulic actuator to adapt ankle kinematics in stairs and slopes. The objective is to investigate parameters extracted from the moment-angle curve (MAC) and use them to compare 3 MPA during level and slope locomotion against energy storing and return (ESR) foot. Five persons with lower limb transtibial amputation successively fitted with 3 MPA (Propriofoot™, Elan™, Meridium™) compared to their ESR foot. The participants had 2 weeks of adaptation before data acquisition and then a 3 week wash-out period. Range of motion, equilibrium point, hysteresis, late stance energy released, and quasi-stiffness were computed on level ground and 12% slope (upward and downward) thanks to the MAC at the ankle. The study shows the relevance of MAC parameters to evaluate the behavior of MPA. In particular, compared to ESR, all MPA tested in the present study demonstrated a better angle adaptation between walking conditions but a decrease of available energy for the propulsion. Among MPA, main results were: (i) for the Propriofoot™: an adaptation of the ankle angle without modification of the pattern of the MAC (ii) for the Elan™: a limited adaptation of the range of motion but a modification of the energy released (iii) for the Meridium™, the highest adaptation of the range of motion but the lowest available energy of propulsion. One of the main findings of the research is to show and quantify the relationship between range of motion and energy available when using different prosthetic feet in different walking conditions.

Core qualities of an educational program to reduce fears and beliefs of GPs about low back pain: Results of a GPs, experts and literature survey.

BACKGROUND: Despite the fact that non-specific low back pain (LBP) is a frequent symptom, its management remains suboptimal in primary care. A plausible reason is the persistence of erroneous fears and beliefs among general practitioners (GPs). OBJECTIVE: We aimed to determine the core qualities an educational program should have to reduce erroneous fears and beliefs about LBP among GPs. METHODS: We used a two step-approach. In the first step, meaningful qualities were collected using comprehensive data source triangulation from GPs, experts and literature. In the second step, qualities were extracted by three independent investigators in a standardized manner using the Template for Intervention Description and Replication checklist. RESULTS: Qualities were collected from 8 GPs, 24 experts and 15 articles. Extraction revealed a wide range of qualities depending on participants' background and literature. After consensus between investigators, the most meaningful qualities included evidence-based messages and web-based interventions (videos and classes) delivered by a multidisciplinary panel of experts. We found no systematic trend for when and how much, and how to tailor the intervention. CONCLUSIONS: Data source triangulation revealed that the core qualities of an educational program targeting fears and beliefs about LBP among GPs should include evidence-based information, web-based interventions and a multidisciplinary panel of experts. Our findings will help us to design a provisional targeted educational intervention. This will be further assessed in a mixed-method feasibility study and then in a randomized controlled trial.

Two new risk factors for heterotopic ossification development after severe burns.

OBJECTIVES: Life after severe burns is conditioned by the remaining sequelae. The pathophysiology and risk factors of Heterotopic Ossification (HO) after burns are still poorly understood. The aim of this study was to determine: 1) the incidence of HO after burns and 2) the risk factors associated with HO development, in a large retrospective study. METHODS: A case-control study of patients admitted to the burns intensive care unit of Percy Hospital, Paris, from the 1st January 2009 to the 31st December 2013 and then admitted to one of three centres specialised in the rehabilitation of patients with burns. Multivariate analysis was carried out to analyse the relationship between HO development and demographic and clinical data. RESULTS: 805 patients were included. 32 patients (4.0%) developed a total of 74 heterotopic ossifications, that is a little higher incidence than the incidence found in the literature. The epidemiological characteristics of the population studied was similar to the literature. HOs were mainly localized around the elbows, followed by the hips, shoulders and knees. Each case-patient was paired with 3 control-patients. There were significant associations between HO development and the length of stay in the burns intensive care unit, the extent and depth of the burns, the occurrence of pulmonary or cutaneous infections, use of curare and use of an air-fluidized bed. CONCLUSION: In addition to recognized risk factors (duration of stay in the intensive care burns unit, extent and depth of burns, pulmonary and cutaneous infections), the use of curare and the use of a fluidized bed (with the duration of use) were significantly associated with HO formation.

[Rehabilitation after a war injury]. / Des blessés jeunes et sportifs polytraumatisés « de la tête aux pieds ¼.

Rehabilitation after a war injury. Combat wounds can be the cause of serious physical and mental trauma. Injuries caused by the explosion of improvised devices are responsible for multiple penetrating injuries, limb amputations, brain or spinal-cord injuries, and sometimes severe burns. The performance of protective equipment and the effectiveness of the initial medical care allow those injured to survive, often at the cost of severely compromised functional prognoses. Following critical and surgical care, the multidisciplinary teams of Physical Medicine and Rehabilitation (PM et R) intervene with the wounded to initiate rehabilitation and assist with social and occupational reintegration. This support takes place in two steps: the primary phase of "acute rehabilitation" is aimed at preventing and treating complications and starting to relearn activities of daily living; the second phase of "rehabilitation-reintegration" encompasses both the medical and social fields. The implementation of individualized rehabilitation requires the collaboration of PM et R and psychiatric teams, along with various officials within the military institution. New processes specific to the military environment and adapted to the war wounded have been developed: the creation of the War Wounded Rehabilitation and Reintegration Unit (C2RBO: Cellule de Réadaptation et Réinsertion des Blessés en Opération); the use of new technologies and funding of bionic prostheses for amputees; the development of sports rehabilitation programs; the creation of tools to promote social and family reintegration; and the improved recognition of and compensation for injuries. In parallel, the care connection has been reorganized to create a "Defense Rehabilitation Pole" underpinned by a territorial network ensuring the implementation of a care course for every injured soldier, from the initial care in the Parisian military hospital complex to the military medical centers closer to the forces.

Rééducation et réadaptation après une blessure de guerre. Le blessé de guerre est un traumatisé grave à la fois physique et psychique. Les blessures sont souvent provoquées par l'explosion d'engins improvisés responsables de lésions multiples et pénétrantes, d'amputations de membre, de traumatismes crâniens ou vertébro-médullaires et parfois de brûlures graves. La performance des équipements de protection et l'efficacité de la prise en charge médicale initiale permettent à ces blessés de survivre, souvent au prix d'un pronostic fonctionnel sévèrement engagé. Après la prise en charge critique réanimatoire et chirurgicale, les équipes pluridisciplinaires de médecine physique et de réadaptation (MPR) interviennent auprès des blessés pour initier la rééducation et les accompagner jusqu'à la réinsertion socio-professionnelle. Cette prise en charge se déroule en deux temps : les phases primaires de « rééducation initiale ¼ visent à prévenir et traiter les complications médico-chirurgicales et à débuter les actions d'autonomisation du blessé dans les activités quotidiennes ; les phases secondaires dites de réadaptation-réinsertion entrent dans le champ du médico-social. La mise en oeuvre des projets de réadaptation personnalisés nécessite la collaboration des équipes de MPR et de psychiatrie avec les différents acteurs sociaux de l'institution militaire. De nouveaux processus spécifiques au milieu militaire et adaptés au blessé de guerre ont été développés : la création de la Cellule de réadaptation et réinsertion des blessés en opération dite C2RBO, le recours aux nouvelles technologies et le financement des prothèses bioniques chez l'amputé, le développement de la réinsertion par le sport, la création d'outils favorisant la réinsertion socio-familiale et l'amélioration des processus de reconnaissance et de réparation du préjudice. En parallèle, le réseau de soins est réorganisé pour créer à terme un véritable « Pôle de réhabilitation de la défense ¼ sous-tendu par un maillage territorial garantissant la mise en oeuvre d'un parcours de soins adapté à chaque blessé, depuis sa prise en charge initiale sur l'ensemble hospitalier militaire parisien, jusqu'au plus près des forces, dans les centres médicaux des armées.

Spasticity: revisiting the role and the individual value of several pharmacological treatments.

Though in the last few decades only a few new drugs have come available for the treatment of spasticity, new insights may revise the role and individual value of several pharmacological treatments. Diazepam, baclofen and tizanidine are the most prescribed drugs for the treatment of spasticity. Intrathecal baclofen and local infiltration of botulin toxin are added values in selective patients. Gabapentin is a novelty, and the working mechanism of cannabis has been elucidated. Dantrolene sodium appears to owe its selectivity from the recently discovered ryanodine receptor, with a peripheral effect in muscles. In this review the pathophysiology and epidemiology of spasticity, pharmacology, clinical efficacy and unwanted effects of the different drugs for spasticity are updated.

Pain immediately upon sitting down and relieved by standing up is often associated with radiologic lumbar instability or marked anterior loss of disc space.

STUDY DESIGN: Comparison of functional radiographs in consecutive patients with low back pain with or without pain on sitting down and relieved by standing up. OBJECTIVES: To detect radiologic signs possibly associated with a clinical symptom. SUMMARY OF BACKGROUND DATA: No link has been established between increased vertebral mobility and a specific pain pattern or a clinical symptom. METHODS: Forty-two patients seen consecutively with low back pain occurring immediately on sitting down and relieved on standing up were compared with 32 controls whose low back pain did not show this pattern. Dynamic radiographs were taken in extension, erect, flexion, and sitting in the painful position. The segments thought to be responsible for the pain were identified by comparing clinical, radiographic, and magnetic resonance data. Endplate angles, rotation, and translation were measured. The radiographs were read twice each by two independent observers. RESULTS: Eighty-six percent (95% confidence interval, 72-99%) of the patients with the symptom were female. The segments identified as the source of pain were as follows: L4-L5 in 20 cases and L1-L2 to L3-L4 in 22 cases. Mean rotation of these segments was 13.9 +/- 4.5 degrees in the patient group versus 7.5 +/- 4.3 degrees in the control group (P < 0.001). In 14% of the patients (vs. 3% of controls), it exceeded 20 degrees (P = 0.13). Anterior or posterior translation >10% was seen in 31% of the patients (vs. 0% of controls; P < 0.001). In flexion, the endplate angle was -5.2 +/- 3.6 degrees (patients) versus 1.2 +/- 5.7 degrees (controls) (P < 0.01) and <-5 degrees in 55% of patients versus 12.5% of controls (P < 0.001). This value of <-5 degrees was associated with marked anterior loss of disc space. CONCLUSION: Low back pain occurring immediately on sitting down and relieved on standing up was statistically associated with instability (specificity 100%, sensitivity 31%) or marked anterior loss of disc space in flexion (specificity 87%, sensitivity 55%).