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Abstract Background Falls due to stumbling are prevalent for transfemoral prosthesis users and may lead to increased injury risk. This preliminary case series analyzes the transfemoral prosthesis user stumble recovery response to highlight key deficits in current commercially-available prostheses and proposes potential interventions to improve recovery outcomes. Methods Six transfemoral prosthesis users were perturbed on their prosthetic limb at least three times while walking on a treadmill using obstacle perturbations in early, mid and late swing. Kinematic data were collected to characterize the response, while fall rate and key kinematic recovery metrics were used to assess the quality of recovery and highlight functional deficits in current commercially-available prostheses. Results Across all participants, 13 (54%) of the 24 trials resulted in a fall (defined as > 50% body-weight support) with all but one participant (83%) falling at least once and two participants (33%) falling every time. In contrast, in a previous study of seven young, unimpaired, non-prosthesis users using the same experimental apparatus, no falls occurred across 190 trials. For the transfemoral prosthesis users, early swing had the highest rate of falling at 64%, followed by mid-swing at 57%, and then late swing at 33%. The trend in falls was mirrored by the kinematic recovery metrics (peak trunk angle, peak trunk angular velocity, forward reach of the perturbed limb, and knee angle at ground contact). In early swing all four metrics were deficient compared to non-prosthesis user controls. In mid swing, all but trunk angular velocity were deficient. In late swing only forward reach was deficient. Conclusion Based on the stumble recovery responses, four potential deficiencies were identified in the response of the knee prostheses: (1) insufficient resistance to stance knee flexion upon ground contact; (2) insufficient swing extension after a perturbation; (3) difficulty initiating swing flexion following a perturbation; and (4) excessive impedance against swing flexion in early swing preventing the potential utilization of the elevating strategy. Each of these issues can potentially be addressed by mechanical or mechatronic changes to prosthetic design to improve quality of recovery and reduce the likelihood a fall.

OBJECTIVES:. To review recruitment and retention strategies of randomized family-centered interventional studies in adult ICUs. DATA SOURCES:. The MEDLINE, Embase, PsycINFO, CINAHL, and the Cochrane Library database from inception to February 2023. STUDY SELECTION:. Randomized controlled trials with family-centered interventions in the ICU setting that reported at least one family-centered outcome that were included in our previously published systematic review. DATA EXTRACTION:. For recruitment: Number of family members approached and enrolled, type of approach, location, time of day approached, whether medical team approached first, compensation offered, and type of consent. For retention: Number of family members enrolled and completed initial follow-up visit, mode of follow-up, location of follow-up visit, data collection method, timing of follow-up visits, number of follow-up visits, and compensation offered. Recruitment (participants approached/enrolled) and retention (participants enrolled/completed initial follow-up) percentage were calculated. DATA SYNTHESIS:. There were 51 studies in the analysis. The mean recruitment percentage was 49.3% ± 24.3%. There were no differences in recruitment percentage by study country, ICU type, recruitment approach, or whether the medical team approached the family member first (all p > 0.05). The mean retention percentage for the initial follow-up visit was 81.6% ± 18.0%. There were no differences in retention percentage by mode of participant contact, data collection type, or follow-up location (all p > 0.05). Minimal data were available to determine the impact of time of day approached and compensation on recruitment and retention outcomes. CONCLUSIONS:. About half of family members of ICU patients approached participated in trials and more than eight in ten completed the initial follow-up visit. We did not identify specific factors that impacted family recruitment or retention. There is a strong need for further studies to characterize optimal strategies to ensure family participation in clinical trials.

This work proposes a new swing controller for semi-powered low impedance transfemoral prostheses that resolves the issue of potentially competing inputs between artificial assistive power and user-sourced power. Rather than add power as an exogeneous input, the control approach uses power to modify the homogeneous portion of the shank dynamics, and therefore need not construct or curate an input that is coordinated with user input. The implemented controller requires a single control parameter at a given walking speed, where the value of that parameter is a function of walking speed, as determined by an adaptive algorithm, such that peak knee angles are commensurate with walking-speed-dependent behaviors of individuals without any negative gait pathologies. The controller and parameter selection algorithm are described in the paper, and subsequently validated in walking experiments with three participants with unilateral transfemoral amputation. The experiments demonstrate that the proposed controller increases peak knee angle and minimum toe clearance during swing phase without increasing hip compensatory actions, relative to the users’ daily-use devices.

Abstract Engaging family members in care improves person- and family-centered outcomes. Many healthcare professionals have limited awareness of the role and potential benefit of family engagement in care. This review describes the rationale for engaging families in care, and opportunities to engage family in various clinical care settings during training and early career practice.

Background: Observational studies have shown an association between family participation in intensive care unit (ICU) rounds and better family-centred outcomes. However, evidence from randomized studies on the impact of family participation in ICU rounds is lacking. The objective of this pilot study was to evaluate the feasibility of a randomized trial for family participation in ICU rounds and obtain preliminary estimates of effect to inform a future effectiveness trial. Methods: Family members of patients in the cardiovascular ICU at an academic tertiary-care hospital were randomized to the intervention (participation in rounds) or usual-care group. Following ICU discharge, family member participants completed the family satisfaction (Family Satisfaction in the Intensive Care Unit Survey [FS-ICU]). Feasibility metrics were recruitment (≥ 10 participants per month), uptake (≥ 80%), and follow-up (≥ 80%). Effectiveness was measured by between-group differences in survey score at follow-up. Results: A total of 27 participants were recruited over 8 weeks. A total of 44% of family members (27 of 61) who were approached agreed to participate. Nonparticipation was due most commonly to lack of interest (N = 20; 64%). All family members randomized to the intervention (N = 16) were present for rounds (100% uptake). Follow-up data were available for 23 participants (85%). Family members who participated in rounds had a higher level of satisfaction with care, compared to the usual-care group (87.3 vs 74.7, P = 0.03, respectively). Conclusions: Family participation in cardiovascular ICU rounds is feasible and effective at improving family satisfaction. Our findings will inform the design of a planned, larger, multicentre study to evaluate the effectiveness of family participation in ICU rounds to improve family-centred outcomes. Trial registration number: NCT05528185. Résumé: Contexte: Des études d’observation ont montré qu’il y avait un lien entre une participation des familles aux tournées à l’unité des soins intensifs (USI) et de meilleurs résultats centrés sur la famille. Toutefois, il existe peu de données issues d’études à répartition aléatoire sur l’effet d’une participation des familles aux tournées à l’USI. L’objectif de cette étude pilote était d’évaluer la faisabilité d’un essai à répartition aléatoire sur la participation des familles aux tournées à l’USI et d’obtenir des estimations préliminaires de l’effet pour orienter un futur essai sur l’efficacité. Méthodologie: Des membres de la famille de patients admis à l’USI cardiovasculaires d’un hôpital universitaire de soins tertiaires ont été affectés de façon aléatoire à l’intervention (participation aux tournées) ou au groupe de soins habituels. Après la sortie de l’USI, les participants ont rempli le questionnaire sur la satisfaction des familles à l’égard de l’unité des soins intensifs (FS-ICU, pour Family Satisfaction in the Intensive Care Unit). Les paramètres de faisabilité étaient le recrutement (≥ 10 participants par mois), l’adhésion (≥ 80 %) et le suivi (≥ 80 %). L’efficacité a été mesurée par les différences des scores au questionnaire entre les groupes lors du suivi. Résultats: Au total, 27 participants ont été recrutés sur une période de 8 semaines. Chez les membres des familles qui ont été invités à participer, 44 % (27/61) ont accepté. Le refus était le plus souvent attribuable à un manque d’intérêt (n = 20; 64 %). Tous les membres des familles affectés à l’intervention (n = 16) ont été présents pour les tournées (adhésion de 100 %). Des données de suivi ont été obtenues pour 23 participants (85 %). Le taux de satisfaction à l’égard des soins a été plus élevé chez les membres des familles ayant participé aux tournées que dans le groupe de soins habituels (87,3 % contre 74,7 %; p = 0,03; respectivement). Conclusions: La participation des familles aux tournées dans les USI cardiovasculaires est faisable et est efficace pour améliorer la satisfaction des familles. Nos résultats guideront la conception d’une plus grande étude multicentrique planifiée visant à évaluer l’efficacité de la participation des familles aux tournées dans l’USI pour améliorer les résultats centrés sur la famille. Trial registration number: NCT05528185.

BackgroundActivation of a family member refers to their desire, knowledge, confidence, and skills that can inform engagement in healthcare. Family activation combined with opportunity can lead to engagement in care. No tool currently exists to measure family activation in acute care. Therefore, we aimed to develop and validate a tool to measure family activation in acute care.MethodsAn interdisciplinary team of content experts developed the FAMily Activation Measure (FAM-Activate) through an iterative process. The FAM-Activate tool is a 4-item questionnaire with 5 Likert-type response options (ranging from strongly agree to strongly disagree). Scale scores are converted to a 0-100 point scoring range so that higher FAM-Activate scores indicate increased family activation. An overall FAM-Activate score (range 0-100) is calculated by adding the scores for each item and dividing by 4. We conducted reliability and predictive validity assessments to validate the instrument by administering the FAM-Activate tool to family members of patients in an acute cardiac unit at a tertiary care hospital. We obtained preliminary estimates of family engagement and satisfaction with care.ResultsWe surveyed 124 family participants (age 54.1±14.4; 73% women; 34% non-white). Participants were predominantly the adult child (38%) or spouse/partner (36%) of patients. The mean FAM-Activate score during hospitalization was 84.1±16.1. FAM-Activate had acceptable internal consistency (Cronbach's a = 0.74) and showed test-retest responsiveness. FAM-Activate was moderately correlated with engagement behavior (Pearson's correlation r = 0.47, P ConclusionThe FAM-Activate tool was reliable and had predictive validity in the acute cardiac population. Further research is needed to explore whether improving family activation can lead to improved family engagement in care.

Background: Engaging families in care leads to improved patient- and family-centreed outcomes and is recommended by cardiovascular societies. However, no validated tools are currently available to measure family engagement in acute cardiac care. We previously described the development of the FAMily Engagement (FAME) instrument. The purpose of this study is to validate the FAME instrument in acute cardiac care. Methods: The FAME questionnaire was administered to family members of patients in a cardiovascular intensive care unit and ward at an academic tertiary care hospital in Montreal, Canada. After hospital discharge, we assessed family satisfaction in the intensive care unit (FS-ICU) and mental health (using the Hospital Anxiety and Depression Scale [HADS]). Higher FAME scores indicate increased care engagement. Reliability was assessed using internal consistency testing. Predictive validity was evaluated by assessing the relationship between the FAME score and the FS-ICU score and whether the FAME score was correlated with the HADS score. Convergent validity was assessed by comparing the FAME score with engagement elements of the FS-ICU score. Results: A total of 160 family participants were included (age 54.8 ± 14.8 years; 66% women; 36% non-White). The most common relationships to the patient were spouse/partner and adult child (both n = 62; 39%). The mean FAME score was 70.8 ± 16.0. The FAME instrument had high internal consistency (Cronbach’s a = 0.86). The FAME score was associated with family satisfaction in the multivariable analysis (P < 0.001). No correlation occurred between FAME and HADS anxiety or depression scores. Conclusions: The FAME tool demonstrated reliability and convergent and predictive validity in the acute care cardiac population. Further research is needed to explore whether selected engagement interventions can impact the FAME score favourably. Résumé: Contexte: La participation des familles aux soins entraîne une amélioration des résultats centrés sur le patient et sur la famille et est recommandée par les sociétés cardiovasculaires. Cependant, il n’existe actuellement aucun outil validé pour mesurer la participation des familles aux soins cardiaques aigus. Par le passé, nous avons décrit l’élaboration de l’instrument FAMily Engagement (FAME). L’étude dont il est question ici vise à valider l’instrument FAME en contexte de soins cardiaques aigus. Méthodologie: Nous avons soumis le questionnaire FAME aux proches des patients admis aux soins intensifs cardiovasculaires et à l’unité de soins cardiovasculaires dans un hôpital universitaire de soins tertiaires à Montréal, au Canada. Lorsque le patient a reçu son congé de l’hôpital, nous avons évalué la satisfaction de la famille à l’égard de l’unité des soins intensifs (FS-ICU, de l'anglais : family satisfaction in the intensif care unit) de même que l’état de santé mentale (à l’aide de l’échelle d’anxiété et de dépression en milieu hospitalier [EHAD]). Un score élevé au questionnaire FAME indiquait une participation plus active aux soins. La fiabilité a été évaluée selon la méthode de cohérence interne. Pour mesurer la validité prédictive, nous avons étudié le lien entre le score au questionnaire FAME et le score FS-ICU, et déterminé si le score au questionnaire FAME était corrélé au score à l’EHAD. La validité convergente a été évaluée en comparant le score du questionnaire FAME avec les composantes de la participation du score FS-ICU. Résultats: Au total, 160 participants ont été inclus (âge : 54,8 ± 14,8 ans; 66 % de femmes; 36 % de personnes non blanches). En général, les participants étaient soit les conjoint(e)s/partenaires des patients, soit les enfants adultes des patients (n = 62 pour chacun des deux cas; 39 %). Le score FAME moyen était de 70,8 ± 16,0. L’instrument FAME présentait une forte cohérence interne (a de Cronbach = 0,86). Le score FAME était associé à la satisfaction familiale dans l’analyse multivariée (p < 0,001). Aucune corrélation n’a été notée entre le score FAME et les scores de dépression ou d’anxiété de l’EHAD. Conclusions: L’outil FAME a présenté une fiabilité et une validité convergente et prédictive dans la population des patients recevant des soins cardiaques aigus. D’autres recherches sont nécessaires pour déterminer si certaines interventions relatives à la participation peuvent améliorer le score FAME.

Introduction: Family engagement is a goal of care delivery in the intensive care unit (ICU). However, currently, no validated instrument for the ICU is designed specifically to measure family engagement. Our objective was to develop a novel family engagement measure. Methods: The Family Engagement (FAME) tool was developed through an iterative process, with input from experts, family members, and end-users. The FAME questionnaire is composed of 12 items. Each item is scored using a 5-point Likert scale and transformed onto a 0-100-point range, with higher scores indicating greater engagement. We performed a single-site pilot study for family members of patients in a cardiovascular ICU. Results: The FAME tool had a high construct validity and required an average of 3.33 minutes to complete. A total of 32 family members completed the FAME questionnaire (mean age: 52.4 ± 14.2 years; 71.4% female; 47% adult child ; 31% spouse/partner). The overall mean FAME score was 84.0% ± 25.2%. Differences in engagement across various domains were identified. Conclusions: The FAME measure is a focused and pragmatic tool to measure the degree and type of family engagement in care of patients in the ICU. Further studies are needed to evaluate the FAME tool in a larger population. Résumé: Introduction: La participation de la famille est un objectif établi dans la prestation de soins dans les unités de soins intensifs (USI). Pourtant, il n’existe actuellement aucun instrument validé conçu précisément pour mesurer la participation des familles dans les USI. Notre objectif était d’élaborer une nouvelle façon de mesurer la participation des familles. Méthodologie: L’outil Family Engagement (FAME; participation de la famille) a été conçu par un processus itératif, avec la collaboration d’experts, de membres de familles et d’utilisateurs des services. Le questionnaire FAME comporte 12 éléments. Chaque élément est noté à l’aide d’une échelle de Likert en 5 points et transposé en un score de 0 à 100, un score plus élevé indiquant une plus grande participation. Nous avons réalisé une étude pilote dans un seul établissement auprès des membres de la famille de patients d’une USI en cardiologie. Résultats: L’outil FAME avait une bonne validité conceptuelle et nécessitait en moyenne 3,33 minutes à remplir. Au total, 32 membres de la famille ont rempli le questionnaire FAME (âge moyen : 52,4 ± 14,2 ans; 71,4 % de femmes; 47 % d’enfants adultes; 31 % de conjoints). Le score FAME moyen global a été de 84,0 % ± 25,2 %. Des différences quant à la participation aux divers volets ont été relevées. Conclusions: Le questionnaire FAME est un outil ciblé et pratique qui permet de mesurer le degré et le type de participation de la famille dans les soins des patients séjournant à l’USI. D’autres études doivent être menées pour évaluer l’outil FAME au sein d’une population élargie.

Abstract Background Transfemoral prosthesis users’ high fall rate is related to increased injury risk, medical costs, and fear of falling. Better understanding how stumble conditions (e.g., participant age, prosthesis type, side tripped, and swing phase of perturbation) affect transfemoral prosthesis users could provide insight into response deficiencies and inform fall prevention interventions. Methods Six unilateral transfemoral prosthesis users experienced obstacle perturbations to their sound limb in early, mid, and late swing phase. Fall outcome, recovery strategy, and kinematics of each response were recorded to characterize (1) recoveries versus falls for transfemoral prosthesis users and (2) prosthesis user recoveries versus healthy adult recoveries. Results Out of 26 stumbles, 15 resulted in falls with five of six transfemoral prosthesis users falling at least once. By contrast, in a previously published study of seven healthy adults comprising 214 stumbles using the same experimental apparatus, no participants fell. The two oldest prosthesis users fell after every stumble, stumbles in mid swing resulted in the most falls, and prosthesis type was not related to strategy/fall outcomes. Prosthesis users who recovered used the elevating strategy in early swing, lowering strategy in late swing, and elevating or lowering/delayed lowering with hopping in mid swing, but exhibited increased contralateral (prosthetic-side) thigh abduction and trunk flexion relative to healthy controls. Falls occurred if the tripped (sound) limb did not reach ample thigh/knee flexion to sufficiently clear the obstacle in the elevating step, or if the prosthetic limb did not facilitate a successful step response after the initial sound-side elevating or lowering step. Such responses generally led to smaller step lengths, less anterior foot positioning, and more forward trunk flexion/flexion velocity in the resulting foot-strikes. Conclusions Introducing training (e.g., muscle strength or task-specific motor skill) and/or modifying assistive devices (e.g., lower-limb prostheses or exoskeletons) may improve responses for transfemoral prosthesis users. Specifically, training or exoskeleton assistance could help facilitate sufficient thigh/knee flexion for elevating; training or prosthesis assistance could provide support-limb counteracting torques to aid in elevating; and training or prosthesis assistance could help initiate and safely complete prosthetic swing.

Background: Older adults may be subject to prolonged bedrest during hospitalization for acute cardiovascular disease, which can contribute to poor functional outcomes posthospitalization. Our objective was to describe mobility status in hospitalized older adults with acute cardiovascular disease. Methods: Patients aged ≥ 60 years old in the cardiac intensive care unit and cardiovascular ward at a tertiary care academic centre in Montréal, Québec were prospectively enrolled from April 2019 to March 2020. Activity levels were measured with the ActiGraph GT9X Link 3-axis accelerometer (ActiGraph, Pensacola, FL). Sedentary was defined as lying in bed or in a sitting position. Health-related quality of life (HRQOL) was measured with the Short-Form 36 (SF-36) questionnaire by telephone at 1 month posthospitalization. The primary outcome was percentage of sedentary time during hospitalization. Results: There were 35 patients included in the analysis (75.7 ± 6.9 years old; 45.7% female; 22.9% ischemic heart disease; 20.0% heart failure). Patients spent 91.2% ± 5.5 in a sedentary position during their hospital stay. Mean steps per minute were 1.0 ± 1.2, and mean kcals consumed per day were 116.6 ± 124.5. In the multivariable analysis, a higher percentage of sedentary time and lower steps per minute were each associated with lower total SF-36 scores at 1-month posthospitalization (both P < 0.05). Conclusions: Older adults with acute cardiovascular disease may be sedentary for a large part of their hospital stay. Increased sedentary time is associated with worse self-reported posthospital HRQOL. Future studies are needed to determine whether interventions to increase activity during hospitalization improve posthospital HRQOL and functional outcomes. Résumé: Introduction: Les personnes âgées hospitalisées en raison d’une maladie cardiovasculaire en phase aiguë peuvent être sujettes à un alitement prolongé qui peut contribuer à des résultats fonctionnels médiocres après l’hospitalisation. Notre objectif était de décrire l’état de mobilité des personnes âgées hospitalisées en raison d’une maladie cardiovasculaire en phase aiguë. Méthodes: Nous avons inscrit de façon prospective les patients de ≥ 60 ans de l’unité des soins intensifs cardiaques et de l’unité de cardiologie d’un centre universitaire de soins tertiaires à Montréal, au Québec, d’avril 2019 à mars 2020. Nous avons mesuré les niveaux d’activité physique à l’aide de l’accéléromètre ActiGraph GT9X Link 3-axis (ActiGraph, Pensacola, Floride, É.-U.). Nous avons défini la sédentarité par le fait d’être couché au lit ou en position assise. Nous avons mesuré la qualité de vie liée à la santé (QVLS) à l’aide du questionnaire SF-36 (Short Form-36) par téléphone un mois après l’hospitalisation. Le critère de jugement principal était le pourcentage de temps sédentaire durant l’hospitalisation. Résultats: Dans l’analyse, on comptait 35 patients (75,7 ± 6,9 ans; 45,7 % de femmes; 22,9 % atteints d’une cardiopathie ischémique; 20,0 % atteints d’insuffisance cardiaque). Les patients passaient 91,2 % ± 5,5 en position sédentaire durant leur séjour à l’hôpital. Les pas moyens par minute étaient de 1,0 ± 1,2, et les kcal moyennes consommées par jour étaient de 116,6 ± 124,5. Dans l’analyse multivariée, un pourcentage plus élevé de temps sédentaire et un nombre inférieur de pas par minute étaient chacun associés à des scores totaux plus faibles au SF-36 un mois après l’hospitalisation (P

Background: Emerging evidence indicates that engaging family members in early mobilization may benefit both patients and family members. However, little is known about the effect of patient and family-member experience and perspectives on mobilization in acute cardiac care. Our goal was to assess the perspectives and experience of patients and their family members regarding early mobilization in acute cardiac care, to better understand patient-related barriers to mobilization and assist in the development of mobilization strategies that increase family-member engagement in care. Methods: Patient and family-member surveys were developed to assess attitudes and knowledge about mobilization, family-members’ roles in providing care, and mobilization care the patients received. Surveys were distributed to patients and their family members over a 4-month period. Results: A total of 101 participants completed the survey (patients, n = 78; family members, n = 23). Most patients (n = 54; 69.2%) agreed or strongly agreed that early mobilization should be routinely performed. Of 72 patients who underwent early mobilization, 60 (83.3%) felt that mobilization helped their recovery. The majority of family members were interested in being involved with mobilization (n = 19; 82.6%). One quarter of family members felt that mobilizing their relatives too soon after admission was potentially dangerous (n = 6; 26.1%). Conclusions: Most patients wish to be mobilized early after admission, and family members want to participate in mobilization efforts. These findings should inform efforts to overcome patient- and family-related barriers to mobilization. Résumé: Introduction: De nouvelles données révèlent que la participation des membres de la famille à la mobilisation précoce peut profiter aux patients et aux membres de la famille. Toutefois, on en connaît peu sur les effets de l’expérience des patients et des membres de la famille et les points de vue sur la mobilisation aux soins cardiaques de courte durée. Notre but était d’évaluer les points de vue et l’expérience des patients et des membres de la famille quant à la mobilisation précoce en soins cardiaques de courte durée afin de mieux comprendre les obstacles des patients à l’égard de la mobilisation et de contribuer à l’élaboration de stratégies de mobilisation qui accroissent la participation des membres de la famille aux soins. Méthodes: Nous avons élaboré des enquêtes destinées aux patients et aux membres de la famille afin d’évaluer les attitudes et les connaissances à l’égard de la mobilisation, les rôles des membres de la famille dans la prestation des soins et l’expérience des patients quant à la prise en charge de la mobilisation. Nous avons distribué les enquêtes aux patients et aux membres de leur famille au cours d’une période de quatre mois. Résultats: Un total de 101 participants ont rempli l’enquête (patients, n = 78; membres de la famille, n = 23). La plupart des patients (n = 54; 69,2 %) se disaient d’accord ou tout à fait d’accord avec le fait de pratiquer systématiquement la mobilisation précoce. Parmi les 72 patients qui avaient eu une mobilisation précoce, 60 (83,3 %) percevaient que la mobilisation précoce favorisait leur rétablissement. La majorité des membres de la famille souhaitait participer à la mobilisation (n = 19; 82,6 %). Un quart des membres de la famille percevaient que la mobilisation trop hâtive de leur proche après l’admission était potentiellement dangereuse (n = 6; 26,1 %). Conclusions: La plupart des patients souhaitent être mobilisés de façon précoce après l’admission, et les membres de la famille veulent participer aux efforts de mobilisation. Ces résultats devraient orienter les efforts visant à surmonter les obstacles des patients et de la famille à l’égard de la mobilisation.

This article examines the feasibility of employing a cold-gas thruster (CGT), intended as a backpack-wearable device, for purposes of arresting backward falls, and in particular describes a supervisory controller that, for some motion described by an arbitrary combination of center-of-mass angle and angular velocity, both detects an impending fall and determines when to initiate thrust in the CGT in order to arrest the impending fall. The CGT prototype and the supervisory controller are described and experimentally assessed using a rocking block apparatus intended to approximate a backward-falling human. In these experiments, the CGT and supervisory controller restored upright stability to the rocking block in all experiment cases that would have otherwise resulted in a fall without the CGT assistance. Since the controller and experiments employ a reduced-order model of a falling human, the authors also conducted a series of simulations intended to examine the extent to which the controller might remain effective in the case of a multi-segment human. The results of these simulations suggest that the CGT controller would be nearly as effective on a multi-segment falling human as on the reduced-order model.

Falls due to stumbles are a major cause of injury for many populations, and as such interventions to reduce fall risk have been a key focus of rehabilitation research. However, dedicated stumble recovery assistance in a powered lower-limb exoskeleton has yet to be explored as a fall mitigation intervention. Thus young, healthy adults ( $ N=3 $ ) were recruited for a stumble recovery experiment to test the efficacy of knee exoskeleton stumble recovery assistance in improving an impaired stumble recovery response (i.e., the elevating strategy response). Leg weights were attached unilaterally to each participant’s shank to simulate walking and stumble recovery impairment, and a unilateral powered knee exoskeleton was worn on the same leg for walking and stumble recovery assistance. Ultimately, knee exoskeleton stumble recovery assistance served to improve participants’ elevating limb kinematics (i.e., increase thigh and knee motion) and reduce overall fall risk (i.e., reduce trunk motion and improve foot placement) during responses relative to their impaired response (i.e., with the leg weights and no assistance), and relative to their response while receiving only walking assistance. This initial exploration provides a first indication that knee exoskeleton stumble recovery assistance is a viable approach to improving an impaired stumble recovery response, which could serve two important use cases: (1) a safety mechanism for existing exoskeleton wearers, who may be less capable of recovering from stumbles due to the added weight or joint impedance of the device; (2) an external stumble recovery aid for fall-prone populations, such as the elderly or stroke survivors.

This article describes a novel approach to the control of a powered knee prosthesis where the control system provides passive behavior for most activities and then provides powered assistance only for those activities that require them. The control approach presented here is based on the categorization of knee joint function during activities into four behaviors: resistive stance behavior, active stance behavior, ballistic swing, and non-ballistic swing. The approach is further premised on the assumption that healthy non-perturbed swing-phase is characterized by a ballistic swing motion, and therefore, a replacement of that function should be similarly ballistic. The control system utilizes a six-state finite-state machine, where each state provides different constitutive behaviors (concomitant with the four aforementioned knee behaviors) which are appropriate for a range of activities. Transitions between states and torque control within states is controlled by user motion, such that the control system provides, to the extent possible, knee torque behavior as a reaction to user motion, including for powered behaviors. The control system is demonstrated on a novel device that provides a sufficiently low impedance to enable a strictly passive ballistic swing-phase, while also providing sufficiently high torque to offer powered stance-phase knee-extension during activities such as step-over stair ascent. Experiments employing the knee and control system on an individual with transfemoral amputation are presented that compare the functionality of the power-supplemented nominally passive system with that of a conventional passive microprocessor-controlled knee prosthesis.

This article proposes, describes, and tests a swing-assist walking controller for a stance-controlled, swing-assisted knee prosthesis that aims to combine benefits of passive swing mechanics (e.g., quiet operation, biomimetic function, and low power requirements) with benefits of powered swing assistance (e.g., increased robustness of swing-phase motion and specifically increased toe clearance). A three-participant, multislope, multispeed treadmill walking study was performed using the swing-assist prosthesis and controller, as well as using the participants’ prescribed microprocessor knee devices. The swing-assist device and approach were found to improve user minimum foot clearance during walking at slopes and speeds, and also to improve symmetry of knee motion. Hip power inputs from stance knee release to heel strike indicated that, on average, less hip power was required when using the swing-assist prosthesis, indicating that the observed benefits were likely the result of the knee device and its control methodology, rather than a result of increased hip joint effort.

ABSTRACT: Background: Given changes in the care and outcomes of acute myocardial infarction (AMI) patients over the past several decades, we sought to develop prediction models that could be used to generate accurate risk-adjusted mortality and readmission outcomes for hospitals in current practice across Canada. Methods: A Canadian national expert panel was convened to define appropriate AMI patients for reporting and develop prediction models. Preliminary candidate variable evaluation was conducted using Ontario patients hospitalized with a most responsible diagnosis of AMI from April 1, 2015 to March 31, 2018. National data from the Canadian Institute for Health Information was used to develop AMI prediction models. The main outcomes were 30-day all-cause in-hospital mortality and 30-day urgent all-cause readmission. Discrimination of these models (measured by c-statistics) was compared with that of existing Canadian Institute for Health Information models in the same study cohort. Results: The AMI mortality model was assessed in 54,240 Ontario AMI patients and 153,523 AMI patients across Canada. We observed a 30-day in-hospital mortality rate of 6.3%, and a 30-day all-cause urgent readmission rate of 10.7% in Canada. The final Canadian AMI mortality model included 12 variables and had a c-statistic of 0.834. For readmission, the model had 13 variables and a c-statistic of 0.679. Discrimination of the new AMI models had higher c-statistics compared with existing models (c-statistic 0.814 for mortality; 0.673 for readmission). Conclusions: In this national collaboration, we developed mortality and readmission models that are suitable for profiling performance of hospitals treating AMI patients in Canada. RÉSUMÉ: Contexte: Compte tenu des changements apportés au cours des dernières décennies aux soins des patients ayant subi un infarctus aigu du myocarde (IAM) et aux issues d'un tel événement, nous avons voulu élaborer des modèles prédictifs pouvant servir à calculer de façon précise les résultats relatifs à la mortalité et aux réadmissions, ajustés selon les risques, pour les hôpitaux dans la pratique actuelle au Canada. Méthodologie: Un groupe national d'experts canadiens a été mis sur pied et a reçu le mandat de définir les critères appropriés applicables aux patients ayant subi un IAM aux fins de déclaration des cas et d’élaborer des modèles prédictifs. L’évaluation préliminaire des variables proposées a été effectuée à partir de patients hospitalisés en Ontario entre le 1er avril 2015 et le 31 mars 2018 chez lesquels l'IAM était le diagnostic principal à l'origine de l'hospitalisation. Les données à l’échelle nationale de l'Institut canadien d'information sur la santé (ICIS) ont été utilisées pour élaborer des modèles prédictifs d'IAM. Les deux principales issues évaluées étaient la mortalité hospitalière toutes causes confondues à 30 jours et la réadmission urgente toutes causes confondues à 30 jours. Le pouvoir discriminant de ces modèles (mesuré par la statistique C) a été comparé à celui des modèles existants de l'ICIS dans la même cohorte de l’étude. Résultats: Le modèle de mortalité par IAM a été évalué auprès de patients ayant subi un IAM, dont 54 240 en Ontario et 153 523 dans l'ensemble du Canada. Nous avons observé un taux de mortalité hospitalière à 30 jours de 6,3 % et un taux de réadmission urgente à 30 jours toutes causes confondues de 10,7 % au Canada. Le modèle canadien final de prédiction de la mortalité par IAM était constitué de 12 variables et avait une statistique C de 0,834. Pour la réadmission, le modèle comportait 13 variables et présentait une statistique C de 0,679. Le pouvoir discriminant des nouveaux modèles d'IAM présentait une statistique C supérieure à celle des modèles existants (statistique C de 0,814 pour la mortalité et de 0,673 pour la réadmission). Conclusions: Dans le cadre de cette collaboration nationale, nous avons élaboré des modèles prédictifs de la mortalité et de la réadmission hospitalière qui permettent d’établir un profil des résultats obtenus par les hôpitaux traitant des patients ayant subi un IAM au Canada.

Abstract Aim To assess the beliefs, attitudes and knowledge of nurses, physicians and physiotherapists in a cardiovascular intensive care unit (CICU) on patient mobilization. Design Survey of CV healthcare providers in the CICU at two academic tertiary care hospitals. Methods The validated Patient Mobilization Attitudes and Beliefs Survey was distributed to CV providers. The survey is a 26‐item self‐administered questionnaire that assesses providers' perceived barriers in three domains: attitude, behaviour and knowledge. Results Participants (N = 142) completed the survey (nurses, N = 67, physicians, N = 59 and physiotherapists, N = 16; 155 eligible participants, 91.6% overall completion rate). Nurses had lower overall knowledge, attitude and behaviour barriers to mobilization than physicians, but higher than physiotherapists (all p

Background: Early mobilization (EM) is safe and feasible in older adults with acute cardiovascular disease (CVD) and may improve posthospitalization patient-centred outcomes. Our objective was to assess posthospitalization health-related quality of life (HRQOL) in older adults with acute CVD undergoing EM. Methods: Patients aged ≥ 60 years with acute CVD undergoing EM at an academic tertiary centre in Montreal, Quebec were prospectively enrolled from January 2018 to January 2020. Functional status was measured using the validated Level of Function Mobility Scale. HRQOL was measured using the Short-Form 36 questionnaire at 1 and 12 months posthospitalization. The primary outcome was the questionnaire’s physical component summary (PCS) score at 1 month posthospitalization. Results: There were 147 patients included in the analysis (aged 75.0 ± 8.7 years; 44.6% female; 48.6% with ischemic heart disease). The mean 1-month PCS score was 34.7 ± 9.7, which was 11.5 points and 8.4 points lower compared to age-matched Canadian normative data for people ages 65-74 years and ≥ 75 years, respectively. The mean PCS score at 12 months (36.5 ± 9.2) and the mean mental component summary scores at 1 and 12 months (36.9 ± 11.1; 40.5 ± 11.5) were lower than those of the age-matched population (all P < 0.0001). In the multivariable analysis, increased age and worse prehospitalization function were associated with lower PCS score at 1 month. Conclusions: Older adults with acute CVD had lower HRQOL at 1 and 12 months posthospitalization than age-matched Canadian norms. Prehospitalization functional status was predictive of poor posthospitalization HRQOL. The EM program was safe and feasible in this patient population. Further studies are needed to determine whether EM can improve posthospitalization patient-centred outcomes in older adults, particularly those with poor prehospitalization functional status. Résumé: Introduction: La mobilisation précoce (MP) est sécuritaire et réalisable chez les personnes âgées atteintes d’une maladie cardiovasculaire (MCV) aiguë et peut permettre d’améliorer les résultats axés sur les patients après l’hospitalisation. Notre objectif était d’évaluer la qualité de vie liée à la santé (QVLS) après l’hospitalisation chez les personnes âgées atteintes d’une MCV aiguë se soumettant à la MP. Méthodes: Les patients ≥ 60 ans atteints d’une MCV aiguë se soumettant à la MP dans un centre universitaire de soins tertiaires à Montréal, au Québec, ont été inscrits de façon prospective de janvier 2018 à janvier 2020. Nous avons mesuré l’état fonctionnel au moyen de l’échelle de mobilité fonctionnelle validée. Nous avons mesuré la QVLS à l’aide du questionnaire d’évaluation de la santé en version abrégée (SF-36, de l’anglais Short-Form 36 questionnaire) un mois et 12 mois après l’hospitalisation. Le principal critère d’évaluation était les scores du sommaire de la composante physique (SCP) du questionnaire un mois après l’hospitalisation. Résultats: Cent quarante-sept patients ont fait l’objet de l’analyse (âgés de 75,0 ± 8,7 ans; 44,6 % de femmes; 48,6 % atteints d’une cardiopathie ischémique). Les scores moyens du SCP après un mois étaient de 34,7 ± 9,7, soit 11,5 points et 8,4 points plus bas que les données normatives canadiennes appariées selon l’âge pour les personnes de 65 à 74 ans et ≥ 75 ans, et ce, respectivement. Les scores moyens du SCP après 12 mois (36,5 ± 9,2) et les scores moyens du sommaire de la composante mentale après un mois et après 12 mois (36,9 ± 11,1; 40,5 ± 11,5) étaient plus bas que les scores de la population appariée selon l’âge (toutes les P < 0,0001). Dans l’analyse multivariée, l’âge avancé et le plus mauvais fonctionnement avant l’hospitalisation ont été associés à un score plus bas du SCP après un mois. Conclusions: Les personnes âgées atteintes d’une MCV aiguë avaient un mois et 12 mois après l’hospitalisation une QVLS inférieure aux normes canadiennes appariées selon l’âge. L’état fonctionnel avant l’hospitalisation permettait de prédire une QVLS médiocre après l’hospitalisation. Le programme de MP était sécuritaire et réalisable pour ces patients. D’autres études sont nécessaires pour déterminer si la MP peut contribuer à l’amélioration des résultats axés sur les patients après l’hospitalisation chez les personnes âgées, particulièrement chez celles qui ont un état fonctionnel médiocre avant l’hospitalisation.

Background: Screening relatives of patients with ischemic heart disease can identify over half of the population with poorly controlled cardiovascular (CV) risk factors. Family or household members (FMs) may be highly motivated to undergo CV primary prevention screening at the time of their relative’s admission to the Cardiovascular Intensive Care Unit (CICU). Methods: Patients aged ≤ 70 years admitted to a tertiary CICU for an acute coronary event were given a letter to refer FMs for CV screening. Interested FMs underwent CV risk-factor assessment and primary prevention counselling. The objectives were to identify FMs with an intermediate or high modified 10-year Framingham risk score (FRS) and to evaluate whether a family-oriented primary prevention strategy improved CV risk. Results: There were 51 CV probands who referred 101 FMs (62 family, 39 household; mean age: 44.8 ± 15.3; 65 (64.4%) female) for screening. One-third of FMs aged ≥ 30 years (n = 28 of 84; 32.1%) had a new diagnosis of either hypertension, diabetes, or dyslipidemia. Nearly half of FMs (n = 38; 45.2%) had an intermediate or high modified Framingham 10-year CV risk. In FMs aged ≥ 30 years attending the 6-month follow-up (51 of 84; 60.7%), the mean FRS decreased by 4.6% (from 13.2% ± 12.7 to 8.6% ± 10.0, P < 0.001), and 30.4% (7 of 23) of FMs had a low FRS who had initially had an intermediate or high FRS. Conclusions: A patient-led referral strategy at the time of CICU admission led to a high rate of identification of previously undiagnosed CV risk factors in FMs. Implementing a similar referral program on a larger scale could identify a considerable burden of CV risk. Résumé: Contexte: Le dépistage des parents proches de patients atteints de cardiopathie ischémique permet d'identifier plus de la moitié de la population présentant des facteurs de risques cardiovasculaires (CV) mal contrôlés. Les membres de la famille ou du ménage (MF) peuvent se révéler très motivés à se soumettre à un dépistage de prévention CV primaire au moment de l'admission de leur parent proche à l'unité de soins intensifs cardiovasculaires (USCV). Méthodes: Les patients âgés de ≤ 70 ans admis dans une USCV tertiaire pour un événement coronarien aigu ont reçu une lettre les invitant à envoyer des MF pour un dépistage CV. Les MF intéressés ont subi une évaluation des facteurs de risques CV et ont reçu des conseils de prévention primaire. Les objectifs étaient d'identifier les MF présentant un score de risque de Framingham (SRF) modifié intermédiaire ou élevé sur 10 ans et d'évaluer si une stratégie de prévention primaire axée sur le lien familial diminuait le risque CV. Résultats: Cinquante et un (51) sujets ayant des troubles CV ont référé 101 MF (62 membres de la famille, 39 membres du ménage; âge moyen : 44,8 ± 15,3 ans; 65 (64,4 %) femmes) à un dépistage. Un tiers des MF âgés de ≥ 30 ans (n = 28 sur 84; 32,1 %) ont reçu un nouveau diagnostic d'hypertension, de diabète ou de dyslipidémie. Près de la moitié des MF (n = 38; 45,2 %) présentaient un score de risques CV à 10 ans intermédiaire ou élevé, sur l’échelle du score de risque de Framingham (SRF) modifié. Parmi les MF âgés de ≥ 30 ans ayant participé au suivi sur 6 mois (51 sur 84; 60,7 %), le SRF moyen a diminué de 4,6 % (de 13,2 % ± 12,7 à 8,6 % ± 10,0, p < 0,001), et 30,4 % (7 sur 23) des MF avaient un SRF faible après avoir initialement eu un SRF intermédiaire ou élevé. Conclusions: Une stratégie d'orientation effectuée au moment de l'admission du patient à l’USCV a conduit à un taux élevé d'identification de facteurs de risques CV non diagnostiqués auparavant parmi les MF. La mise en œuvre d'un programme d'orientation similaire à plus grande échelle pourrait permettre d'identifier un nombre considérable de personnes à risques CV.

Background: Treatment of ST-elevation myocardial infarction (STEMI) in Canada is protocolized, and timely patient transfer can improve outcomes. Population-based processes of care in Canada for other cardiovascular conditions remain less clear. We aimed to describe the interhospital transfer of Canadian patients with acute cardiovascular disease. Methods: We reviewed the Canadian Institute for Health Information Discharge Abstract Database for adult patients hospitalized with acute cardiovascular disease between 2013 and 2018. We compared patient characteristics and clinical outcomes based on transfer status (transferred, nontransferred) and presenting hospital (teaching, large community, medium community, and small community hospitals). The primary outcome of interest was in-hospital mortality. Results: There were 476,753 patients with primary acute cardiovascular diagnoses, 48,579 (10.2%) of whom were transferred. Transferred patients were more frequently younger, male, and had fewer comorbidities. The most common diagnoses among transferred patients were non-STEMI (44.2%), STEMI (29.0%), and congestive heart failure (9.4%). Using teaching hospitals as a reference, transfer to large and medium community hospitals was associated with lower hospital mortality (adjusted odds ratio: 0.83, 95% confidence interval: 0.75-0.91 and 0.45, 95% confidence interval: 0.39-0.52, respectively). Conclusions: Approximately 10% of patients with acute cardiovascular conditions are transferred to another hospital. Patient transfer may be associated with lower in-hospital mortality, with possible variability based on diagnosis, comorbidities, hospital of origin, and destination hospital. Further investigation into the optimization of care for patients with acute cardiovascular disease, including transfer practices, is warranted as regionalized care models continue to develop. Résumé: Introduction: Au Canada, le traitement de l’infarctus du myocarde avec sus-décalage du segment ST (STEMI) découle d’un protocole qui prévoit au moment opportun le transfert des patients pour permettre d’améliorer les résultats cliniques. On n’en sait encore peu sur les processus de soins auprès de la population canadienne en ce qui concerne les autres maladies cardiovasculaires. Nous avions pour objectif de décrire les transferts interhospitaliers de patients canadiens atteints d’une maladie cardiovasculaire aiguë. Méthodes: Nous avons passé en revue les résumés de la base de données de l’Institut canadien d’information sur la santé sur les congés des patients hospitalisés atteints d’une maladie cardiovasculaire aiguë entre 2013 et 2018. Nous avons comparé les caractéristiques des patients et les résultats cliniques en fonction du statut du transfert (patients transférés ou non transférés) et de l’hôpital de destination (hôpitaux d’enseignement, grands hôpitaux communautaires, hôpitaux communautaires moyens et petits hôpitaux communautaires). Le principal critère étudié était la mortalité intrahospitalière. Résultats: Parmi les 476 753 patients qui avaient un diagnostic principal de maladie cardiovasculaire aiguë, 48 579 (10,2 %) ont été transférés. Les patients transférés étaient plus fréquemment jeunes, de sexe masculin, et avaient peu de comorbidités. Les diagnostics les plus fréquents parmi les patients transférés étaient les non-STEMI (44,2 %), les STEMI (29,0 %) et l’insuffisance cardiaque congestive (9,4 %). En utilisant comme référence les hôpitaux d’enseignement, les transferts vers de grands hôpitaux communautaires et des hôpitaux communautaires moyens étaient associés à une plus faible mortalité intrahospitalière (ratio d’incidence approché ajusté : 0,83, intervalle de confiance à 95 %, 0,75-0,91 et 0,45, intervalle de confiance à 95 %, 0,39-0,52, et ce, respectivement). Conclusions: Approximativement 10 % des patients atteints d’une maladie cardiovasculaire aiguë sont transférés vers un autre hôpital. Le transfert des patients peut être associé à une plus faible mortalité intrahospitalière et montrer une variabilité en fonction du diagnostic, des comorbidités, de l’hôpital d’origine et de l’hôpital de destination. D’autres études liées à l’optimisation des soins des patients atteints d’une maladie cardiovasculaire aiguë, qui porteront de plus sur les pratiques de transfert, sont justifiées puisque l’élaboration de modèles de soins régionaux se poursuit.

Abstract Background The experimental study of stumble recovery is essential to better understanding the reflexive mechanisms that help prevent falls as well as the deficiencies in fall-prone populations. This study would benefit from a system that can introduce perturbations that: 1) are realistic (e.g., obstacle disrupting the foot in swing phase), 2) are unanticipated by subjects, 3) are controllable in their timing, and 4) allow for kinematic and kinetic evaluation. Methods A stumble perturbation system was designed that consists of an obstacle delivery apparatus that releases an obstacle onto a force-instrumented treadmill and a predictive targeting algorithm which controls the timing of the perturbation to the foot during swing phase. Seven healthy subjects were recruited to take part in an experimental protocol for system validation, which consisted of two sub-experiments. First, a perception experiment determined whether subjects could perceive the obstacle as it slid onto the treadmill belt. Second, a perturbation experiment assessed the timing accuracy of perturbations relative to a target percent swing input by the experimenter. Data from this experiment were then used to demonstrate that joint kinematics and kinetics could be computed before and after the perturbation. Results Out of 168 perception trials (24 per subject), not a single obstacle was perceived entering the treadmill by the subjects. Out of 196 perturbation trials, 190 trials successfully induced a stumble event, with a mean targeting accuracy, relative to the desired percent swing, of 25 ms (6.2% of swing phase). Joint kinematic and kinetic results were then computed for three common stumble recovery strategies and shown to be qualitatively consistent with results from prior stumble studies conducted overground. Conclusions The stumble perturbation system successfully introduced realistic obstacle perturbations that were unanticipated by subjects. The targeting accuracy substantially reduced mistrials (i.e., trials that did not elicit a stumble) compared to previous studies. This accuracy enables stumble recovery to be studied more systematically as a function of when the perturbation occurs during swing phase. Lastly, joint kinematic and kinetic estimates allow for a comprehensive analysis of stumble recovery biomechanics.

Bedrest and immobilization following a myocardial infarction (MI) can lead to functional impairment that can persist following hospitalization. Early mobilization (EM) is associated with good functional and clinical outcomes in critical care, medical and surgical settings. However, the impact and current role of EM in post-MI care has not been well-defined. Our objective was to assess the evidence for post-MI mobilization, define current post-MI mobilization practice, and understand perspectives of cardiovascular professionals toward mobilization. A scoping review related to "early mobilization" and "myocardial infarction" was performed using the Joanna Briggs Institute Methodology. Pubmed, Embase, Google Scholar, Cochrane Library and CINAHL databases were included. Results were categorized into six topic areas. There were 59 references included in the analysis. There was evidence for the effectiveness and safety of earlier mobilization in experimental studies of the pre-revascularization era, but there was a lack of strong evidence for EM in contemporary post-MI care. Mobilization appears to be safe following arterial catheterization and is associated with minimal hemodynamic and respiratory compromise. Most people are delayed in mobilizing post-MI and spend the majority of the initial hospitalization period lying in bed. Only 1 of 7 current major cardiovascular professional societies guidelines recommend EM post-MI. There were no studies exploring the perspectives of cardiovascular professionals toward mobilization. EM may be beneficial in the post-MI care. However, there is an evidence gap for the impact of EM post-MI in the contemporary literature. More robust evidence from randomized clinical trials is required to inform clinicians and influence practice.

Background. Critical care societies recommend early mobilization (EM) as standard practice in the intensive care unit (ICU) setting. However, there is limited randomized controlled trial (RCT) evidence supporting EM’s effectiveness. Our objective was to identify ongoing or completed RCTs assessing EM’s effectiveness in the ICU. Method. We searched ClinicalTrials.gov and the Australian New Zealand Clinical Trials Registry for ongoing or completed but not published RCTs in an ICU setting with objective outcome measures. Results. There were 14 RCTs included in the analysis. All studies were in the general or mixed ICU setting (N=14). Half of the studies (N=7) were small RCTs (

Spasticity is a common comorbidity associated with spinal cord injury (SCI). Robotic exoskeletons have recently emerged to facilitate legged mobility in people with motor complete SCI. Involuntary muscle activity attributed to spasticity, however, can prevent such individuals from using an exoskeleton. Specifically, although most exoskeleton technologies can accommodate low to moderate spasticity, the presence of moderate to severe spasticity can significantly impair gait kinematics when using an exoskeleton. In an effort to potentially enable individuals with moderate to severe spasticity to use exoskeletons more effectively, this study investigates the use of common peroneal stimulation in conjunction with exoskeleton gait assistance. The electrical stimulation is timed with the exoskeleton swing phase, and is intended to acutely suppress extensor spasticity through recruitment of the flexion withdrawal reflex (i.e., while the stimulation is activated) to enable improved exoskeletal walking. In order to examine the potential efficacy of this approach, two SCI subjects with severe extensor spasticity (i.e., modified Ashworth ratings of three to four) walked in an exoskeleton with and without supplemental stimulation while knee and hip motion was measured during swing phase. Stimulation was alternated on and off every ten steps to eliminate transient therapeutic effects, enabling the acute effects of stimulation to be isolated. These experiments indicated that common peroneal stimulation on average increased peak hip flexion during the swing phase of walking by 21.1° (236%) and peak knee flexion by 14.4° (56%). Additionally, use of the stimulation decreased the swing phase RMS motor current by 228 mA (15%) at the hip motors and 734 mA (38%) at the knee motors, indicating improved kinematics were achieved with reduced effort from the exoskeleton. Walking with the exoskeleton did not have a significant effect on modified Ashworth scores, indicating the common peroneal stimulation has only acute effects on suppressing extensor tone and aiding flexion. This preliminary data indicates that such supplemental stimulation may be used to improve the quality of movement provided by exoskeletons for persons with severe extensor spasticity in the lower limb.

Regular use of prostheses is critical for individuals with lower limb amputations to achieve everyday mobility, maintain physical and physiological health, and achieve a better quality of life. Use of prostheses is influenced by numerous factors, with prosthetic design playing a critical role in facilitating mobility for an amputee. Thus, prostheses design can either promote biomechanically efficient or inefficient gait behavior. In addition to increased energy expenditure, inefficient gait behavior can expose prosthetic user to an increased risk of secondary musculoskeletal injuries and may eventually lead to rejection of the prosthesis. Consequently, researchers have utilized the technological advancements in various fields to improve prosthetic devices and customize them for user specific needs. One evolving technology is powered prosthetic components. Presently, an active area in lower limb prosthetic research is the design of novel controllers and components in order to enable the users of such powered devices to be able to reproduce gait biomechanics that are similar in behavior to a healthy limb. In this case series, we studied the impact of using a powered knee-ankle prostheses (PKA) on two transfemoral amputees who currently use advanced microprocessor controlled knee prostheses (MPK). We utilized outcomes pertaining to kinematics, kinetics, metabolics, and functional activities of daily living to compare the efficacy between the MPK and PKA devices. Our results suggests that the PKA allows the participants to walk with gait kinematics similar to normal gait patterns observed in a healthy limb. Additionally, it was observed that use of the PKA reduced the level of asymmetry in terms of mechanical loading and muscle activation, specifically in the low back spinae regions and lower extremity muscles. Further, the PKA allowed the participants to achieve a greater range of cadence than their predicate MPK, thus allowing them to safely ambulate in variable environments and dynamically control speed changes. Based on the results of this case series, it appears that there is considerable potential for powered prosthetic components to provide safe and efficient gait for individuals with above the knee amputation.

This paper presents a formulation for selecting the stage ratios and number of stages in a multistage transmission with a given desired total transmission ratio in a manner that maximizes efficiency, maximizes acceleration, or minimizes the mass of the transmission. The formulation is used to highlight several implications for gear train design, including the fact that minimizing rotational inertia and mass are competing objectives with respect to optimal selection of stage ratios, and that both rotational inertia and mass can often be minimized by increasing the total number of stages beyond a minimum realizable number. Additionally, a multistage transmission will generally provide maximum acceleration when the stage ratios increase monotonically from the motor to the load. The transmission will have minimum mass when the stage ratios decrease monotonically. The transmission will also provide maximum efficiency when the corresponding stages employ constant stage ratios. This paper aims to use this optimization formulation to elucidate tradeoffs between various common objectives in gear train design (efficiency, acceleration, and mass).