Light-Weight Wearable Gyroscopic Actuators Can Modulate Balance Performance and Gait Characteristics: A Proof-of-Concept Study.

Falling is a major cause of morbidity, and is often caused by a decrease in postural stability. A key component of postural stability is whole-body centroidal angular momentum, which can be influenced by control moment gyroscopes. In this proof-of-concept study, we explore the influence of our wearable robotic gyroscopic actuator "GyroPack" on the balance performance and gait characteristics of non-impaired individuals (seven female/eight male, 30 ± 7 years, 68.8 ± 8.4 kg). Participants performed a series of balance and walking tasks with and without wearing the GyroPack. The device displayed various control modes, which were hypothesised to positively, negatively, or neutrally impact postural control. When configured as a damper, the GyroPack increased mediolateral standing time and walking distance, on a balance beam, and decreased trunk angular velocity variability, while walking on a treadmill. When configured as a negative damper, both peak trunk angular rate and trunk angular velocity variability increased during treadmill walking. This exploratory study shows that gyroscopic actuators can influence balance and gait kinematics. Our results mirror the findings of our earlier studies; though, with more than 50% mass reduction of the device, practical and clinical applicability now appears within reach.

Performance of a Mobile 3D Camera to Evaluate Simulated Pathological Gait in Practical Scenarios.

Three-dimensional (3D) cameras used for gait assessment obviate the need for bodily markers or sensors, making them particularly interesting for clinical applications. Due to their limited field of view, their application has predominantly focused on evaluating gait patterns within short walking distances. However, assessment of gait consistency requires testing over a longer walking distance. The aim of this study is to validate the accuracy for gait assessment of a previously developed method that determines walking spatiotemporal parameters and kinematics measured with a 3D camera mounted on a mobile robot base (ROBOGait). Walking parameters measured with this system were compared with measurements with Xsens IMUs. The experiments were performed on a non-linear corridor of approximately 50 m, resembling the environment of a conventional rehabilitation facility. Eleven individuals exhibiting normal motor function were recruited to walk and to simulate gait patterns representative of common neurological conditions: Cerebral Palsy, Multiple Sclerosis, and Cerebellar Ataxia. Generalized estimating equations were used to determine statistical differences between the measurement systems and between walking conditions. When comparing walking parameters between paired measures of the systems, significant differences were found for eight out of 18 descriptors: range of motion (ROM) of trunk and pelvis tilt, maximum knee flexion in loading response, knee position at toe-off, stride length, step time, cadence; and stance duration. When analyzing how ROBOGait can distinguish simulated pathological gait from physiological gait, a mean accuracy of 70.4%, a sensitivity of 49.3%, and a specificity of 74.4% were found when compared with the Xsens system. The most important gait abnormalities related to the clinical conditions were successfully detected by ROBOGait. The descriptors that best distinguished simulated pathological walking from normal walking in both systems were step width and stride length. This study underscores the promising potential of 3D cameras and encourages exploring their use in clinical gait analysis.

Quantification of the development of trunk control in healthy infants using inertial measurement units.

Trunk motor control is essential for the proper functioning of the upper extremities and is an important predictor of gait capacity in children with delayed development. Early diagnosis and intervention could increase the trunk motor capabilities in later life, but current tools used to assess the level of trunk motor control are largely subjective and many lack the sensitivity to accurately monitor development and the effects of therapy. Inertial measurement units could yield an objective quantitative assessment that is inexpensive and easy-to-implement. We hypothesized that root mean square of jerk, a proxy for movement smoothness, could be used to distinguish age and thereby presumed motor development. We attached a sensor to the trunks of six young children with no known developmental deficits. Root mean square of jerk decreases with age, up to 24 months, and is correlated to a more established method, i.e., center-of-pressure velocity, as well as other standard inertial measurement unit outputs. This metric therefore shows potential as a method to differentiate trunk motor control levels.

Controller synthesis and clinical exploration of wearable gyroscopic actuators to support human balance.

Gyroscopic actuators are appealing for wearable applications due to their ability to provide overground balance support without obstructing the legs. Multiple wearable robots using this actuation principle have been proposed, but none has yet been evaluated with humans. Here we use the GyBAR, a backpack-like prototype portable robot, to investigate the hypothesis that the balance of both healthy and chronic stroke subjects can be augmented through moments applied to the upper body. We quantified balance performance in terms of each participant's ability to walk or remain standing on a narrow support surface oriented to challenge stability in either the frontal or the sagittal plane. By comparing candidate balance controllers, it was found that effective assistance did not require regulation to a reference posture. A rotational viscous field increased the distance healthy participants could walk along a 30mm-wide beam by a factor of 2.0, compared to when the GyBAR was worn but inactive. The same controller enabled individuals with chronic stroke to remain standing for a factor of 2.5 longer on a narrow block. Due to its wearability and versatility of control, the GyBAR could enable new therapy interventions for training and rehabilitation.

Biarticular muscles are most responsive to upper-body pitch perturbations in human standing.

Balancing the upper body is pivotal for upright and efficient gait. While models have identified potentially useful characteristics of biarticular thigh muscles for postural control of the upper body, experimental evidence for their specific role is lacking. Based on theoretical findings, we hypothesised that biarticular muscle activity would increase strongly in response to upper-body perturbations. To test this hypothesis, we used a novel Angular Momentum Perturbator (AMP) that, in contrast to existing methods, perturbs the upper-body posture with only minimal effect on Centre of Mass (CoM) excursions. The impulse-like AMP torques applied to the trunk of subjects resulted in upper-body pitch deflections of up to 17° with only small CoM excursions below 2 cm. Biarticular thigh muscles (biceps femoris long head and rectus femoris) showed the strongest increase in muscular activity (mid- and long-latency reflexes, starting 100 ms after perturbation onset) of all eight measured leg muscles which highlights the importance of biarticular muscles for restoring upper-body balance. These insights could be used for improving technological aids like rehabilitation or assistive devices, and the effectiveness of physical training for fall prevention e.g. for elderly people.

Resultados clínicos de injertos óseos autólogos en bloque / Clinical results of autologous bone block grafts

Introducción: En muchas ocasiones, el sitio edéntulo del paciente no cuenta con el sufi ciente volumen óseo para albergar un implante. El injerto óseo autólogo en bloque (IOAB) es una opción para acondicionar al individuo y poder realizar la colocación del implante. Objetivo: Determinar el porcentaje de éxito y fracaso de los IOAB y sus factores relacionados...

Introduction: Very often, there is insufficient bone volume available in the edentulous site of a patient to allow dental implant placement. One way to prepare such patients for an implant placement is to usean autologous bone block (ABB) graft. Objective: To determine the success and failure rates of ABB grafts and their associated factors...

[Distribution patterns of wild felids (Carnivora: Felidae) in the dry tropics of Central-Western Mexico]. / Patrones de distribución de felinos silvestres (Carnivora: Felidae) en el trópico seco del Centro-Occidente de México.

The Michoacán state is characterized by the existence of important environmental heterogeneity in terms of climate, topography and types of vegetation, which includes the worldwide endangered tropical dry forest. Some reports indicating the presence of the six species of felids occurring in Mexico in this region have been made; however, evidence to support these reports is scant, and filling this lack of information is particularly critical in the case of threatened species or habitats. The aim of this study was to systematize and analyze data distribution patterns of felids in the state of Michoacán, in the Central-Western Mexico. We conducted a review of literature and databases to compile species presence records in the study region. Moreover, we analyzed data obtained from ten years of field work conducted in the region, in which complementary methods (detection of direct and indirect evidence of species occurrence along transects, camera-trapping and interviews to local people) were applied to detect the presence of felid species. We compiled a total of 29 presence records of felids in the region from our review. Additionally, field work, which accumulated 1,107.5 km of walked transects, and 8 699 camera-trap days, produced 672 records of species presence. Lynx rufus was the species with the lowest number of records and the most restricted distribution. In contrast, the species with the greatest number of records was Leoparduspardalis (n = 343). In general, 89% of felids records occurred below 1,000 masl. Overall mean annual temperature of presence records was 24 °C and mean annual precipitation was 1,040 mm. The species whose presence records showed the most distinctive pattern, in terms of temperature and precipitation associated, was L. rufus (15.8 ± 1.3°C and 941 ± 171 mm). Results of a cluster analysis showed that areas supporting different combinations of eco-regions and types of vegetation could be grouped in five clusters having different assemblages of felid species and camera-trapping records. This study results useful to garner a more comprehensive view of the distribution patterns of felids in a region with important environmental contrasts and subjected to an increased human pressure. Moreover, this study provides insights that further our understanding of the relationship between environmental variables and felid distribution patterns which may have an impact for conservation and management strategies at the local and regional levels.

Patrones de distribución de felinos silvestres (Carnívora: Felidae) en el trópico seco del Centro-Occidente de México / Distribution patterns of wild felids (Carnivora: Felidae) in the dry tropics of Central-Western Mexico

El estado de Michoacán se caracteriza por presentar una importante heterogeneidad ambiental, en términos de clima, topografía y tipos de vegetación, que incluyen al bosque tropical seco que se encuentra en peligro de extinción a nivel mundial. Algunos trabajos mencionan la presencia de las seis especies de felinos que habitan en México, para la región; sin embargo, la evidencia para apoyar estos trabajos es escasa, por lo que llenar esta falta de información es especialmente crítico en el caso de especies o hábitats amenazados. El objetivo de este estudio fue sistematizar la información y analizar los patrones de distribución de los felinos en el estado de Michoacán, dentro del centro-occidente de México. Realizamos una revisión de la información bibliográfica y contenida en bases de datos sobre la presencia de felinos en esta región. Asimismo, realizamos trabajo de campo que en el curso de diez años donde se aplicaron distintos métodos para detectar la presencia de especies de felinos (recorrido de senderos para obtener evidencia directa e indirecta de la presencia de las especies, trampas cámara y entrevistas). Localizamos 29 registros de presencia en literatura y bases de datos. Por otra parte acumulamos un total de 1 107.5 km de transectos recorridos y 8 699 días/cámara-trampa. A través de este esfuerzo de muestreo, generamos 672 registros de presencia de las seis especies. Lynx rufusfue la especie con menos registros totales (n = 3) y cuya distribución contrastó más con la del resto de las especies. La especie con más registros fue Leopardus pardalis(n = 343). En general, el 89% de los registros de felinos se obtuvieron por debajo de los 1 000 msnm. En promedio, la temperatura media anual y la precipitación anual donde se ubicaron los registros fue de 24 °C y 1 040 mm respectivamente. La especie que mostro un patrón más claro en términos de temperatura y precipitación fue L. rufus(15.8 ± 1.3°C y 941 ± 171 mm). De acuerdo con el dendrograma resultante del análisis de conglomerados de las combinaciones de ecorregiones y tipos de vegetación se logró distinguir cinco grupos. Este estudio permite tener un panorama más completo de los patrones de distribución de los felinos en una región de importante contraste ambiental y sujeto a un fuerte impacto por las actividades humanas. Asimismo, los datos generados en este estudio pueden ayudar a profundizar nuestro entendimiento de la relación que existe entre la distribución de especies de felinos y las características del ambiente y servir como base para el desarrollo de estrategias de conservación local y regional.

The Michoacán state is characterized by the existence of important environmental heterogeneity in terms of climate, topography and types of vegetation, which includes the worldwide endangered tropical dry forest. Some reports indicating the presence of the six species of felids occurring in Mexico in this region have been made; however, evidence to support these reports is scant, and filling this lack of information is particularly critical in the case of threatened species or habitats. The aim of this study was to systematize and analyze data distribution patterns of felids in the state of Michoacán, in the Central-Western Mexico. We conducted a review of literature and databases to compile species presence records in the study region. Moreover, we analyzed data obtained from ten years of field work conducted in the region, in which complementary methods (detection of direct and indirect evidence of species occurrence along transects, camera-trapping and interviews to local people) were applied to detect the presence of felid species. We compiled a total of 29 presence records of felids in the region from our review. Additionally, field work, which accumulated 1 107.5 km of walked transects, and 8 699 camera-trap days, produced 672 records of species presence. Lynx rufuswas the species with the lowest number of records and the most restricted distribution. In contrast, the species with the greatest number of records was Leopardus pardalis(n = 343). In general, 89% of felids records occurred below 1 000 masl. Overall mean annual temperature of presence records was 24 °C and mean annual precipitation was 1 040 mm. The species whose presence records showed the most distinctive pattern, in terms of temperature and precipitation associated, was L. rufus(15.8 ± 1.3°C and 941 ± 171 mm). Results of a cluster analysis showed that areas supporting different combinations of eco-regions and types of vegetation could be grouped in five clusters having different assemblages of felid species and camera-trapping records. This study results useful to garner a more comprehensive view of the distribution patterns of felids in a region with important environmental contrasts and subjected to an increased human pressure. Moreover, this study provides insights that further our understanding of the relationship between environmental variables and felid distribution patterns which may have an impact for conservation and management strategies at the local and regional levels.