Development of a Muscle Force Optimization Algorithm to Improve Center of Pressure During Simulated Walking

The Universal Musculoskeletal Simulator (UMS) was developed at the Cleveland Clinic to facilitate general purpose orthopaedic research that allows investigators to study the in vitro forces applied to bones, tendons and ligaments during simulated exercise of cadaver joint systems. In its original state, the UMS hardware consisted of a rotopod (a specialized hexapod robot), a single rotary tendon actuator and custom LabVIEW software for coordinated control and operation of the system. The focus of this work was to 1) enhance the UMS with a multi-tendon actuator system, 2) develop a muscle force optimization algorithm and evaluate it with a static model of the foot/ankle, 3) integrate the algorithm with the UMS software and evaluate it with cadaver specimens, and 4) utilize the enhanced UMS to investigate the individual muscle contributions to center of pressure using cadaver specimens. Completion of the multi-tendon actuator system has enabled researchers to simulate exercise on cadaver joints by using up to five motorized actuators to simulate muscle forces that would occur during exercise while simultaneously contacting the joint with an external load generated by the rotopod. Although the multi-tendon actuator system was first conceived as a necessary enhancement to simulate the key extrinsic muscles of the ankle/foot, required to conduct simulated walking with cadaver feet, it was soon recognized that this system could be utilized to simulate muscles forces of other joints (i.e., shoulder, wrist, spine, etc.) and as such now provides a general purpose test bed for conducting orthopaedic research. Initial cadaver studies of the foot/ankle using the UMS revealed that normal physiological center of pressure patterns were difficult to achieve during simulated walking. Therefore, the primary goal of this effort was to develop an algorithm that would optimize the muscle forces to better achieve the desired medial-lateral and anterior-posterior center of pressure profiles expected during physiologically accurate si

Relationship Between Arch Height and Midfoot Joint Pressures During Gait

A foot arch is a multi-segmented curved structure which acts as a spring during locomotion. It is well known that ligaments are important components contributing to this spring-like property of the arch. In addition, intrinsic and extrinsic foot muscles contribute to arch support. According to the windlass foot model, arch height and midfoot joint orientation change during gait. However, it is not known whether altered joint configurations result in increased joint stress during gait. If so, it is possible for there to be a vicious cycle in which joint stress increases as the arch height diminishes, which may then lead to further increases in joint stresses and eventual bone destruction. The purpose of this study was to examine joint pressure differences of the midfoot in normal and diabetic feet during walking simulation using a robotic system. This study focused on the relative importance of muscles, ligaments and bony structures. Sixteen cadaver foot specimens were used in this study. Joint pressures were measured dynamically during full stance at four medial locations (the first cuneometatarsal, medial cuneonavicular, middle cuneonavicular, and first intercuneiform). Human gait at 25 typical walking speed and 66.7 body weight was simulated with the Universal Musculoskeletal Simulator. It was shown that diabetic cadaver feet had, on average, a 46 higher peak in pressures, than control cadaver feet across all four tested joints. There were inverse correlations between the arch height and the peak joint pressure during the simulated arch collapse. It was proven that the acquired flat foot, caused by the tibialis posterior dysfunction, caused medial peak joint pressure increase by 12 across all tested joints. These results could be used in furthering our understanding of the etiology of diabetic foot diseases. Also, these findings could suggest better treatment for diabetic patients, who are at risk for Charcot foot abnormalitie

Relationship Between Arch Height and Midfoot Joint Pressures During Gait

A foot arch is a multi-segmented curved structure which acts as a spring during locomotion. It is well known that ligaments are important components contributing to this spring-like property of the arch. In addition, intrinsic and extrinsic foot muscles contribute to arch support. According to the windlass foot model, arch height and midfoot joint orientation change during gait. However, it is not known whether altered joint configurations result in increased joint stress during gait. If so, it is possible for there to be a vicious cycle in which joint stress increases as the arch height diminishes, which may then lead to further increases in joint stresses and eventual bone destruction. The purpose of this study was to examine joint pressure differences of the midfoot in normal and diabetic feet during walking simulation using a robotic system. This study focused on the relative importance of muscles, ligaments and bony structures. Sixteen cadaver foot specimens were used in this study. Joint pressures were measured dynamically during full stance at four medial locations (the first cuneometatarsal, medial cuneonavicular, middle cuneonavicular, and first intercuneiform). Human gait at 25 typical walking speed and 66.7 body weight was simulated with the Universal Musculoskeletal Simulator. It was shown that diabetic cadaver feet had, on average, a 46 higher peak in pressures, than control cadaver feet across all four tested joints. There were inverse correlations between the arch height and the peak joint pressure during the simulated arch collapse. It was proven that the acquired flat foot, caused by the tibialis posterior dysfunction, caused medial peak joint pressure increase by 12 across all tested joints. These results could be used in furthering our understanding of the etiology of diabetic foot diseases. Also, these findings could suggest better treatment for diabetic patients, who are at risk for Charcot foot abnormalitie

IQ Classification via Brainwave Features: Review on Artificial Intelligence Techniques

Intelligence study is one of keystone to distinguish individual differences in cognitive psychology. Conventional psychometric tests are limited in terms of assessment time, and existence of biasness issues. Apart from that, there is still lack in knowledge to classify IQ based on EEG signals and intelligent signal processing (ISP) technique. ISP purpose is to extract as much information as possible from signal and noise data using learning and/or other smart techniques. Therefore, as a first attempt in classifying IQ feature via scientific approach, it is important to identify a relevant technique with prominent paradigm that is suitable for this area of application. Thus, this article reviews several ISP approaches to provide consolidated source of information. This in particular focuses on prominent paradigm that suitable for pattern classification in biomedical area. The review leads to selection of ANN since it has been widely implemented for pattern classification in biomedical engineering

Development of a feedback-controlled elbow simulator: design validation and clinical application

This work involves three topics that advance the functionality of an elbow simulator in the Orthopaedic Biomechanics Laboratory at Allegheny General Hospital. To draw clinically and scientifically meaningful conclusions from future cadaver studies conducted with the simulator, its design must be validated and the accuracy of the data collection methods demonstrated. The simulator was designed to offer physiologically-correct adjustable moment arms throughout the elbow's range of motion. To validate this, muscle moment arms were measured in three cadaver elbow specimens. Flexion-extension moment arms were measured at three different pronation/supination angles: fully pronated, fully supinated, and neutral. Pronation-supination moment arms for four elbow muscles were measured at three different flexion-extension angles: 30°, 60°, and 90°. The numeric results compared well with those previously reported. The biceps and pronator teres flexion-extension moment arms varied with pronation-supination position, and vice versa. This represents the first use of closed-loop feedback control in an elbow simulator, one of the first reports of both flexion-extension and pronation-supination moment arms in the same specimens, and demonstrates the adjustability of the moment arms that the elbow simulator can produce.Towards accurate motion analysis of the radial head, two areas were investigated. The first identified the phenomena of camera-switching, which occurs in motion analysis when data from one or more cameras is temporarily excluded from the computation of a marker's three-dimensional position. Tests with static markers showed that camera-switching could cause up to 3.7 mm of perceived movement. The second area of investigation set the stage for future studies with cadaver elbows. A protocol was developed to quantify both the travel of the native radial head, radial head implants, and the finite helical axis during pronation-supination movement. The tracking of implant motion employs a unique circle-fitting algorithm to determine the implant's center. A video-based motion analysis system was used to collect marker position coordinates actuated by a precision micrometer table. MATLAB code was designed and implemented to compute both the radial head position and finite helical axis from these data. Immediate future work will use these algorithms to evaluate radial head implants in comparison to the native radial head

Advanced Applications of Rapid Prototyping Technology in Modern Engineering

Rapid prototyping (RP) technology has been widely known and appreciated due to its flexible and customized manufacturing capabilities. The widely studied RP techniques include stereolithography apparatus (SLA), selective laser sintering (SLS), three-dimensional printing (3DP), fused deposition modeling (FDM), 3D plotting, solid ground curing (SGC), multiphase jet solidification (MJS), laminated object manufacturing (LOM). Different techniques are associated with different materials and/or processing principles and thus are devoted to specific applications. RP technology has no longer been only for prototype building rather has been extended for real industrial manufacturing solutions. Today, the RP technology has contributed to almost all engineering areas that include mechanical, materials, industrial, aerospace, electrical and most recently biomedical engineering. This book aims to present the advanced development of RP technologies in various engineering areas as the solutions to the real world engineering problems

Applying safe flooring in housing environments related to the independent elderly : evaluating suitability flooring technology to absorb impact in the event of a fall

Aplicat embargament des de la data de defensa fins el dia 3/6/2022This research has been developed with the intention of investigating a different generation of pavements. Most of the current pavements have the same basic standard characteristics and this ensures that living conditions are comfortable, safe, and pleasant for the majority of citizens. But a small group of pavements is designed with a specific purpose: to reduce injuries related to people's falls to the ground; They are called CF (compliant flooring in English). A detailed study of CF flooring systems is warranted to assess their usability for vulnerable groups such as the elderly. This study is structured in six chapters. The first chapter has dealt mainly with bibliographic studies and statistical data consulted on official and international websites. This section evaluates the importance of the increase in the elderly population, life expectancy, and threats to the safety and health of the elderly, especially, and their secondary effects. The scope of the research has been carried out internationally, in Europe and within Spain, and finally, specifically for Catalonia. The second chapter presents a brief overview of the interior flooring, specifically considering its comfort and safety during use. The importance and direct relationship between the sole of the foot and the gait mechanism with respect to the type of pavement have been verified. Many factors that influence this have been investigated, such as the physics and biomechanics of the body when walking, the kinematics of falls, and the dynamics of impact. In addition, a general description of the behavior of materials for use in pavements has been made to better understand the behavior of CF systems. In addition, the most suitable strategies to cope with falls and reduce injuries are discussed. Examining other products with appreciable energy-absorbing and shock-reducing capabilities has been helpful in the proposed pre-designs, all of which have been made based on numerical analysis and related standards. The third chapter is already dedicated to the study of technology and research on the most suitable CF systems; studies from academic, commercial, and architecture departments, in general, are included. In this section, some standard tests related to the various selected materials are developed and several examples of similar products are studied. The fourth chapter includes field research (on-site) and analysis of case studies. Several notable flooring companies around the world were contacted by mail, specifically examining those products whose manufacturers claimed to be shock absorbers. This part of the investigation was slowed down by the delay in shipments. Once they arrived, a real environment was sought where they could obtain the opinion of the elderly and the personnel assigned to their care. All the practice tests were carried out in a residence for the elderly in Barcelona for about two months, focusing on the study of the current pavements of the center and the current derived problems related to users.This entire process was completed by interviewing users and caregivers with predefined questionnaires. It should be noted that this allowed us to contrast the quantitative characteristics of the study in combination with the elements of qualitative research. Chapter Five deals with the results, discussions, suggestions for installation and improvement of pavement safety in risk areas. Simulations were also carried out on a possible base structure of the pavements with the finite element method (FEM). Chapter six presents guidelines for future developments. The author further investigated the materials and their structure and is presented them as a basis for future technical developments.The author considers that, with more detailed studies, it would be possible to use as CF system other materials, either natural or recycled based on agricultural products, which would increase the diversity of the CF system offer and promote more sustainable architectureEsta investigación se ha desarrollado con la intención de investigar una generación diferente de pavimentos. La mayoría de los actuales pavimentos tienen las mismas características básicas estándar y ello garantiza que las condiciones de vida sean cómodas, seguras y agradables para la mayoría de los ciudadanos. Pero un grupo reducido de pavimentos está diseñado con un propósito específico: reducir las lesiones relacionadas con las caídas al suelo de las personas; son los denominados CF (compliant flooring en inglés). Un estudio detallado de los sistemas de pavimentos CF está justificado para evaluar su posibilidad de uso para grupos vulnerables como los ancianos. Este estudio se estructura en seis capítulos. En el primer capítulo se han abordado principalmente los estudios bibliográficos y datos estadísticos consultados en sitios web oficiales e internacionales. En esta sección se evalúa la importancia del aumento de la población anciana. El ámbito de la investigación se ha realizado a nivel internacional, en Europa y dentro de España, y finalmente, específicamente para Cataluña. El segundo capítulo se presenta una breve panorámica del pavimento interior. Se ha constatado la importancia y relación directa entre la planta del pie y el mecanismo de andar con respecto al tipo de pavimento. Se han investigado muchos factores que influyen en ello. Además, se ha realizado una descripción general del comportamiento de los materiales al uso en pavimentos para comprender mejor el comportamiento de los sistemas de CF. Además, se discuten las estrategias más idóneas para hacer frente a las caídas y reducir las lesiones. Examinar otros productos con apreciables capacidades de amortiguación de energía y reducción de impactos ha sido de gran ayuda en los prediseños propuestos, todos los cuales se han realizado sobre la base de análisis numérico y los estándares relacionados. El tercer capítulo está dedicado ya al estudio de la tecnología y la investigación sobre los sistemas de C más idóneos; se incluyen estudios procedentes de departamentos académicos, comerciales y de arquitectura en general. En esta sección se desarrollan algunas pruebas estándar relacionadas con los diversos materiales seleccionados y se estudian varios ejemplos de productos similares. El cuarto capítulo incluye investigación de campo (in situ) y análisis de estudios de casos. Se contactó por correo con varias empresas notables de pavimentos en todo el mundo, y se examinaron específicamente aquellos productos cuyos fabricantes afirmaban ser amortiguadores. Esta parte de la investigación se vio ralentizada por la demora en los envíos. Una vez llegados se buscó un ámbito real donde poder recabar la opinión de las personas mayores y del personal adscrito a su cuidado. Todas las pruebas prácticas se realizaron en una residencia de ancianos de Barcelona durante unos dos meses, centrándose en el estudio de los actuales pavimentos del centro y los problemas actuales derivados relacionados con los usuarios. Todo este proceso se completó mediante entrevistas a usuarios y cuidadores con cuestionarios predefinidos. El Capítulo Cinco se refiere a los resultados, discusiones, sugerencias para la instalación y mejora de la seguridad del pavimento en áreas de riesgo. También se realizaron simulaciones sobre una posible estructura base de los pavimentos con el método elemento finito (FEM). El capítulo seis presenta directrices para desarrollos futuros. El autor investigó más a fondo sobre los materiales y su estructura, y se presenta como una base para desarrollos técnicos futuros. El autor considera que, con estudios más detallados, sería posible utilizar como CF otros materiales, bien naturales o reciclados a base de productos agrícolas, lo cual aumentaría la diversidad de la oferta de CF y fomentaría la arquitectura más sostenible.Postprint (published version