Stiffness Parameter Identification of the Muscles of Mastication

Oral cancer survivors across the country live with a condition called trismus, or spasm of the jaw muscles, that restricts their ability to perform basic functions such as eating and talking. In order to relieve these patients of their symptoms, we propose a novel wearable device with the capability to adjust to the complete 6 degree of freedom movement of the jaw to perform therapeutic exercises and run real-time diagnostics. These diagnostic can identify certain stiffness parameters that define a patients capabilities of each portion of the 3 closing muscles pairs. Two approaches were implemented i) physician input trajectory and ii) physician input forcing function. For the input trajectory method, a linear least squares approach and a nonlinear least approach were attempted. An extended kalman filter approach was utilized for the force input method. The results concluded each method is feasible but both depend on the accuracy of the model and initial estimate. The degree of mouth opening dictated the amount of information regarding certain stiffness parameters and dictated the success of each approach. This lays the groundwork for an experimental approach to validate the relevance of certain stiffness parameters in the clinic

Impact of Ear Occlusion on In-Ear Sounds Generated by Intra-oral Behaviors

We conducted a case study with one volunteer and a recording setup to detect sounds induced by the actions: jaw clenching, tooth grinding, reading, eating, and drinking. The setup consisted of two in-ear microphones, where the left ear was semi-occluded with a commercially available earpiece and the right ear was occluded with a mouldable silicon ear piece. Investigations in the time and frequency domains demonstrated that for behaviors such as eating, tooth grinding, and reading, sounds could be recorded with both sensors. For jaw clenching, however, occluding the ear with a mouldable piece was necessary to enable its detection. This can be attributed to the fact that the mouldable ear piece sealed the ear canal and isolated it from the environment, resulting in a detectable change in pressure. In conclusion, our work suggests that detecting behaviors such as eating, grinding, reading with a semi-occluded ear is possible, whereas, behaviors such as clenching require the complete occlusion of the ear if the activity should be easily detectable. Nevertheless, the latter approach may limit real-world applicability because it hinders the hearing capabilities.</p

Applications of EMG in Clinical and Sports Medicine

This second of two volumes on EMG (Electromyography) covers a wide range of clinical applications, as a complement to the methods discussed in volume 1. Topics range from gait and vibration analysis, through posture and falls prevention, to biofeedback in the treatment of neurologic swallowing impairment. The volume includes sections on back care, sports and performance medicine, gynecology/urology and orofacial function. Authors describe the procedures for their experimental studies with detailed and clear illustrations and references to the literature. The limitations of SEMG measures and methods for careful analysis are discussed. This broad compilation of articles discussing the use of EMG in both clinical and research applications demonstrates the utility of the method as a tool in a wide variety of disciplines and clinical fields

Stiffness Parameter Identification of the Muscles of Mastication

Oral cancer survivors across the country live with a condition called trismus, or spasm of the jaw muscles, that restricts their ability to perform basic functions such as eating and talking. In order to relieve these patients of their symptoms, we propose a novel wearable device with the capability to adjust to the complete 6 degree of freedom movement of the jaw to perform therapeutic exercises and run real-time diagnostics. These diagnostic can identify certain stiffness parameters that define a patients capabilities of each portion of the 3 closing muscles pairs. Two approaches were implemented i) physician input trajectory and ii) physician input forcing function. For the input trajectory method, a linear least squares approach and a nonlinear least approach were attempted. An extended kalman filter approach was utilized for the force input method. The results concluded each method is feasible but both depend on the accuracy of the model and initial estimate. The degree of mouth opening dictated the amount of information regarding certain stiffness parameters and dictated the success of each approach. This lays the groundwork for an experimental approach to validate the relevance of certain stiffness parameters in the clinic

Book of Abstracts 15th International Symposium on Computer Methods in Biomechanics and Biomedical Engineering and 3rd Conference on Imaging and Visualization

In this edition, the two events will run together as a single conference, highlighting the strong connection with the Taylor & Francis journals: Computer Methods in Biomechanics and Biomedical Engineering (John Middleton and Christopher Jacobs, Eds.) and Computer Methods in Biomechanics and Biomedical Engineering: Imaging and Visualization (JoãoManuel R.S. Tavares, Ed.). The conference has become a major international meeting on computational biomechanics, imaging andvisualization. In this edition, the main program includes 212 presentations. In addition, sixteen renowned researchers will give plenary keynotes, addressing current challenges in computational biomechanics and biomedical imaging. In Lisbon, for the first time, a session dedicated to award the winner of the Best Paper in CMBBE Journal will take place. We believe that CMBBE2018 will have a strong impact on the development of computational biomechanics and biomedical imaging and visualization, identifying emerging areas of research and promoting the collaboration and networking between participants. This impact is evidenced through the well-known research groups, commercial companies and scientific organizations, who continue to support and sponsor the CMBBE meeting series. In fact, the conference is enriched with five workshops on specific scientific topics and commercial software.info:eu-repo/semantics/draf

Síntesis de mecanismos con algoritmos evolutivos para aplicaciones médicas

El objeto de la Tesis es la aplicación de técnicas de síntesis de mecanismos al diseño de dispositivos médicos, destinados a mover de forma controlada alguna parte del cuerpo, con el fin de poder fabricar dispositivos personalizados para cada paciente. A lo largo del trabajo se presenta una metodología genérica que puede ser aplicada para el diseño y fabricación de estos dispositivos. Se han realizado tres aplicaciones prácticas de la metodología propuesta. Se ha diseñado un exoesqueleto para la rehabilitación de un dedo de la mano, un exoesqueleto para mover todos los dedos de la mano a excepción del pulgar y un dispositivo de avance mandibular para el tratamiento de la apnea del sueño. La personalización de los exoesqueletos permite simplificarlos y abaratarlos, mientras que la personalización de los dispositivos para el tratamiento de la apnea del sueño teniendo en cuenta el comportamiento cinemático de la mandíbula del paciente, aumenta la efectividad del tratamiento. El diseño de los dispositivos empieza con un estudio cinemático de la parte del cuerpo afectada para poder desarrollar un modelo cinemático de la misma y definir los datos necesarios para resolver el problema. Se le da especial relevancia al hecho de que los datos sean sencillos de obtener. En general, la mejor opción es poder medir las distancias y ángulos necesarios en una radiografía o un escáner. En el caso de los exoesqueletos, es necesario realizar además un vídeo del movimiento del paciente para medir, en distintos fotogramas, las posiciones deseadas a lo largo de un ciclo. Una vez desarrollado el modelo cinemático, el siguiente paso es definir un problema de optimización. La solución de este problema será un sistema mecánico adaptado a las características del paciente. Para su resolución se utiliza el algoritmo evolutivo MUMSA, cuyo funcionamiento se explica en la Tesis

Analysis of forearm muscles activity by means of new protocols of multichannel EMG signal recording and processing

Los movimientos voluntarios del cuerpo son controlados por el sistema nervioso central y periférico a través de la contracción de los músculos esqueléticos. La contracción se inicia al liberarse un neurotransmisor sobre la unión neuromuscular, iniciando la propagación de un biopotencial sobre la membrana de las fibras musculares que se desplaza hacia los tendones: el Potencial de Acción de la Unidad Motora (MUAP). La señal electromiográfica de superficie registra la activación continua de dichos potenciales sobre la superficie de la piel y constituye una valiosa herramienta para la investigación, diagnóstico y seguimiento clínico de trastornos musculares, así como para la identificación de la intención movimiento tanto en términos de dirección como de potencia. En el estudio de las enfermedades del sistema neuromuscular es necesario analizar el nivel de actividad, la capacidad de producción de fuerza, la activación muscular conjunta y la predisposición a la fatiga muscular, todos ellos asociados con factores fisiológicos que determinan la resultante contracción mioeléctrica. Además, el uso de matrices de electrodos facilita la investigación de las propiedades periféricas de las unidades motoras activas, las características anatómicas del músculo y los cambios espaciales en su activación, ocasionados por el tipo de tarea motora o la potencia de la misma. El objetivo principal de esta tesis es el diseño e implementación de protocolos experimentales y algoritmos de procesado para extraer información fiable de señales sEMG multicanal en 1 y 2 dimensiones del espacio. Dicha información ha sido interpretada y relacionada con dos patologías específicas de la extremidad superior: Epicondilitis Lateral y Lesión de Esfuerzo Repetitivo. También fue utilizada para identificar la dirección de movimiento y la fuerza asociada a la contracción muscular, cuyos patrones podrían ser de utilidad en aplicaciones donde la señal electromiográfica se utilice para controlar interfaces hombre-máquina como es el caso de terapia física basada en robots, entornos virtuales de rehabilitación o realimentación de la actividad muscular. En resumen, las aportaciones más relevantes de esta tesis son: * La definición de protocolos experimentales orientados al registro de señales sEMG en una región óptima del músculo. * Definición de índices asociados a la co-activación de diferentes músculos * Identificación de señales artefactuadas en registros multicanal * Selección de los canales mas relevantes para el análisis Extracción de un conjunto de características que permita una alta exactitud en la identificación de tareas motoras Los protocolos experimentales y los índices propuestos permitieron establecer que diversos desequilibrios entre músculos extrínsecos del antebrazo podrían desempeñar un papel clave en la fisiopatología de la epicondilitis lateral. Los resultados fueron consistentes en diferentes ejercicios y pueden definir un marco de evaluación para el seguimiento y evaluación de pacientes en programas de rehabilitación motora. Por otra parte, se encontró que las características asociadas con la distribución espacial de los MUAPs mejoran la exactitud en la identificación de la intención de movimiento. Lo que es más, las características extraídas de registros sEMG de alta densidad son más robustas que las extraídas de señales bipolares simples, no sólo por la redundancia de contacto implicada en HD-EMG, sino también porque permite monitorizar las regiones del músculo donde la amplitud de la señal es máxima y que varían con el tipo de ejercicio, permitiendo así una mejor estimación de la activación muscular mediante el análisis de los canales mas relevantes.Voluntary movements are achieved by the contraction of skeletal muscles controlled by the Central and Peripheral Nervous system. The contraction is initiated by the release of a neurotransmitter that promotes a reaction in the walls of the muscular fiber, producing a biopotential known as Motor Unit Action Potential (MUAP) that travels from the neuromuscular junction to the tendons. The surface electromyographic signal records the continuous activation of such potentials over the surface of the skin and constitutes a valuable tool for the diagnosis, monitoring and clinical research of muscular disorders as well as to infer motion intention not only regarding the direction of the movement but also its power. In the study of diseases of the neuromuscular system it is necessary to analyze the level of activity, the capacity of production of strength, the load-sharing between muscles and the probably predisposition to muscular fatigue, all of them associated with physiological factors determining the resultant muscular contraction. Moreover, the use of electrode arrays facilitate the investigation of the peripheral properties of the active Motor Units, the anatomical characteristics of the muscle and the spatial changes induced in their activation of as product of type of movement or power of the contraction.The main objective of this thesis was the design and implementation of experimental protocols, and algorithms to extract information from multichannel sEMG signals in 1 and 2 dimensions of the space. Such information was interpreted and related to pathological events associated to two upper-limb conditions: Lateral Epicondylitis and Repetitive Strain Injury. It was also used to identify the direction of movement and contraction strength which could be useful in applications concerning the use of biofeedback from EMG like in robotic- aided therapies and computer-based rehabilitation training.In summary, the most relevant contributions are:§The definition of experimental protocols intended to find optimal regions for the recording of sEMG signals. §The definition of indices associated to the co- activation of different muscles. §The detection of low-quality signals in multichannel sEMG recordings.§ The selection of the most relevant EMG channels for the analysis§The extraction of a set of features that led to high classification accuracy in the identification of tasks.The experimental protocols and the proposed indices allowed establishing that imbalances between extrinsic muscles of the forearm could play a key role in the pathophysiology of lateral epicondylalgia. Results were consistent in different types of motor task and may define an assessment framework for the monitoring and evaluation of patients during rehabilitation programs.On the other hand, it was found that features associated with the spatial distribution of the MUAPs improve the accuracy of the identification of motion intention. What is more, features extracted from high density EMG recordings are more robust not only because it implies contact redundancy but also because it allows the tracking of (task changing) skin surface areas where EMG amplitude is maximal and a better estimation of muscle activity by the proper selection of the most significant channels

An Assessment of the Neurovascular Structures of the Trigeminal Nerve and Their Relationship to Diet in Primates

The inferior alveolar nerve (IAN) enters the mandible via the mental foramen, supplies nervous sensation to the mandibular teeth as it travels through the mandibular canal, and exits the mandibular foramen to send information to the brain to maintain chewing cycles and protect the teeth from damage. Although bony canals and foramina have been shown to form around soft-tissue structures, there are some examples (e.g., the hypoglossal nerve/canal) where the nervous structures do not comprise most of the canal/foramina space. It is important to know the size of nerves because it has been established that larger nerves convey more information at faster rates. However, no previous work has established the size of the IAN in primates or if the mandibular canal and associated foramina can be used as proxies for the nervous tissues. The purpose of this dissertation is to assess the variation seen in the IAN in using both a hard-tissue dataset comprised of tooth and mandibular canal measurements and a soft-tissue dataset comprised of the cross-sectional area (CSA) and volumetric measurements of the IAN. These two datasets explore the relationship between the IAN and the roots and enamel surfaces of I1, C1, P4, and M1, the CSA and volume of the mandibular canal, and the dietary categories of primates. Overall, the IAN is related to the bony structures of the mandible by size across primates. There were significant relationships between the tooth surface areas and the IAN throughout the mandible, with most showing either isometric or negatively allometric relationships. Additionally, the nerve CSA measurements at the mental foramen, mandibular foramen, beneath P4, beneath M1, and overall canal volumes showed significant relationships with the corresponding IAN measurements. However, while these relationships may be significant there is no evidence to support the hypothesis that the IAN fills most of the mandibular canal. Teeth are under strong selective pressure to change shape in response to a change in environment or diet in primate species. Therefore, it was hypothesized that the nervous tissues – because of their direct relationship to the teeth by supplying somatic sensation – would be under these same selective pressures. However, there was only one significant relationship found between the shape of the premolar tooth and the nervous tissue variables, with no other teeth showing significant relationships with the shape of the tooth’s surface. These relationships were further supported when there were no significant relationships between the IAN and dietary categories – reinforcing the conclusion that there are little to no differences in IAN size across primates based on diet. All cranial nerves in mammals are highly conserved in their shape, pathways, and functions, indicating strong selective pressures to maintain these nerves for their vital functions. These data showed that the IAN – a termination of cranial nerve V – is highly constrained across primates (and some mammal species) and is more likely related to the overall size of the mandible rather than selective pressures such as diet

The Application of Melatonin and Platelet-Rich Plasma in the Development of a Bioactive Calcium Aluminate Bone Regenerative Scaffold

Over 500,000 bone graft procedures are conducted annually within the United States. Autografts contribute to donor site complications and disease transmission with allografts has been described. Many ceramics are only osteoconductive and are brittle, limiting their clinical use. Thus, the objective of this study was to create a bone substitute with osteoinductive properties similar to natural bone using the ceramic biomaterial calcium aluminate (CA). Calcium aluminate materials are durable and remain moldable for an extended period of time at room temperature. Further, the surfaces of CA scaffolds can be modified with biological agents through simple chemical means to locally deliver agents directly to sites of injury. In order to enhance local bone regenerating characteristics of CA scaffolds, melatonin and platelet-rich plasma (PRP) were utilized for their known osteoinductive properties. Platelet-rich plasma enhances soft and hard tissue formation primarily through growth factor-mediated signaling pathways. Melatonin augments osteoblast differentiation and inhibits osteoclast-mediated bone resorption through receptor-dependent signaling and free radical scavenging activity, respectively. Thus, it was hypothesized that melatonin and/or PRP would provide osteoinductive properties to CA scaffolds to promote bone regeneration in a rodent model of critical-size calvaria defects. Modified CA scaffolds (CA-Mel) were produced by immobilizing melatonin to the CA surface through a covalent linkage. The biocompatibility of unmodified and modified CA scaffolds was initially tested in vitro and indicated that modified surfaces had a preference for the adhesion and proliferation of normal human osteoblasts versus NIH 3T3 fibroblasts. Moreover, the immobilization of melatonin to the CA surface may delay the differentiation of human adult mesenchymal stem cells (hAMSCs) and may have facilitated their migration across the CA surface. Two-month-old ovariectomized rats were randomized into implant groups receiving unmodified or modified scaffolds in the absence (CA and CA-Mel) or presence of PRP (CA+PRP and CA-Mel+PRP). Histological sections confirmed that both CA scaffold types were well-tolerated and provided evidence of tissue infiltration and scaffold biodegradation over time. Bone regeneration in animals was assessed by fluorochrome labeling at three and six months. While there was a lack of synergism between melatonin and PRP in the CA-Mel+PRP group, animals implanted with CA-Mel showed the greatest intensity and abundance of bone remodeling at both time points compared to all other groups. Radiographic data indicated a significant increase in the density of newly formed bone over time in all groups. The absence of a detectable decrease in density suggests that the modest biodegradation of CA scaffolds is balanced with processes of bone formation. Finally, both unmodified and modified CA scaffolds continued to provide a supportive surface for bone formation out to six months. Overall, results from this study suggest that CA scaffolds modified with melatonin may enhance bone remodeling activity in calvarial defects through hAMSC differentiation and recruitment and by preferentially supporting the viability and function of mature osteoblasts. This novel bioactive ceramic scaffold has the potential to change the dogma of bone grafting in fields like dentistry and reconstructive surgery. Continued optimization of this therapy is warranted and the attachment of other osteoinductive biomolecules is being considered

Prospective Clinical Study with New Materials for Tissue Regeneration: A Study in Humans

Objective: This study was performed to evaluate the clinical, radiographic, and histomorphometric outcomes of novel bone grafting materials and dental membranes and to compare the results with current data from literature. Materials and Methods: New synthetic bone substitutes, consisting of biphasic calcium phosphate, in the ratio of 60% hydroxyapatite and 40% β-tricalcium phosphate, were applied in bony defects and covered by either a novel synthetic poly(lactic-co-glycolic) acid (PLGA) or porcine collagen membrane. A sample of 51 biomaterials was placed in a total of 20 patients during different surgical protocols. Implants were simultaneously inserted, and in case of sinus floor elevations 6 months later. Pre- and postoperative cone-beam computed tomographies were taken. Bone biopsies were harvested from augmented sides and processed for histomorphometric evaluation. Statistical Analysis: Averages and ranges were calculated for the percentage of newly formed bone, residual biomaterial, and connective tissue. Data were submitted to analyze the radiological mean differences in length, width, and density. Paired t-tests were deployed for the analysis of differences within each group between the baseline (preoperative) and the final (postoperative) measurements. Results: The mean bone gain in length and width were 0.96 ± 3.33 mm (+27.59%) and 1.22 ± 1.87 mm (+30.48%), respectively. The bone density was increased by a factor of 4, reaching an average of 387.47 ± 328.86 HU. Histomorphometric evaluations revealed new bone formation of 41.44 ± 5.37%, residual biomaterial of 24.91 ± 7.32%, and connective tissue of 33.64 ± 4.81%. The mean healing period was 8.32 ± 3.00 months. Conclusions: Data from this study confirmed the suitability of the tested materials in dental surgery. The biomaterials may be recommended for various clinical procedures. A satisfactory level of increase of new bone was reported in augmented sides. No significant differences were observed between the tested membranes. PLGA might be superior to other membranes for their easier handling.Odontologí