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Objective: Ultrasound is used increasingly in swallowing research because it can be a non-invasive, repeatable and cost effective measure of swallowing dynamics and rehabilitative effects. However unstable head position and transducer movement while imaging may result in measurement error that is substantive enough to bias research results. This study investigated the variation in measures of hyoid displacement and submental muscle size within and across three sessions using two methods of acquisition. Methods: Twenty-four healthy participants over the age of 50 attended three sessions. In each session, five dynamic video clips of hyoid movement and five static images of submental muscles were imaged in 2D ultrasound using two acquisition methods. One method involved manual hand-held stabilisation of the transducer and the other method involved a custom-designed stand for stabilisation of the transducer and participant. Hyoid displacement was measured as a percent change between measures made at rest and at maximal excursion. Additionally, cross sectional area (CSA) measurements were made of the paired geniohyoid and the left and right anterior belly of digastric (ABD) muscles at rest. Results: Out of 720 possible measures of hyoid displacement, 675 measures were analysed. There were no significant order effects of session or trial with changes that were <1% and no greater 4.5% for session and no greater than 1.5% for trial from estimated baseline measures. There was a significant effect of method (p<.01), with a systematic decrease in stand measures that were <9.5% and no greater than 16% from estimated baseline measures. Variance was larger across sessions than within sessions. The stand condition was more variable than the hand-held condition for measures of hyoid displacement. Out of a total of 2160 possible measures of submental muscle size, 555 measures of geniohyoid and 1408 measures of ABD muscles were analysed. There were no significant order effects of session, trial or method in geniohyoid muscle measures. The estimated order effects of session were <3% and no greater than 13%, and trials were <0.4% and no greater than 0.7% from estimated baseline measures. There were no significant order effects of session and method in ABD muscle measures with order effects of session that were <2% and no greater than 5.5%. There were significant effects of trial (p<.01) in both ABD muscles with a small systematic increase that was <0.5% and no greater than 0.8%. Variance was larger across sessions than within sessions in all measures of submental muscle size. The stand condition was less variable than the hand-held condition for all measures of submental muscle size. Conclusion: The results from this study provide guidance to researchers who intend to use repeated measures from ultrasound imaging as an outcome measure in swallowing research. The large variability within and across participants in measures of hyoid displacement and geniohyoid muscle size may require further investigation. When the variations described in this current study are considered in the measures of the ABD muscle size then it can be a valuable measure of rehabilitative techniques.

Submitted by Fernando Souza (fernando@biblioteca.ufpb.br) on 2017-10-02T13:42:54Z No. of bitstreams: 1 arquivototal.pdf: 2999468 bytes, checksum: 956cae684176d28e417f331d31b46a00 (MD5) / Made available in DSpace on 2017-10-02T13:42:54Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2999468 bytes, checksum: 956cae684176d28e417f331d31b46a00 (MD5) Previous issue date: 2017-07-29 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Incisions are a common task in most surgical procedures. Their learning is traditionally done in universities or teaching centers with the use of synthetic materials, animal parts, or, in more advanced stages, in real patients under the supervision of professionals. The use of simulators can contribute in this context of training, since with them it is possible to realistically simulate the materials used, carry out the practice repeatedly and immediately and automatically assess students' performance. Simulators capable of providing evaluation for the incision made in a given procedure are not common, and even those that exist do not have a specific assessment system for this task. The present study aimed to propose and develop an assessment system for surgical incisions simulated with computational methods, identifying the basic components of this process and using appropriate decision models for each of them. For this, the concepts and variables related to this procedure were studied, highlighting their most relevant characteristics and looking for ways to better provide assessment for them. The developed system considers two steps for the assessment of the incision, pre-surgical and surgical. The classical logic was the decision model used for most of the variables, with specific rules to deal with the particularities of each one. In order to evaluate the incision trajectory, the Support Vector Machine model was selected after experiments that compared the accuracy of the assessment of different decision models applied to databases containing rectilinear incision paths. For the validation of the system, metrics for the submental incision, component of the mandibular reconstruction procedure, used in the treatment of mandibular symphysis fractures, which has high prevalence in Brazil and in the world, were obtained and applied in an incision simulation in this region of the body. A computational incision simulation, the conceptualization of the evaluation system, a concrete implementation applied to the problem of the submental incision and conceptual maps, which systematize the knowledge used from different points of view, were produced in this work. It was verified that the assessment system responded adequately, with the classical logic rules and the Support Vector Machine providing results in accordance with the metrics used. Thus, it is observed that the assessment system proposed in this work represents an adequate tool for the use in the training of incision techniques. / As incisões são uma tarefa comum na maioria dos procedimentos cirúrgicos. O aprendizado delas é tradicionalmente feito nas universidades ou centros de ensino com o uso de materiais sintéticos, peças de animais, ou, em estágios mais avançados, em pacientes reais com a supervisão de profissionais. O uso de simuladores pode contribuir neste contexto de treinamento, uma vez que com eles é possível simular de forma realista os materiais utilizados, realizar a prática repetidas vezes e avaliar de forma imediata e automática o desempenho dos estudantes. Simuladores capazes de fornecer avaliação para a incisão feita em determinado procedimento não são comuns, e mesmo os existentes não possuem um método de avaliação específico para esta tarefa. O presente trabalho teve por objetivo propor e desenvolver um sistema de avaliação para incisões cirúrgicas simuladas com métodos computacionais, identificando os componentes básicos deste processo e empregando modelos de decisão adequados para cada um deles. Para isso, foram levantados os conceitos e as variáveis relacionadas a este procedimento, destacando suas características mais relevantes e buscando formas de melhor fornecer avaliação para eles. O sistema desenvolvido considera duas etapas para a avaliação da incisão, pré-cirúrgica e cirúrgica. A lógica clássica foi o modelo de decisão utilizado para a maior parte das variáveis, havendo regras específicas para lidar com as particularidades de cada uma. Para a avaliação da trajetória da incisão foi utilizado o modelo Support Vector Machine, selecionado após a realização de experimentos que compararam a precisão da avaliação de diferentes modelos de decisão aplicados a bancos de dados contendo caminhos de incisões retilíneas. Para a validação do sistema, métricas para a incisão submentoniana, componente do procedimento de reconstrução mandibular, utilizada no tratamento de fraturas na sínfise mandibular, o qual tem alta prevalência no Brasil e no mundo, foram obtidas e aplicadas em uma simulação de incisão nesta região do corpo. Foram produzidos então uma simulação de incisão computacional, a conceitualização do sistema de avaliação, uma implementação concreta aplicada ao problema da incisão submentoniana e mapas conceituais, que sistematizam os conhecimentos utilizados a partir de diferentes pontos de vista. Verificou-se que o sistema de avaliação respondeu adequadamente, com as regras da lógica clássica e a Support Vector Machine provendo resultados em conformidade com as métricas utilizadas. Desta forma, observa-se que o sistema de avaliação proposto neste trabalho representa uma ferramenta adequada para o uso no treinamento de técnicas de incisão.

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