Gait variability and symmetry assessment with inertial sensors for quantitative discrimination of Trendelenburg sign in total hip arthroplasty patients: a pilot study based on convenience sampling

Abstract Introduction The aim of this pilot study based on convenience sampling was to analyze the feasibility to quantitatively discriminate Trendelenburg sign (TS), a characteristic drop in pelvic position during gait in hip disfunctions, in patients with total hip arthroplasty (THA), by assessing gait variability and symmetry using inertial sensors. Methods Thirteen patients with right THA, divided into two groups with (GTS, n=4) and without TS (GnTS, n=9) assessed by experienced physician, were enrolled in the study. Harris Hip Score was applied for specific evaluation of THA. The protocol consisted in walking on a level treadmill during 3 minutes with two inertial sensors attached at anterior superior iliac spine of both sides. For each left and right step, features were extracted from the Y-axis gyroscope signals: peak value, mean absolute value, standard deviation and range. For each feature, a symmetry ratio was calculated as the ratio between left and right side. Results No significant differences were found in Harris Hip Score between groups. The variability assessed by standard deviation for left step, contralateral to the replaced side, was significantly larger for GTS group (p<0.001). Significant differences in the symmetry ratios were found between GTS and GnTS for all features extracted from gyroscopes Y-axis (W=144, p<0.001). The symmetry ratios for GnTS group were approximately equal one (except for range), whereas for the GTS group they exceed the 10% criterion. Conclusion The variability and symmetry ratios of gait features extracted from inertial sensors were successful to discriminate TS in THA patients.

Effects of backpack loads and positions on the variability of gait spatiotemporal parameters in young adults

Abstract Introduction: People carry backpacks of different weight in different positions every day. The effects of backpack wearing under different loads and positions were assessed according to the gait's spatiotemporal parameters and their variability in young adults. Methods Twenty-one subjects performed trials of 4 min in the conditions: control condition with no backpack; bilateral back load consisting of 10% body weight (BW); bilateral back load of 20% BW (B20); unilateral load of 10% BW; unilateral load with 20% BW (U20); bilateral frontal load with 10% BW; bilateral frontal load with 20% BW. Results Step length (SL) and step frequency (SF) show that frontal conditions differed from others as seen in B20. Gait cycle phases showed an increase in the B20 condition for double stance phase and stance phase, swing phase presented reduction in the B20 condition. There were significant main effects in position for SL, SF, and walk ratio, in load only for stride width. The highest variability of spatiotemporal parameters occurred in the U20 condition. All load conditions with 20% BW showed a greater variability when compared to the 10% BW counterpart. Conclusion We concluded that young adults can cope with up to a 15% BW load under a bilateral back position, but in the frontal position not even a 10% BW load was proven to be a safe limit. 20% BW loads should be avoided in any position. These recommendations may assure increased gait stability, decreased trunk forward lean and decreased muscle activation and fatigue reducing back pain occurrence.

Queimaduras no Triângulo Mineiro (Brasil): estudo epidemiológico de uma unidade de queimados / Burns in Triângulo Mineiro (Brazil): epidemiological study of a burn unit / Quemaduras en Triângulo Mineiro (Brasil): un estudio epidemiológico de la unidad de quemados

Objetivo: Caracterizar a unidade e os pacientes atendidos em uma Unidade de Queimados, entre janeiro de 2006 e dezembro de 2013. Método: Realizouse estudo epidemiológico descritivo, observacional, retrospectivo com abordagem quantitativa dos pacientes e da Unidade de Queimados, a partir de dados do serviço de estatística do hospital. Resultados: Em geral, o perfil dos pacientes atendidos nos últimos oito anos é de adultos em idade laboral e crianças menores de 10 anos, sexo masculino, vítimas de acidentes com líquidos inflamáveis ou aquecidos, apresentando queimaduras de 2° grau em cerca de 10 a 19% do corpo, sobretudo no tronco. O maior número de admissões (81) ocorreu em 2010, sendo que a maior taxa de ocupação (67,2%) da unidade se deu em 2007 e a menor (33,14%) em 2008, mesmo ano no qual foi observada a maior taxa de mortalidade (7,2%). Em contrapartida, a menor taxa de mortalidade foi observada em 2006 (1,6%). Cerca de 40% das internações tiveram duração inferior a dez dias. Dos 517 procedimentos cirúrgicos realizados dentro da unidade, 20% foram enxertos dérmico-epidérmicos. Conclusão: Houve pouca mudança no perfil epidemiológico dos atendimentos realizados nesta unidade em comparação com a década anterior. Entretanto, adequações físicas e metodológicas devem incluir estratégias focadas na criança e na perspectiva laboral de adultos.

Objective: To characterize the Burn Unit and its inpatients between January 2006 and December 2013. Methods: A descriptive, observational, retrospective epidemiological study with quantitative approach of the Burn Unit and its inpatients was performed with data from the hospital statistical service. Results: In general, the profile of the Burn Unit inpatients seen in the past eight years are adults in working age and children under 10 years old, victims of accidents with flammable and heated liquids, presenting second degree burns in about 10 to 19% of body surface area, especially on the trunk. The highest number of new admissions (81) occurred in 2010, with the highest occupancy rate in 2007 (67.2%) and lowest in 2008 (33.14%), the same year in which the highest mortality rate (7.2%) was observed. In contrast, the lowest mortality rate was observed in 2006 (1.6%). About 40% of the total admissions lasted less than ten days. From the 517 surgical procedures carried out inside the unit, 20% were dermal-epidermal grafts. Conclusion: There were little changes on the epidemiological profile of the delivered treatments in this unit when compared to the previous decade. However, physical and methodological adjustments should focus on child and on adults' occupational perspective.

Objetivo: Caracterizar una Unidad de Quemaduras y los pacientes hospitalizados entre enero de 2006 y diciembre de 2013. Métodos: Estudio descriptivo, observacional, retrospectivo epidemiológico con un enfoque cuantitativo de los pacientes y de la Unidad de Quemados, a partir de los datos del servicio de estadísticas de los hospitales. Resultados: En general, el perfil de los pacientes atendidos en los últimos ocho años son adultos en edad de trabajar y los niños menores de 10 años de edad, de sexo masculino, las víctimas de accidentes con líquidos inflamables y con calefacción, que tienen respectivamente quemaduras 2° grado en aproximadamente el 10 -19% del cuerpo, especialmente en el tronco. Mayor número de admisiones (81) se produjo en 2010, y la tasa de ocupación más elevada (67,2%) de la unidad se produjo en 2007 y el más bajo (33,14%) en el año 2008. En cuanto a la tasa de mortalidad en 2008 que era (7,2%) y la más baja fue registrada en 20 (1,6%). Alrededor del 40% de las hospitalizaciones duró menos de diez días. 517 de los procedimientos quirúrgicos realizados dentro de la unidad, el 20% eran injertos dermo-epidérmica. Conclusión: Hubo pocos cambios en el perfil epidemiológico de la atención recibida en esta unidad en comparación con la década anterior. Sin embargo, los ajustes físicos y metodológicos deben incluir estrategias centradas en el niño y la perspectiva de trabajo los adultos.

Mobile Augmented Reality enhances indoor navigation for wheelchair users

Introduction: Individuals with mobility impairments associated with lower limb disabilities often face enormous challenges to participate in routine activities and to move around various environments. For many, the use of wheelchairs is paramount to provide mobility and social inclusion. Nevertheless, they still face a number of challenges to properly function in our society. Among the many difficulties, one in particular stands out: navigating in complex internal environments (indoors). The main objective of this work is to propose an architecture based on Mobile Augmented Reality to support the development of indoor navigation systems dedicated to wheelchair users, that is also capable of recording CAD drawings of the buildings and dealing with accessibility issues for that population. Methods Overall, five main functional requirements are proposed: the ability to allow for indoor navigation by means of Mobile Augmented Reality techniques; the capacity to register and configure building CAD drawings and the position of fiducial markers, points of interest and obstacles to be avoided by the wheelchair user; the capacity to find the best route for wheelchair indoor navigation, taking stairs and other obstacles into account; allow for the visualization of virtual directional arrows in the smartphone displays; and incorporate touch or voice commands to interact with the application. The architecture is proposed as a combination of four layers: User interface; Control; Service; and Infrastructure. A proof-of-concept application was developed and tests were performed with disable volunteers operating manual and electric wheelchairs. Results The application was implemented in Java for the Android operational system. A local database was used to store the test building CAD drawings and the position of fiducial markers and points of interest. The Android Augmented Reality library was used to implement Augmented Reality and the Blender open source library handled the basis for implementing directional navigation arrows. OpenGL ES provided support for various graphics and mathematical transformations for embedded systems, such as smartphones. Experiments were performed in an academic building with various labs, classrooms and male and female bathrooms. Two disable volunteers using wheelchairs showed no difficulties to interact with the application, either by entering touch or voice commands, and to navigate within the testing environment with the help of the navigational arrows implemented by the augmented reality modules. Conclusion The novel features implemented in the proposed architecture, with special emphasis on the use of Mobile Augmented Reality and the ability to identify the best routes free of potential hazards for wheelchair users, were capable of providing significant benefits for wheelchair indoor navigation when compared to current techniques described in the literature.

Analysis of the relationship between EEG signal and aging through Linear Discriminant Analysis (LDA) / Análise das relações entre o sinal EEG e o envelhecimento através da Análise Discriminante Linear (ADL)

This paper aims to establish the correlation between statistical parameters and Electroencephalographic (EEG) signals as a function of age, in subjects without neurological disorders. EEG signals were recorded during the task of following an Archimedes spiral. There were 59 healthy subjects who voluntarily participated in this study which were divided into 7 groups, aging between 20 to 86  years from both gender, in order to identify differences and allow discrimination between the features of each group. Initially, comparisons were made among several features (F20, F50, F80, F95, Mean Frequency, Root Mean Square value, Zero Crossings, Square of the Power Spectrum, Kurtosis, Skewness, Variance, Standard Deviation and Approximate Entropy) seeking separation between young and elderly groups. Furthermore, it was sought to correlate the statistical parameters and the entire age range. For this purpose it was used Linear Discriminant Analysis  (LDA). The data were processed with MATLAB® software. Through the LDA, significant differences were observed over the distinct age ranges. The tool has satisfactorily performed the separation of discriminant features by classifying groups of subjects in function of their age range.

O objetivo deste trabalho é estabelecer as correlações entre parâmetros estatísticos e EEG em função da idade, em indivíduos não portadores de distúrbios neurológicos. Os sinais EEG foram registrados durante a tarefa de seguir uma espiral de Arquimedes. 59 indivíduos saudáveis participaram do estudo e foram divididos em 7 grupos, com idades entre 20 a 86 anos, de ambos os sexos, para identificar diferenças e permitir a discriminação entre as características de cada grupo. Inicialmente, foram feitas comparações entre as diversas variáveis (F20, F50, F80, F95, Frequência Média, RMS, Cruzamentos por zero, Quadrado do Espectro de Potência, Curtose, Assimetria, Variância, Desvio Padrão e Entropia Aproximada) procurando a separação entre os grupos jovem e idoso. Buscou-se ainda correlacionar os parâmetros estatísticos e toda a faixa etária. Para tal, a técnica de Análise Discriminante Linear (ADL) foi utilizada. Os dados foram processados com o software MATLAB®. Por meio da ADL foram observadas diferenças significativas ao longo da idade. Observou-se que a ferramenta executou de forma satisfatória a separação de características discriminantes, classificando cada grupo de indivíduos em função da idade.