Showing papers in "Journal of Mechanics in Medicine and Biology in 2017"

A novel approach to detect epileptic seizures using a combination of tunable-q wavelet transform and fractal dimension

Abstract: The detection and quantification of seizures can be achieved through the analysis of nonstationary electroencephalogram (EEG) signals. The detection of these intractable seizures involving human beings is a challenging and difficult task. The analysis of EEG through human inspection is prone to errors and may lead to false conclusions. The computer-aided systems have been developed to assist neurophysiologists in the identification of seizure activities accurately. We propose a new machine learning and signal processing-based automated system that can detect epileptic episodes accurately. The proposed algorithm employs a promising time-frequency tool called tunable-Q wavelet transform (TQWT) to decompose EEG signals into various sub-bands (SBs). The fractal dimensions (FDs) of the SBs have been used as the discriminating features. The TQWT has many attractive features, such as tunable oscillatory attribute and time-invariance property, which are favorable for the analysis of nonstationary and transient signals. Fractal dimension is a nonlinear chaotic trait that has been proven to be very useful in the analysis and classifications of nonstationary signals including EEG. First, we decompose EEG signals into the desired SBs. Then, we compute FD for each SB. These FDs of the SBs have been applied to the least-squares support vector machine (LS-SVM) classifier with radial basis function (RBF) kernel. We have used 10-fold cross-validation to ensure reliable performance and avoid the possible over-fitting of the model. In the proposed study, we investigate the following four popular classification tasks (CTs) related to different classes of EEG signals: (i) normal versus seizure (ii) seizure-free versus seizure (iii) nonseizure versus Seizure (iv) normal versus seizure-free. The proposed model surpassed existing models in the area under the receiver operating characteristics (ROC) curve, Matthew’s correlation coefficient (MCC), average classification accuracy (ACA), and average classification sensitivity (ACS). The proposed system attained perfect 100% ACS for all CTs considered in this study. The method achieved the highest classification accuracy as well as the largest area under ROC curve (AUC) for all classes. The salient feature of our proposed model is that, though many models exist in the literature, which gave high ACA, however, their performance has not been evaluated using MCC and AUC along with ACA simultaneously. The evaluation of the performance in terms of only ACA which may be misleading. Hence, the performance of the proposed model has been assessed not only in terms of ACA but also in terms AUC and MCC. Moreover, the performance of the model has been found to be almost equivalent to a perfect model, and the performance of the proposed model surpasses the existing models for the CTs investigated by us. Therefore, the proposed model is expected to assist clinicians in analyzing seizures accurately in less time without any error.

Classification of focal and nonfocal eeg signals using features derived from fourier-based rhythms

Abstract: We propose a new technique for the automated classification of focal and nonfocal electroencephalogram (EEG) signals using Fourier-based rhythms in this paper. The EEG rhythms, namely, delta, theta...

Analytical study of electro-osmosis modulated capillary peristaltic hemodynamics

Abstract: A mathematical model is developed to analyse electro-kinetic effects on unsteady peristaltic transport of blood in cylindrical vessels of finite length. The Newtonian viscous model is adopted. The analysis is restricted under Debye-Huckel linearization (i.e. wall zeta potential less than or equal to 25mV is sufficiently small). The transformed, non-dimensional conservation equations are derived via lubrication theory and long wavelength and the resulting linearized boundary value problem is solved exactly. The case of a thin electric double layer (i.e. where only slip electro-osmotic velocity considered) is retrieved as a particular case of the present model. The response in pumping characteristics (axial velocity, pressure gradient or difference, volumetric flow rate, local wall shear stress) to the influence of electro-osmotic effect (inverse Debye length) and Helmholtz-Smoluchowski velocity is elaborated in detail. Visualization of trapping phenomenon is also included and the bolus dynamics evolution with electro-kinetic effects examined. A comparative study of train wave propagation and single wave propagation is presented under the effects of thickness of EDL and external electric field. The study is relevant to electrophoresis in haemotology, electrohydrodynamic therapy and biomimetic electro-osmotic pumps.

Heat and mass transfer analysis on peristaltic flow of particle–fluid suspension with slip effects

Abstract: In this paper, the effect of heat and mass transfer on particle–fluid suspension due to peristaltic motion is examined with of slip effects. The governing equations of fluid phase and particulate phase for Casson fluid model with embedded particles are interpreted under the approximation of long wavelength and neglecting the inertial forces. The obtained coupled resulting partial differential equations are solved analytically and an exact form of solutions are conferred. The impact of various sundry parameters are plotted and discussed for velocity, temperature and concentration distribution for both fluid and particle phase. Numerical solution is evaluated for pressure rise along the whole channel. The present analysis reveals various interesting behavior that warrant further analysis on various Newtonian and non-Newtonian fluids. In the present flow problem, the influence of slip represents opposite attitude on the walls of the channel whereas due to the impact of particle volume fractions, the velocity...

Numerical study of slip effects on unsteady asymmetric bioconvective nanofluid flow in a porous microchannel with an expanding/contracting upper wall using buongiorno’s model

Abstract: In this paper, the unsteady fully developed forced convective flow of viscous incompressible biofluid that contains both nanoparticles and gyrotactic microorganisms in a horizontal micro-channel is studied. Buongiorno’s model is employed. The upper channel wall is either expanding or contracting and permeable and the lower wall is static and impermeable. The plate separation is therefore a function of time. Velocity, temperature, nano-particle species (mass) and motile micro-organism slip effects are taken into account at the upper wall. By using the appropriate similarity transformation for the velocity, temperature, nanoparticle volume fraction and motile microorganism density, the governing partial differential conservation equations are reduced to a set of similarity ordinary differential equations. These equations under prescribed boundary conditions are solved numerically using the Runge-Kutta-Fehlberg fourth-fifth order numerical quadrature in the MAPLE symbolic software. Excellent agreement between the present computations and solutions available in the literature (for special cases) is achieved. The key thermofluid parameters emerging are identified as Reynolds number, wall expansion ratio, Prandtl number, Brownian motion parameter, thermophoresis parameter, Lewis number, bioconvection Lewis number and bioconvection Peclet number. The influence of all these parameters on flow velocity, temperature, nano-particle volume fraction (concentration) and motile micro-organism density function is elaborated. Furthermore graphical solutions are included for skin friction, wall heat transfer rate, nano-particle mass transfer rate and micro-organism transfer rate. Increasing expansion ratio is observed to enhance temperatures and motile micro-organism density. Both nanoparticle volume fraction and microorganism increases with an increase in momentum slip. The dimensionless temperature and microorganism increases as wall expansion increases. Applications of the study arise in advanced nanomechanical bioconvection energy conversion devices, bio-nano-coolant deployment systems etc.

A novel biomechanics-based approach for person re-identification by generating dense color sift salience features

Abstract: Currently, identifying humans using biomechanics-based approaches has gained a lot of significance for person re-identification. Biomechanics-based approaches use knee-hip angle–angle relationships and body movements for person re-identification. Generally, biomechanics of human walking and running is used for person re-identification. In fact, person re-identification is a complex and important task in academia as well as industry and remains an unsolved issue in the computer vision field. The subjects most commonly addressed regarding person re-identification include significant feature extraction that can function accurately with invariant appearance and robust classification. In this study, a significant color feature descriptor is proposed by combining dense color-SIFT and global convex hull salience region features. First convex hull boundary points are detected using the SIFT technique. Furthermore, it is extended with Grubb’s outlier test to eliminate the outlier points detected by SIFT and mark t...

Automated detection of atrial fibrillation ecg signals using two stage vmd and atrial fibrillation diagnosis index

Abstract: Atrial fibrillation (AF) is a common atrial arrhythmia occurring in clinical practice and can be diagnosed using electrocardiogram (ECG) signal. The conventional diagnostic features of ECG signal a...

Peristaltic flow and hydrodynamic dispersion of a reactive micropolar fluid-simulation of chemical effects in the digestive process

Abstract: The hydrodynamic dispersion of a solute in peristaltic flow of a reactive incompressible micropolar biofluid is studied as a model of chyme transport in the human intestinal system with wall effects. The long wavelength approximation, Taylor's limiting condition and dynamic boundary conditions at the flexible walls are used to obtain the average effective dispersion coefficient in the presence of combined homogeneous and heterogeneous chemical reactions. The effects of various pertinent parameters on the effective dispersion coefficient are discussed. It is observed that average effective dispersion coefficient increases with amplitude ratio which implies that dispersion is enhanced in the presence of peristalsis. Furthermore average effective dispersion coefficient is also elevated with the micropolar rheological and wall parameters. Conversely dispersion is found to decrease with cross viscosity coefficient, homogeneous and heterogeneous chemical reaction rates. The present simulations provide an important benchmark for future chemo-fluid-structure interaction computational models.

Thermal analysis in drilling of ex vivo bovine bones

Abstract: Bone drilling is a common procedure in Medicine, mainly in traumatology and orthopedic procedure for fractures fixation and in reconstructive surgery. The success of this surgical procedure is dependent on many factors, namely, on heat generation control during the bone drilling. The main concern in bone drilling is the mechanical and thermal damage of the bone induced by inappropriate parameters such as drill speed and feed-rate during the drilling. This study focuses on the temperature generated during drilling of cortical bone tissue (bovine origin) and solid rigid polyurethane foams with similar mechanical properties to the human bone tissue. Different parameters such as drill speed, feed-rate and hole depth were tested. All results showed that improvement of the drilling parameters and the drill temperatures can be estimated. It was concluded that when the drill speed and feed-rate were higher, the bone temperature increase was lower. The obtained results of temperature in the drilling process of polyurethane foam blocks or bovine bone were compared with a good agreement in between both.

A realistic 3d computational model of the closure of skin wound with interrupted sutures

Abstract: Wounds or cuts are the most common form of skin injuries. While a shallow wound may heal over time, deep wounds often require clinical interventions such as suturing to ensure the wound closure and timely healing. To date, suturing practices are based on a surgeon’s experience and there is no benchmark to what is right or wrong. In the literature, there have been few attempts to characterize wound closure and suture mechanics using simple 2D computational models. In our current work, for the first time, a realistic three-dimensional (3D) computational model of the skin with the two layers, namely the epidermis and dermis, have been developed. A 3D diamond shaped wound with a varying cross-section has been modeled, and interrupted sutures have been placed numerically in multiple steps to close the wound. Nonlinear hyperelastic material properties have been adopted for the skin and a skin pre-stress was applied bi-axially. The force requirements for each suture were estimated numerically using a novel suture pulling technique. The suture forces were found to lie in the range of 0–5 N with a maximum value at the center. Also, the center suture was observed to require an approximately four times pull force compared to the first end suture. All these findings provide important guidelines for suturing. Additionally, the suture force can be approximated as a polynomial function of the displacement. Given a wound geometry, wound depth, skin material properties, skin pre-stress, suture wire material and cross-sectional area, using our computational model, such a relationship can be used to estimate and characterize the suture force requirements accurately. To our knowledge, such a 3D computational model of skin wound closure with interrupted sutures have not been developed till date, and would be indispensable for planning robotic surgeries and improving clinical suturing practices in the future.

A PIV comparison of the flow field and wall shear stress in rigid and compliant models of healthy carotid arteries

Abstract: Certain systems relevant to circulatory disease have walls which are neither rigid nor static, for example, the coronary arteries, the carotid artery and the heart chambers. In vitro modeling allows the fluid mechanics of the circulatory system to be studied without the ethical and safety issues associated with animal and human experiments. Computational methods in which the equations are coupled governing the flow and the elastic walls are maturing. Currently there is a lack of experimental data in compliant arterial systems to validate the numerical predictions. Previous experimental work has commonly used rigid wall boundaries, ignoring the effect of wall compliance. Particle Image Velocimetry is used to provide a direct comparison of both the flow field and wall shear stress (WSS) observed in experimental phantoms of rigid and compliant geometries representing an idealized common carotid artery. The input flow waveform and the mechanical response of the phantom are physiologically realistic. The results show that compliance affects the velocity profile within the artery. A rigid boundary causes severe overestimation of the peak WSS with a maximum relative difference of 61% occurring; showing compliance protects the artery from exposure to high magnitude WSS. This is important when trying to understand the development of diseases like atherosclerosis. The maximum, minimum and time averaged WSS in the rigid geometry was 2.3, 0.51 and 1.03Pa and in the compliant geometry 1.4, 0.58 and 0.84Pa, respectively.

Analytical solution of hyperbolic bioheat equation in spherical coordinates applied in radiofrequency heating

Abstract: This paper presents an analytical solution for the hyperbolic bioheat equation in spherical coordinates under nonuniform distributed heat source term, which is theoretically modeling the Radiofrequency Heating (RFH) technique In RFH technique a spherical electrode is inserted into the diseased tissue which leads to the heat generation there due to the imposed electromagnetic field Because of the non-Fourier behavior of biological tissues, the hyperbolic Penne’s equation is adopted as perfused thermal model The equation has been solved using Eigenvalue method and the closed form solutions are introduced The temperature profiles are determined for a sample RFH procedure in cornea and liver and the effect of perfusion term in Penne’s bioheat equation is shown The effective parameters in the RFH process such as electrode radius, power and different material are studied analytically too The derived solution can play a role of verification basis of other numerical ones in this area

Effects of hypertension and pressure gradient in a human cerebral aneurysm using fluid structure interaction simulations

Abstract: Fluid–structure interaction (FSI) simulations were carried out in a human cerebral aneurysm model with the objective of quantifying the effects of hypertension and pressure gradient on the behavior of fluid and solid mechanics. Six FSI simulations were conducted using a hyperelastic Mooney–Rivlin model. Important differences in wall shear stress (WSS), wall displacements, and effective von Mises stress are reported. The hypertension increases wall stress and displacements in the aneurysm region; however, the effects of hypertension on the hemodynamics in the aneurysm region were small. The pressure gradient affects the WSS in the aneurysm and also the displacement and wall stress on the aneurysm. Maximum wall stress with hypertension in the range of rupture strength was found.

Exact analytical solution of bioheat equation subjected to intensive moving heat source

Abstract: Presented is the analytical solution of Pennes bio-heat equation, under localized moving heat source. The thermal behavior of one-dimensional (1D) nonhomogeneous layer of biological tissue is considered with blood perfusion term and modeled under the effect of concentric moving line heat source. The procedure of the solution is Eigen function expansion. The temperature profiles are calculated for three tissues of liver, kidney, and skin. Behavior of temperature profiles are studied parametrically due to the different moving speeds. The analytical solution can be used as a verification branch for studying the practical operations such as scanning laser treatment and other numerical solutions.

Swimming dynamics of a micro-organism in a couple stress fluid: a rheological model of embryological hydrodynamic propulsion

Abstract: Mathematical simulations of embryological fluid dynamics are fundamental to improving clinical understanding of the intricate mechanisms underlying sperm locomotion. The strongly rheological nature of reproductive fluids has been established for a number of decades. Complimentary to clinical studies, mathematical models of reproductive hydrodynamics provide a deeper understanding of the intricate mechanisms involved in spermatozoa locomotion which can be of immense benefit in clarifying fertilization processes. Although numerous non-Newtonian studies of spermatozoa swimming dynamics in non-Newtonian media have been communicated, very few have addressed the micro-structural characteristics of embryological media. This family of micro-continuum models include Eringen’s micro-stretch theory, Eringen’s microfluid and micropolar constructs and V.K. Stokes’ couple-stress fluid model, all developed in the 1960s. In the present paper we implement the last of these models to examine the problem of micro-organism (spermatozoa) swimming at low Reynolds number in a homogenous embryological fluid medium with couple stress effects. The micro-organism is modeled as with Taylor’s classical approach, as an infinite flexible sheet on whose surface waves of lateral displacement are propagated. The swimming speed of the sheet and rate of work done by it are determined as function of the parameters of orbit and the couple stress fluid parameter (α). The perturbation solutions are validated with a Nakamura finite difference algorithm. The perturbation solutions reveal that the normal beat pattern is effective for both couple stress and Newtonian fluids only when the amplitude of stretching wave is small. The swimming speed is observed to decrease with couple stress fluid parameter tending to its Newtonian limit as alpha tends to infinity. However the rate of work done by the sheet decreases with α and approaches asymptotically to its Newtonian value. The present solutions also provide a good benchmark for more advanced numerical simulations of micro-organism swimming in couple-stress rheological biofluids.

Numerical analysis of temperature, screwing moment and thrust force using finite element method in bone screwing process

Abstract: In this study, the bone screwing process carried out with M3.5 cortex screw for stabilization after reduction of femur shaft fracture was investigated both experimentally and numerically. The numerical analyses were performed based on the finite element method using Deform-3D software. The friction, material model, the loading and boundary conditions were exactly identified for finite element analyses. An analytic model and software were developed, which calculate the process parameters such as screwing power and thrust power, heat transfer coefficients in order to determine the temperature distributions occurring in the screw and bone material (sawbones) during screwing process. As a result, the screwing moment and thrust force values decrease with increasing of spindle speed. On the contrary, temperature values of screw and sawbones increase with increasing of spindle speed. A good consistence between the results obtained from both experimental and numeric simulations was found during the bone screwing process.

Function and biomechanics of upper limb in post-stroke patients - a systematic review

Abstract: Current clinical services are struggling to provide the most favorable rehabilitation treatment for patients with stroke, which inspired researchers to investigate and explore the use of rehabilitation devices suitable for the patients and rehabilitation therapy. This review paper addresses the importance of biomechanical features in patients who experienced stroke to the upper limb. First and foremost, a review was done on general biomechanical description associated with motor control, shoulder, elbow, wrist and fingers joint. This included the ability of the patients to move their affected arm and the affect on peak joint torque, range of motion, joint forces, grip strength and muscle activities during the activities of daily living. In addition, we also reviewed the material properties and geometrical condition of tissue in stroke patient. The repercussions of post-stroke patient regarding the bone density, stiffness of muscle as well as the thickness of cartilage are described in this review. Based on the findings, the movement of affected stroke hand is associated with the motor control and material properties of tissue. To strengthen the motor control and maintaining tissue properties, early physical training on patients should be conducted in two to four weeks after stroke. In conclusion, this report suggests a new approach for future biomechanical studies in order to enhance the quality of physiotherapy rehabilitation peculiarly for post-stroke patients.

A computational analysis of bone formation in the cranial vault using a coupled reaction-diffusion-strain model.

Abstract: Bones of the murine cranial vault are formed by differentiation of mesenchymal cells into osteoblasts, a process that is primarily understood to be controlled by a cascade of reactions between extracellular molecules and cells We assume that the process can be modeled using Turing's reaction-diffusion equations, a mathematical model describing the pattern formation controlled by two interacting molecules (activator and inhibitor) In addition to the processes modeled by reaction-diffusion equations, we hypothesize that mechanical stimuli of the cells due to growth of the underlying brain contribute significantly to the process of cell differentiation in cranial vault development Structural analysis of the surface of the brain was conducted to explore the effects of the mechanical strain on bone formation We propose a mechanobiological model for the formation of cranial vault bones by coupling the reaction-diffusion model with structural mechanics The mathematical formulation was solved using the finite volume method The computational domain and model parameters are determined using a large collection of experimental data that provide precise three dimensional (3D) measures of murine cranial geometry and cranial vault bone formation for specific embryonic time points The results of this study suggest that mechanical strain contributes information to specific aspects of bone formation Our mechanobiological model predicts some key features of cranial vault bone formation that were verified by experimental observations including the relative location of ossification centers of individual vault bones, the pattern of cranial vault bone growth over time, and the position of cranial vault sutures

Thorax injury criteria assessment through non-lethal impact using an enhanced biomechanical model

Abstract: Ballistic injury refers to the interaction of a projectile and the human body, resulting in penetration or blunt trauma. In order to consider both consequences, a hydrodynamic elastoplastic constitutive law was implemented in a numerical FE model of the human torso to simulate soft tissues behavior and to evaluate their injury risk. This law, derived from 20% ballistic gelatin, was proven to be very efficient and biofidelic for penetrating ballistic simulation in soft tissues at very high velocity. In this study, the ability of the hydrodynamic law to simulate blunt ballistic trauma is evaluated by the replication of Bir et al.’s (2004) experiments, which is a reference test of the literature for nonpenetrating ballistic impact. Lung injury criteria were also investigated through the Bir et al.’s experiments numerical replication. Human responses were evaluated in terms of mechanical parameters, which can be global (acceleration of the body, viscous criteria and impact force) or local (stress, pressure and displacement). Output results were found to be in experimental corridors developed by Bir et al., and the maximum pressure combined with the duration of the peak of pressure in the lungs seems to be a good predictor for lung injury.

Adomian decomposition method for magnetohydrodynamic flow of blood induced by peristaltic waves

Abstract: The present investigation deals with the application of Adomian decomposition method (ADM) to blood flow through an asymmetric non-uniform channel induced by peristaltic wave in the presence of magnetic field and the velocity slip at the wall. The ADM is applied with an aim to avoid any simplifications and restrictions, which changes non-linearity of the problem as well as to provide analytical solution. The blood flowing through the vessel is assumed to be Newtonian and incompressible with constant viscosity. The analytical expressions for the axial velocity component, streamlines and wall shear stress are presented. The numerical results of these physical quantities are obtained for different values of the Reynolds number, wave number and Hartmann number. The results obtained for different values of the parameters involved in the problem under consideration show that the flow is appreciably influenced by the presence of slip velocity as well as magnetic field. From this study, we conclude that the assum...

Stress analysis of internal carotid artery with low stenosis level: the effect of material model and plaque geometry

Abstract: Stress concentration in carotid stenosis has been proven to assist plaque morphology in disease diagnosis and vulnerability. This work focuses on numerical analysis of stress and strain distributio...

Shockable versus nonshockable life-threatening ventricular arrhythmias using dwt and nonlinear features of ecg signals

Abstract: Shockable ventricular arrhythmias (VAs) such as ventricular tachycardia (VT) and ventricular fibrillation (VFib) are the life-threatening conditions requiring immediate attention. Cardiopulmonary r...

Swimming of a singly flagellated micro-organism in a magnetohydrodynamic second-order fluid

Abstract: Magnetic swimming is rapidly attracting interest in biomedical engineering applications. In the present work, we study the swimming of a singly flagellated micro-organism propelling in an electrically-conducting magnetohydrodynamic (MHD) viscoelastic second-order fluid. The singly flagellated micro-organism is modeled by a transversely waving infinite flexible sheet. The method of successive approximation is employed up to second-order in the amplitude of oscillation of the waving sheet. It has been shown that the velocity induced by a transversely waving infinite flexible sheet in a viscoelastic second-order fluid decreases with the elastic property for all the values of the Reynolds number. The solution reveals that the magnetic parameter (relating the relative influence of magnetic body force and viscous force effects) increases the propulsion for small Reynolds number and reduces it with high Reynolds number. The influence of magnetic field is therefore variable depending on the inertial effect. Comparisons with the literature demonstrate the generality of the proposed approach which allows errors included in previous formulations to be corrected. The present results may be, in principle, taken as a benchmark for computational modeling of magnetic swimming in viscoelastic fluids of relevance to green energy and magnetic biomedical procedures.

A lumped parameter model of cardiovascular system with pulsating heart for diagnostic studies

Abstract: Mathematical modeling of cardiovascular system provides an ability to study hemodynamics and to predict the results of treatment based on individual anatomical and physiological data of patients. However, the presently developed models of cardiovascular system have a limitation on use in clinical practice due to their physical and computational complexities. The aim of this study is to derive a lumped parameter model of cardiovascular system with pulsating heart in which all parameters have a physically based quantitative value and can be identified using clinical methods. For development of a cardiovascular system model the chamber analog was used which describes whole cardiovascular system as a set of elastic chambers. The proposed model consists of systemic and pulmonary circulation, four-chamber heart and four valves. The description of heart is based on a four-element representation of a cardiac muscle. The reverse blood flow via valves is considered. The accuracy of the derived model was evaluated by comparing the data of numerical simulation with experimental data. The limitations of the model were discussed as well as possible applications of the model were suggested. The proposed lumped parameter model can be used to support clinicians in their decisions in treating cardiovascular disorders.

Automated identification of coronary artery disease from short-term 12 lead electrocardiogram signals by using wavelet packet decomposition and common spatial pattern techniques

Abstract: The occlusion of the coronary arteries commonly known as coronary artery disease (CAD) restricts the normal blood circulation required to the heart muscles, thus results in an irreversible myocardi...

Implementation of a smartphone wireless gyroscope platform with machine learning for classifying disparity of a hemiplegic patellar tendon reflex pair

Abstract: The patellar tendon reflex response provides fundamental means of assessing a subject’s neurological health. Dysfunction regarding the characteristics of the reflex response may warrant the escalation to more advanced diagnostic techniques. Current strategies involve the manual elicitation of the patellar tendon reflex by a highly skilled clinician with subsequent interpretation according to an ordinal scale. The reliability of the ordinal scale approach is a topic of contention. Highly skilled clinicians have been in disagreement regarding even the observation of asymmetric reflex pairs. An alternative strategy incorporated the ubiquitous smartphone with a software application to function as a wireless gyroscope platform for quantifying the reflex response. Each gyroscope signal recording of the reflex response can be conveyed wirelessly through Internet connectivity as an email attachment. The reflex response is evoked through a potential energy impact pendulum that enables prescribed targeting and potential energy level. The smartphone functioning as a wireless gyroscope platform reveals an observationally representative gyroscope signal of the reflex response. Three notably distinguishable attributes of the reflex response are incorporated into a feature set for machine learning: maximum angular rate of rotation, minimum angular rate of rotation, and time disparity between maximum and minimum angular rate of rotation. Four machine learning platforms such as the J48 decision tree, K-nearest neighbors, logistic regression, and support vector machine, were applied to the patellar tendon reflex response feature set incorporating a hemiplegic patellar tendon reflex pair. The J48 decision tree attained 98% classification accuracy, and the K-nearest neighbors, logistic regression, and support vector machine achieved perfect classification accuracy for distinguishing between a hemiplegic affected leg and unaffected leg patellar tendon reflex pair. The research findings reveal the potential of machine learning for enabling advanced diagnostic acuity respective of the gyroscope signal of the patellar tendon reflex response.

Shoulder and elbow joint angle estimation for upper limb rehabilitation tasks using low-cost inertial and optical sensors

Abstract: This paper proposes a new method to improve accuracy and real-time performance of inertial joint angle estimation for upper limb rehabilitation applications by modeling body acceleration and adding low-cost markerless optical position sensors. A method based on a combination of the 3D rigid body kinematic equations and Denavit-Hartenberg (DH) convention is used to model body acceleration. Using this model, body acceleration measurements of the accelerometer are utilized to increase linearization order and compensate for body acceleration perturbations. To correct for the sensor-to-segment misalignment of the inertial sensors, position measurements of a low-cost markerless position sensor are used. Joint angles are estimated by Extended Kalman Filter (EKF) and compared with Unscented Kalman Filter (UKF) in terms of performance. Simulations are performed to quantify the existing error and potential improvements achievable by the proposed method. Experiments on a human test subject performing an upper limb rehabilitation task is used to validate the simulation results in realistic conditions.

Gait deviations in children with classic high-functioning autism and low-functioning autism

Abstract: The most significant symptoms of autism are abnormal movement patterns that can lead to the decrease of life quality. The purpose of the study was to compare quantitatively the gait strategy of the typical subjects, children with classic high-functioning autism (HFA), and children with low-functioning autism (LFA). Secondly, the comparison and the evaluation of main changes of plantar pressure parameters between groups were presented. The evaluation was carried out on 18 children with HFA, 10 children with LFA, and 30 age-matched children as a control group. A six camera motion capture system, two force plates and a pedobarograph were used to measure gait kinematics, joint kinetics, and pressure distribution under foot during walking. The analysis shows significant differences between children with HFA, LFA, and typical children in velocity, cadence, and magnitude of plantar pressure distribution. The magnitude of plantar pressure was reduced in children with autism under all anatomical masks, which was caused by plano-valgus deformity. Differences were also observed in joint angles and moments during gait cycle. Some of the results can be a source of important information about gait patterns in autistic children. Any exercise treatment prescribed for autistic children should focus on changing the patterns of plantar pressure distribution, which would be similar to patterns of typical children. However, the exercise treatment cannot be generalized due to the high inter-subject variability in children with autism.

Effects of footwear variations on three-dimensional kinematics and tibial accelerations of specific movements in american football

Abstract: American football is associated with a high rate of non-contact chronic injuries. Players are able to select from both high and low cut footwear. The aim of the current investigation was to examine the influence of high and low cut American football specific footwear on tibial accelerations and three-dimensional (3D) kinematics during three sport specific movements. Twelve male American football players performed three movements, run, cut and vertical jump whilst wearing both low and high cut footwear. 3D kinematics of the lower extremities were measured using an eight-camera motion analysis system alongside tibial acceleration parameters which were obtained using a shank mounted accelerometer. Tibial acceleration and 3D kinematic differences between the different footwear were examined using either repeated measures or Friedman’s ANOVA. Tibial accelerations were significantly greater in the low cut footwear in comparison to the high cut footwear for the run and cut movements. In addition, peak ankle eversion and tibial internal rotation parameters were shown to be significantly greater in the low cut footwear in the running and cutting movement conditions. The current study indicates that the utilization of low cut American football footwear for training/performance may place American footballers at increased risk from chronic injuries.

Estimation of wall shear stress using 4d flow cardiovascular mri and computational fluid dynamics

Abstract: In the last few years, wall shear stress (WSS) has arisen as a new diagnostic indicator in patients with arterial disease There is a substantial evidence that the WSS plays a significant role, together with hemodynamic indicators, in initiation and progression of the vascular diseases Estimation of WSS values, therefore, may be of clinical significance and the methods employed for its measurement are crucial for clinical community Recently, four-dimensional (4D) flow cardiovascular magnetic resonance (CMR) has been widely used in a number of applications for visualization and quantification of blood flow, and although the sensitivity to blood flow measurement has increased, it is not yet able to provide an accurate three-dimensional (3D) WSS distribution The aim of this work is to evaluate the aortic blood flow features and the associated WSS by the combination of 4D flow cardiovascular magnetic resonance (4D CMR) and computational fluid dynamics technique In particular, in this work, we used the 4D CMR to obtain the spatial domain and the boundary conditions needed to estimate the WSS within the entire thoracic aorta using computational fluid dynamics Similar WSS distributions were found for cases simulated A sensitivity analysis was done to check the accuracy of the method 4D CMR begins to be a reliable tool to estimate the WSS within the entire thoracic aorta using computational fluid dynamics The combination of both techniques may provide the ideal tool to help tackle these and other problems related to wall shear estimation