Gait Analysis
Ali Maleki; Elham Hasani
Volume 16, Issue 3 , December 2022, , Pages 217-228
Abstract
Parkinson's disease is a neurodegenerative disease that causes severe movement disorders including bradykinesia, rigidity, and tremors. There is no cure for Parkinson's disease, only the symptoms can be managed. Parkinson's disease is diagnosed using the MDS-UPDRS global grading scale. In this scale, ...
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Parkinson's disease is a neurodegenerative disease that causes severe movement disorders including bradykinesia, rigidity, and tremors. There is no cure for Parkinson's disease, only the symptoms can be managed. Parkinson's disease is diagnosed using the MDS-UPDRS global grading scale. In this scale, four levels including slight, mild, moderate, and severe levels are defined for the disease. Recurrence plots and RQA features are tools for describing the behavior of chaotic systems and revealing hidden patterns in system dynamics. In this paper, the effect of Parkinson's disease progression on RQA chaotic features is studied. For this purpose, the dataset of the accelerometer mounted on the hand during the finger tapping test was used, which included 67 healthy data, 54 level one data, 66 level two data, 59 level three data, and 14 level four data. After pre-processing, the recurrence plots of the data were drawn and their RQA characteristics were calculated. Patterns of recurrence plots including separate recurrence points, diagonal lines, vertical lines, black squares, and horizontal and vertical white bands were investigated. According to the obtained results, the patterns of recurrence plots had significant differences among different levels of Parkinson's disease. Therefore, RQA features can be used to automatically determine the level of Parkinson's disease.
Gait Analysis
Seyed Mehran Ayati Najafabadi; Alireza Hashemi Oskouei; Seyed Masoud Rafiaei
Volume 15, Issue 2 , August 2021, , Pages 141-150
Abstract
Balance in daily movements like as stair ascending is a challenge for the people with leg lengths discrepancy (LLD). These people change their pattern of movement to compensate the difference between legs’ length. Due to the changes in movement pattern, body's center of mass which is one of the ...
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Balance in daily movements like as stair ascending is a challenge for the people with leg lengths discrepancy (LLD). These people change their pattern of movement to compensate the difference between legs’ length. Due to the changes in movement pattern, body's center of mass which is one of the important factors in maintaining balance can be varied. Compensatory insoles are used to compensate for short legs. The aim of this study is to investigate changes in the center of mass, with and without using insoles in people with leg length discrepancy when climbing stairs. In this practical cross-sectional study, the movement of 20 participants while climbing stairs in two groups of healthy people and people with LLD was recorded by a three-dimensional movement analysis system. Changes in pelvic, knee and ankle joint angles were calculated with the 7-member Euler method. Then the rotation and transferring matrixes were defined by using the joint angles to determine the torque arm of the limbs. By the total body torque method, the center of mass changes in three directions were obtained. Then, these changes were compared between the experimental and control groups using independent and paired t-test at 95% confidence level. The results showed that the displacement of the center of mass in all three directions was significantly higher for people with different leg length differences when comparing with healthy people (p<0.05). The results also showed that range of movement has no significant different in the Vertical axis between normal and LLD people (p>0.05) when using insole. Based on the findings of this study, it can be concluded that the use of compensatory insoles alone cannot make changes in the center of mass as one of the indicators to measure the balance in climbing stairs like normal people.
Gait Analysis
Fatemeh Akbarifar; Mohammad Hadi Honarvar; Mostafa Haj Lotfalian
Volume 15, Issue 1 , May 2021, , Pages 1-11
Abstract
Finding the center of rotation (COR) is needed for defining the anatomical axis of the skeletal system and for the kinematic calculation of joints in biomechanical studies. For this purpose, predictive and functional methods can be used. In the predictive methods, regression equations obtained from anthropometric ...
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Finding the center of rotation (COR) is needed for defining the anatomical axis of the skeletal system and for the kinematic calculation of joints in biomechanical studies. For this purpose, predictive and functional methods can be used. In the predictive methods, regression equations obtained from anthropometric measurements are used, and in the functional methods, the relative motion of the two adjacent segments is used to find COR. The purpose of this study is to formulate the circle fitting algorithm as a functional method with two analytical and optimization solutions. In order to evaluate the algorithm, error analysis was performed by both analytical and numerical methods. Also, effective factors in error estimating of COR position such as standard deviation of measurement system error (σ), rotation angle (α) and the distance between marker and COR (r), was evaluated. The results showed a high correlation (r=0.99) between analytical and numerical solution, which proved the accuracy of the error analysis. In this study, optimization method according to the accuracy of better estimates in low quantities α, less influence on high quantities σ and high speed in problem solving, can be taken into consideration to reconstruct human movements in biomechanical studies. Use of functional methods, eliminates the need for attaching markers to anatomical landmarks and provides a new development in motion data acquisition.
Gait Analysis
Seyed Mehran Ayati Najafabadi; Alireza Hashemi Oskooi; Seyed Masoud Rafiaei
Volume 15, Issue 1 , May 2021, , Pages 73-85
Abstract
People who suffer from leg length discrepancy (LLD) due to the shortening of one side of the lower extremities change their movement pattern because of using compensatory mechanisms. Methods such as manipulating a compensating insole are used to correct the movement pattern to normal. Therefore, the ...
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People who suffer from leg length discrepancy (LLD) due to the shortening of one side of the lower extremities change their movement pattern because of using compensatory mechanisms. Methods such as manipulating a compensating insole are used to correct the movement pattern to normal. Therefore, the knowledge of movement pattern changes in with and without using of insoles can help to develop rehabilitation methods. The aim of this study was to investigate the kinematics of the lower extremities of people with leg length discrepancy during stair climbing with and without using insoles. Twenty participants including 10 normal and 10 LLD people took part in this study. Their movement on stair was recorded using a 7 camera 3-D motion analysis system. Changes in the angles of the hip, the knee and the ankle joints were calculated by the 7-member Euler model and compared by independent and paired sample t-test at 95% confidence level. The results showed that there was a significant difference between healthy people and people with LLD without using insoles. These people had higher extension of the knee, pelvis and ankle at the initial contact and toe off in sagittal plane and more knee and pelvis range of movement, less adduction of the knee and pelvis at the initial contact in frontal plane, higher internal and external rotation of pelvis at the initial contact and ankle in toe off in horizontal plane (p<0.05). The results also showed that maximum abduction of the pelvis and maximum adduction of the ankle, maximum internal rotation and the value of the angle of the knee and ankle had no significant different between normal and LLD people (p>0.05) when using insoles. Therefore, the use of insoles can correct some parameters of the movement pattern of the lower joints.
Gait Analysis
Maryam Hajizadeh; Alireza Hashemi Oskouei; Farzan Ghalichi
Volume 11, Issue 3 , September 2017, , Pages 201-210
Abstract
Anterior cruciate ligament (ACL) rupture is one of the most costly knee injuries, usually occurring to young athletes, often leading to functional instability, inability to return to previous levels of physical activity, and premature osteoarthritis (OA). The main function of ACL is controlling anterior ...
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Anterior cruciate ligament (ACL) rupture is one of the most costly knee injuries, usually occurring to young athletes, often leading to functional instability, inability to return to previous levels of physical activity, and premature osteoarthritis (OA). The main function of ACL is controlling anterior tibia translation as well as axial tibia rotation. Therefore, patients with ACL deficiency (ACLD) have to use different compensatory mechanisms and kinematic changes to maintain their stability during different activities. The study aims to measure the reliability of knee kinematics and ground reaction force during stair negotiation. Fifteen participants with unilateral ACLD ascended 4-step staircase, where 8-10 reflective markers was inserted on each segment of lower extremity. Five-camera VICON system and 10-camera VICON system were used in the first and second phase of study, respectively. Intra-class correlation coefficient (ICC) and standard error of measurement (SEM) was calculated for each parameter in the knee events during stair climbing. The results showed high consistency of kinematic parameters and GRF components was handled through reliability and repeatability calculations. ICC (2,5) showed similar values in injured and healthy contralateral leg with the range of (0.59-0.98) for all knee joint rotation and GRF components.
Gait Analysis
Maryam Hajizade; Alireza Hashemi Oskouei; Farzan Ghalichi; Farhad Tabatabai Ghomshe; Mohammad Razi; Gisela Solo
Volume 9, Issue 1 , April 2015, , Pages 17-31
Abstract
Patients with ACL deficiency (ACLD) have to use different compensatory mechanisms to maintain their stability during daily activities. The aim of this study is to determine the differences in 3D kinematics and peak ground reaction forces (GRF) between ACL deficient legs and healthy contralateral legs ...
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Patients with ACL deficiency (ACLD) have to use different compensatory mechanisms to maintain their stability during daily activities. The aim of this study is to determine the differences in 3D kinematics and peak ground reaction forces (GRF) between ACL deficient legs and healthy contralateral legs during stair ascent. Eight subjects with unilateral ACL deficiency participated in this study. Healthy contralateral legs were considered as control group for further comparisons to ACL deficient legs. A six camera VICON motion analysis system and 2 portable force plates were used to record the locomotion while walking up custom-made stairs with two different step heights. Advanced OSSCA technique was used to assess tibiofemoral knee kinematics, a combination of symmetrical axis of rotation (SARA), symmetrical center of rotation estimation (SCoRE) and optimal common shape technique (OCST). The results of this study show that participants with ACLD experienced different kinematics and peak GRFs in different step heights (p<0.05). During ascending stairs with 17cm height, legs with ACLD exhibited less varus, more external rotation and less impact peak in pre-swing stance and early swing phase compared to contralateral healthy leg (p<0.05). The other stair height, 20 cm, resulted in more extension, more valgus and more external tibia rotation in injured leg compared to contralateral leg during terminal extension of stance phase (p<0.05). In both step heights, injured leg reached it maximum extension peak at an earlier time. The results of this study imply that participants with ACLD make use of different 3D rotational tiobiofemoral kinematics and different GRF compared to healthy contralateral leg. These compensatory mechanisms would finally bring about different knee joint loading, which provides the potential of cartilage degeneration and early osteoarthritis.
Biomedical Signal Processing / Medical Signal Processing / Biosignal Processing
Alireza Mirjalili; Vahid Abootalebi; Mohammad Taghi Sadeghi
Volume 8, Issue 4 , February 2015, , Pages 305-323
Abstract
In recent years, Brain-Computer Interface (BCI) has been noted as a new means of communication between the human brain and his surroundings. In order to set up such a system, the collaboration of several blocks, such as data recording, signal processing and user interface are needed. The signal processing ...
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In recent years, Brain-Computer Interface (BCI) has been noted as a new means of communication between the human brain and his surroundings. In order to set up such a system, the collaboration of several blocks, such as data recording, signal processing and user interface are needed. The signal processing block, includes two units of preprocessing and pattern recognition. Pattern recognition block itself involves two phases: feature extraction and classification. In this paper, the sparse representation based classification (SRC) has been used in the classification block. There are two important issues in using the SRC. These are creating an appropriate dictionary matrix and adopting a proper method for finding the sparse solution for an input data. In this research study, the dictionary matrix is formed by extracting an optimal set of features from the training data. Toward this goal, the common spatial patterns algorithm (CSP) is first used. Sensitivity to noise and the over learning phenomena are the main drawbacks of the CSP algorithm. In order to remove these problems, the regularized common spatial patterns algorithm (RCSP) is employed. In previous studies in within the BCI framework, the standard BP algorithm has been used to find a sparse solution. The main disadvantage of the BP algorithm is that the method is computationally expensive. To overcome this weakness, a recently proposed algorithm namely the SL0 approach is used instead. Our experimental results show that when the number of training samples is limited, the RCSP algorithm outperforms the CSP one. Using the features derived from the RCSP, the average detection rate is in average increased by a factor of 7.53%. Our classification results also show that using the SL0 algorithm, the classification process is highly speeded up as compared to the BP algorithm while an almost equivalent accuracy is achieved.
Gait Analysis
Ghazaleh Soleimani; Mehran Emadi Andani; Hamid Reza Marateb; Fariba Bahrami
Volume 9, Issue 4 , February 2015, , Pages 361-374
Abstract
Walking is one of the most widely used movements affecting life quality. Therefore, the study of factors affecting human gait has always been an important issue. Walking speed, as a physical perturbation, affects the quality of human walking. The purpose of this study is to estimate the effects of walking ...
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Walking is one of the most widely used movements affecting life quality. Therefore, the study of factors affecting human gait has always been an important issue. Walking speed, as a physical perturbation, affects the quality of human walking. The purpose of this study is to estimate the effects of walking speed on the short-time gait parameters. Thirty-two healthy subjects(mean SD, age: 27.56 ± 20.4 years; body height: 158.19 ± 20.83 cm; body weight: 54.89 ± 20.59 kg;gender: 59% female)participated in this study.Kinetic, kinematic and electromyographic data were recorded at the following five walking speed categories: very slow, slow, medium, fast and very fast. The effect of speed on spatio-temporal parameters, muscle synergy space, walking smoothness, representation of joints displacement and the correlation between lower limb displacement and also correlation between muscles activation patterns were studied. Having being used physical perturbation, 46 predictors were extracted from one gait cycle information, some of which were proposed for the first time inthe literature for example size of muscle synergy, minimum angular jerk, lower limb contributions and skewness, kurtosis and curvature of joints movements . Using muscle synergies showed that increasing walking speed leads to increase the size of synergy space. It could be concluded that central nervous system tries to adopt more organaized strategy for recruiting muscles and remaining stable at fast speeds. Our results showed that, speed plays a crucial role in human gait characteristic. We can investigate our methods among more subjects and also patients with gait disorders. We can evaluate other indices like gait stability based on short-term data recording.
Biomedical Signal Processing / Medical Signal Processing / Biosignal Processing
Sanaz Ahmadzadeh; Hamid Reza Kobravi; Saeed Tosizadeh
Volume 8, Issue 3 , September 2014, , Pages 293-304
Abstract
Multiple muscle groups may be activated simultaneously during the most of activities. So, the appropriate muscle coordination must be emerged during a normal activity. Consequaently, for rehabilitation of movements such as hand writing and paiting in patients for example suffering from carpal channel ...
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Multiple muscle groups may be activated simultaneously during the most of activities. So, the appropriate muscle coordination must be emerged during a normal activity. Consequaently, for rehabilitation of movements such as hand writing and paiting in patients for example suffering from carpal channel syndrom or incomplete spinal cord injury, the correct muscle coordination patterns between the finger muscles and wrist muscles must be reestablished. So, in this paper a prediction methodology based on artificial neural networks (ANN) is proposed to approximate the Thumb fingure extensor and flexor muscles desired activation pattern during the hand writing and Painting. In the presented strategy, A nonlinear auto-regressive neural network (NARX), Recurrent Neural Network (RNN), Radial Basis Function (RBF), Multy Layer Perceptron (MLP) and an Adaptive-network-based fuzzy inference system (ANFIS) are trained to forecast the Extensor pollicis longus and Flexor pollicis brevis muscles activity of one thumb finger of hand using Extensor carpi radialis brevis and Flexor carpi ulnaris muscles activity of forearm. Quantitative evaluations show the promising performance of developed neural networks. Eight healthy volunteers participated in the experiments.
Neuro-Muscular Engineering
Sohrab Barimani; Ali Maleki; Ali Fallah
Volume 8, Issue 1 , March 2014, , Pages 101-111
Abstract
FES based method used for rehabilitation of patients with spinal cord injury (SCI). One of these methods is FES cycling. FES cycling exercise has to be useful among SCI patients because of creating a periodic activity in the muscles of the lower extremities and stability of seating position. The major ...
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FES based method used for rehabilitation of patients with spinal cord injury (SCI). One of these methods is FES cycling. FES cycling exercise has to be useful among SCI patients because of creating a periodic activity in the muscles of the lower extremities and stability of seating position. The major challenge for application of FES in rehabilitation is early fatigue occurrence in electrically stimulated muscles. Motor control system selects a low-cost path among the infinite possible route to the body's movements. High efficiency and the minimum rate of muscle fatigue are main characteristics of the motor control system. This type of control system is called muscle synergy. In this study, the quantification of muscle synergy between the core muscles in cycling has been done by non-negative matrix factorization (NMF) method and considering the kinesiology basis. Four synergies were determined as appropriate and optimal synergies to describe the cycling in different mechanical terms. VAF criteria with regard to the four synergies to describe cycling in speeds of 40, 50 and 60 rpm are 92±4, 92±3 and 91±4% respectively and torques, 5, 7 and 9 Nm are 91±3, 92±5 and 92±4% respectively. Correlation between Synergies extracted at different mechanical terms is 98.4 percent in average.
Rehabilitation Engineering
Ziba Gandomkar; Fariba Bahrami
Volume 7, Issue 1 , June 2013, , Pages 21-37
Abstract
Changes in gait pattern are early symptoms in many disorders such as balance and control problems resulted in fall among elderlies. This paper aims at proposing a new set of features extracted from Gait Frieze Pattern (GFP) in order to classify seniors to fallers and non-fallers. For indicating the effectiveness ...
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Changes in gait pattern are early symptoms in many disorders such as balance and control problems resulted in fall among elderlies. This paper aims at proposing a new set of features extracted from Gait Frieze Pattern (GFP) in order to classify seniors to fallers and non-fallers. For indicating the effectiveness of the presented method, the algorithm is used for recognition of different type of abnormal gaits. The introduced method consists of three main steps: extracting the subject from background, generating GFP and aligning them, and building the proposed image from GFP by thresholding followed by morphological operations. For evaluation of the proposed features, video sequences are collected from 8 elderly fallers, 8 non-fallers, and 8 youth while performing standard Timed Up and Go (TUG) test. In addition to TUG test youths are asked to walk fast and pretend to walk with 6 different types of abnormalities (limping, waddling, anterior- posterior sway, lateral sway, dragging, steppage gait). For finding correct classification rate, each time one data is considered as test and others as train and label of train data with the most similarity with test one on the score of normalized cross correlation is assigned to test data. Comparing to conventional TUG test, correct classification data is improved around 20% for faller detection. In addition, correct classification rate for detecting of different abnormalities in gait is approximately 90%.
Rehabilitation Engineering
Mohammad Salehi Amini; Siavash Kazemirad; Saman Mohammadi; Roya Narimani; Farzam Farahmand
Volume 7, Issue 2 , June 2013, , Pages 121-132
Abstract
The purpose of this study was to design, analyze and evaluate an effective low-cost driving mechanism for gait trainer. The crank-rocker mechanism was favored for reproducing the path of foot during gait cycle, considering the type of motion and design parameters such as adjustability for different anthropometries, ...
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The purpose of this study was to design, analyze and evaluate an effective low-cost driving mechanism for gait trainer. The crank-rocker mechanism was favored for reproducing the path of foot during gait cycle, considering the type of motion and design parameters such as adjustability for different anthropometries, providing sufficient space for interactions with physical therapist, and simplicity of execution. The dimensions of the mechanism were determined using optimization method while applying appropriate constraints so that the normal gait pattern, particularly of stance phase, was obtained. A 2-D model of the lower limb was developed to simulate the gait of a patient when using the mechanism. Results indicated that with appropriate positioning of the patient, the kinematic and kinetic patterns of the normal gait are reconstructed with no risk of injury. However, there is a high risk of injury of the knee articular surfaces and ligaments, if the patient is positioned only 3 cm higher than designed height.
Rehabilitation Engineering
Rahele Mohammadi; Ali Mahloojifar
Volume 7, Issue 1 , June 2013, , Pages 39-55
Abstract
A critical issue in designing a self-paced brain computer interface (BCI) system is onset detection of the mental task from the continuous electroencephalogram (EEG) signal to produce a brain switch. This work shows significant improvement in a movement based self-paced BCI by applying a new sparse learning ...
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A critical issue in designing a self-paced brain computer interface (BCI) system is onset detection of the mental task from the continuous electroencephalogram (EEG) signal to produce a brain switch. This work shows significant improvement in a movement based self-paced BCI by applying a new sparse learning classification algorithm, probabilistic classification vector machines (PCVMs) to classify EEG signal. Constant-Q filters instead of constant bandwidth filters for frequency decomposition are also shown to enhance the discrimination of movement related patterns from EEG patterns associated with idle state. Analysis of the data recorded from seven subjects executing foot movement using the constant-Q filters and PCVMs shows a statistically significant 16% (p<0.03) average improvement in true positive rate (TPR) and a 2% (p<0.03) reduction in false positive rate (FPR) compared with applying constant bandwidth filters and SVM classifier.
Gait Analysis
Samane Moeini Sedeh; Navid Arjmand; Mohammad Ali Sanjari; Hamid Reza Mokhtarinia; Morteza Asgari; Mohammad Parnianpour
Volume 7, Issue 4 , June 2013, , Pages 333-340
Abstract
Stability is important to prevent falling during occupational and daily living activities. Control parameters such as direction of motion and external load can affect stability pattern. The purpose of this paper was to evaluate the effect of the mentioned control parameters on stability. Time series ...
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Stability is important to prevent falling during occupational and daily living activities. Control parameters such as direction of motion and external load can affect stability pattern. The purpose of this paper was to evaluate the effect of the mentioned control parameters on stability. Time series of lumbar rotation angle in 19 healthy subjects were investigated. Each subject performed spine flexionextension in two different directions of symmetric (sagittal plane) and asymmetric (between sagittal and transverse planes), with two loading cases of 8 Kg weight and load free. To evaluate dynamic stability of repetitive movement, a nonlinear method of largest Lyapunov exponent has been used. After calculating maximum Lyapunov exponent from each of the experimental cases, results of analysis of variance showed a significant difference between symmetric and asymmetric directions (p=0.016). To interpret this result we can suggest higher recruitment of the internal and external oblique muscle groups and higher mechanical constraints in spine during asymmetric tasks. Mean comparison showed that movement in symmetric direction has more instability than the asymmetric case. Moreover, presence of load and interaction between direction and load did not significantly affect local dynamic stability.
Gait Analysis
Afsaneh Yavari; Mostafa Rostami; Ali Esteki; Ali Tanbakoosaz; Mehdi Yousefi Azar Khanian
Volume 7, Issue 1 , June 2013, , Pages 75-84
Abstract
Most of the recent biomechanical researches have been focused on the stability of people with disabilities and a few researches have been done on the athletes with high balance skill.The methods of elite athletes in keeping the balance can state valuable information about balance strategies and effective ...
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Most of the recent biomechanical researches have been focused on the stability of people with disabilities and a few researches have been done on the athletes with high balance skill.The methods of elite athletes in keeping the balance can state valuable information about balance strategies and effective parameters on balance. In this study we calculate local dynamical stability of musculoskeletal systems during a hard balance motion. Eight non elite athletes and six elite athletes in Wushu participatedin this study. Kinematic parameters for quantitative assessment of postural fluctuations were recorded by VICON ® Motion Analysis System. Using Lyapunov stability theory, stability and preparation of athletes were evaluated and the best model in performing the balance motion was shown to the coaches. Results from this study showed that motion pattern and preparation of athletes are effective in the displacements of center of mass and center of pressure and finally the stability of athletes.
Gait Analysis
Mohammad Iman Mokhlespour Esfahani; Omid Zobeiri; Ali Akbari; Behzad Moshiri; Mohammad Parnianpour
Volume 7, Issue 4 , June 2013, , Pages 361-369
Abstract
Wearable measuring system has major effects onbiomechanics of human movements especially in daily activitiesin order to monitor and analyze the human movements to achievethe most important kinematics parameters. In the recent decade,inertial sensors were utilized by researchers in order todeveloping ...
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Wearable measuring system has major effects onbiomechanics of human movements especially in daily activitiesin order to monitor and analyze the human movements to achievethe most important kinematics parameters. In the recent decade,inertial sensors were utilized by researchers in order todeveloping wearable system for instrumentation of humanmovements. In this study, Sharif-Human MovementInstrumentation System (SHARIF-HMIS) was designed andmanufactured. The system consists of inertial measurement units(IMUs), stretchable clothing and data logger. The IMU sensorsare installed on the human body. The system can be used at homeand also industrial environments. The main features of thissystem are: low cost, low weight, saving data for ten hours andbeing wearable. Furthermore, the software was designed for data acquisition of the IMUs.
Biomedical Signal Processing / Medical Signal Processing / Biosignal Processing
Rahele Mohammadi; Ali Mahloojifar
Volume 6, Issue 2 , June 2012, , Pages 141-152
Abstract
Self-paced BCI systems are more natural for real-life applications since these systems allow the user to control the system when desired. Detection of event periods in continuous EEG signal is one of the most important challenges in designing self-paced BCIs. In this paper, the Event related synchronization ...
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Self-paced BCI systems are more natural for real-life applications since these systems allow the user to control the system when desired. Detection of event periods in continuous EEG signal is one of the most important challenges in designing self-paced BCIs. In this paper, the Event related synchronization (ERS) is extracted from idle EEG signal using fractal dimensions in frequency range from 6 to 36 Hz and sparse representation based classifier. Our proposed method applied on EEG signal recorded during executing foot movement in 7 subjects. The average true positive rate and false positive rate equal to 90% and 5% were achieved.
Neuro-Muscular Engineering
Abed Khorasani; Abbas Erfanian Omidvar
Volume 5, Issue 3 , June 2011, , Pages 245-255
Abstract
During the last decade, functional neuromuscular stimulation (FNS) has been proposed as a potential technique for restoring motor function in paralyzed limbs. A major challenge to restoring a desired functional limb movement through the use of intramuscular stimulation is the development of a robust ...
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During the last decade, functional neuromuscular stimulation (FNS) has been proposed as a potential technique for restoring motor function in paralyzed limbs. A major challenge to restoring a desired functional limb movement through the use of intramuscular stimulation is the development of a robust control strategy for determining the stimulation patterns. A major impediment to stimulating the paralyzed limbs and determining the stimulation pattern has been the highly non-linear, time-varying properties of electrically stimulated muscle, muscle fatigue, large latency and time constant which limit the utility of pre-specified stimulation pattern and open-loop FES control system. In this paper we present a robust strategy for multi-joint control through intramuscular stimulation in which the system parameters are adapted online and the controller requires no offline training phase. The method is based on the combination of sliding mode control with fuzzy logic and neural control. Extensive experiments on three rats are provided to demonstrate the robustness, stability, and tracking accuracy of the proposed method. The results show that the proposed strategy can provide accurate tracking control with fast convergence.
Neuro-Muscular Engineering
Mehdi Borjkhani; Farzad Towhidkhah
Volume 4, Issue 2 , June 2010, , Pages 109-122
Abstract
Writing is one of the high practiced and complex movement skills of human. Most of the proposed models for writing are bottom-up models, and therefore they could not reflect the biological aspects of movements in this process. Also there is not any model for illustrating the role of different parts of ...
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Writing is one of the high practiced and complex movement skills of human. Most of the proposed models for writing are bottom-up models, and therefore they could not reflect the biological aspects of movements in this process. Also there is not any model for illustrating the role of different parts of the brain in this task. In this paper we are going to describe some neurological and physiological aspects of the brain operation in the writing task. Then some evidence of prediction in writing and existence of internal models for limbs such as hand are presented. According to these, modeling of writing using model predictive control (MPC) is possible. Based on the presented simulations and experimental results it seems that the modeling of writing by MPC is very similar to the real skill, The proposed model has some advantages such as being consistent with the biological evidence, modeling prediction in writing and high correlation of the statical and dynamical features of the generated letters with those written by human.
Rehabilitation Engineering
Robabe Vatanparast; Hossein Karimi; Fariba Bahrami; Roya Narimani
Volume 3, Issue 3 , June 2009, , Pages 171-178
Abstract
CNS applies Anticipatory Postural Adjustments (APA) strategy to reject or minimize perturbation during different voluntary movements. The postural control mechanisms associated with voluntary arm movement (rapid arm rising) in below knee amputees (BKA) was investigated and the results were compared with ...
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CNS applies Anticipatory Postural Adjustments (APA) strategy to reject or minimize perturbation during different voluntary movements. The postural control mechanisms associated with voluntary arm movement (rapid arm rising) in below knee amputees (BKA) was investigated and the results were compared with the normal subjects. Biomechanical variables including ground reaction forces and displacements of the center of pressure were used to investigate the APA in BKA. Six below knee amputees and six control subjects stood on a force plate under three conditions: 1. with both feet on the platform, 2. with right foot (prosthetic foot) and 3. with left foot on the plate. For each condition, the task was repeated 10 times. At the same time, a camera recorded the task performance. The recorded data were used to determine the start moment of the movement. The instant at which, for the first time before starting the movement, any one of the recorded biomechanical variables deviated from its initial value was considered as the beginning of the APA. To increase the validity of the test, efforts were made to match the subjects with regards to their age, gender, cause of amputation and prosthesis types. Our results indicated that the center of pressure in the BKA participants showed greater displacements in medial-lateral and anterior-posterior directions. It was also observed that the vertical components of the ground reaction forces, when the right foot was on the plate, were increased. There were no significant differences in other biomechanical variables between the two groups. We may conclude that the voluntary arm movement perturbs the posture in the BKA participants more than in the control group. The BKA participants shifted their weight to the intact limb by the anticipation of the disturbance to avoid balance loosing. Therefore, in our study the intact limb in below knee amputee subjects played an important role in the balance control. Based on our results, we suggest considering the role of the intact limb in the rehabilitation programs and strengthening the muscles of both limbs as a major part of theses programs.
Gait Analysis
Mohsen Sadeghi Mehr; Davoud Naderi; Nader Farahpour; Saeed Davoud Abadi Farahani
Volume 3, Issue 3 , June 2009, , Pages 179-187
Abstract
The present study was devoted to determine the standing human body reactions to perturbation of a base plate in the frontal plane, in order to preserve its stability. A base plate with sinusoidal fluctuation was designed and built and then markers were mounted on the specified locations on it and the ...
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The present study was devoted to determine the standing human body reactions to perturbation of a base plate in the frontal plane, in order to preserve its stability. A base plate with sinusoidal fluctuation was designed and built and then markers were mounted on the specified locations on it and the skin of subjects before testing. During testing the subjects (N=10) tried to preserve their stability against perturbations. By using Motion Analysis System, the body responses of subjects were analyzed. Using inverse dynamic methods and experimental kinematic results, forces and moments applied to the joints and between feet soles and the base plate were determined. In theoretical study, the kinematic and dynamic equations of motion of a robotic model of human body in frontal plane by using repetitive Newton-Euler method were obtained. Based on the stability of the model and supporting vertical forces criterion an object function was defined, in order to assure the stability of the model. By optimization of the object function, angle of the model joints under perturbation and its first and second derivatives were determined. The good agreement of the theoretical and experimental results states that in similar conditions a robotic model can be used instead of expensive and time-consuming experiments.
Neuro-Muscular Engineering
Davoud Naderi; Mohsen Sadeghi Mehr; Nader Farahpour; Behnam Miripour-Fard
Volume 2, Issue 2 , June 2008, , Pages 85-93
Abstract
Cognition of human postural responses can provide valuable insight on the control of stability. Researchers can use this finding to design rehabilitation exercises to improve the patients, balance. This study was done with the aim of conducting theoretical and experimental investigations on human response ...
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Cognition of human postural responses can provide valuable insight on the control of stability. Researchers can use this finding to design rehabilitation exercises to improve the patients, balance. This study was done with the aim of conducting theoretical and experimental investigations on human response to tilting base plate in the sagittal plane. A four-segment model with three degrees of freedom was used as a biomechanical model of human body and its motion was studied in the sagittal plane. The postures of model were found by optimization technique such that the stability of model to be optimum. Zero moment point stability criterion was applied to find the optimum posture against the tilting base plate. To verify the theoretical results experimentally, the stability measure device was designed and manufactured. In several trials, the responses of ten male healthy persons standing on a tilting platform under perturbations were recorded by using the motion analysis system. Through data analysis, the response of each subject was surveyed and the experimental and theoretical results were compared. Both the experimental and theoretical results showed that the human central nervous system evokes the ankle strategy to keep its balance under tilting base plate conditions. A good coincident between the experimental results and theoretical predictions was observed, indicating that the model basis optimization method can be well relied upon to predict the human joints angle trajectories in response to base plate tilting.
Rehabilitation Engineering
Hamed Ghomashchi; Ali Esteki; Ali Motie Nasrabadi
Volume 2, Issue 2 , June 2008, , Pages 95-107
Abstract
In this study, the underlying dynamics of postural control system during quiet standing were investigated. Single-subject (SS) analysis was used as the statistical technique to compare the results. Center of pressure (COP) trajectories of 21 trials of a standing healthy subject and 24 trials of a cerebrovascular ...
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In this study, the underlying dynamics of postural control system during quiet standing were investigated. Single-subject (SS) analysis was used as the statistical technique to compare the results. Center of pressure (COP) trajectories of 21 trials of a standing healthy subject and 24 trials of a cerebrovascular attacked (CVA) patient were considered in our analysis. Complexity, dimensionality and stability of postural balance control system were evaluated using the first local minimum of auto mutual information (AMI) function, correlation dimension (Dc) and largest lyapunov exponent (LLE), respectively. The results indicated higher time delays (higher determinism), lower correlation dimension (lower active dynamical degrees of freedom) and lower LLE (increase of local stability) in the postural steadiness time series of the CVA patient in compare with the normal subject. The results showed that these measures not only can be used as pathologic measures to distinguish healthy subjects from CVA patient but also provide us new openings to disclose the postural control mechanism during a quiet standing.
Rehabilitation Engineering
Ali Maleki; Ali Fallah
Volume 2, Issue 2 , June 2008, , Pages 131-140
Abstract
Patients with spinal cord injury in C5/C6 levels are capable of controlling the voluntary movements of the shoulder joints, but some muscles involved in the movement of the elbow joint are paralyzed in these patients. By using FES as well as an appropriate stimulation of the paralyzed muscles, the patients ...
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Patients with spinal cord injury in C5/C6 levels are capable of controlling the voluntary movements of the shoulder joints, but some muscles involved in the movement of the elbow joint are paralyzed in these patients. By using FES as well as an appropriate stimulation of the paralyzed muscles, the patients can be assisted with their essential daily living activities. One of the major problems of using FES for reanimation of the paralyzed arm is to provide voluntary commands for FES control. Kinematic synergy and muscle synergy are two main options in this regard. In this paper, these two command sources were evaluated and compared. Furthermore, a mixed method was proposed, which improves performance. Thus, the EMG and kinematical data during a set of activities of daily living (AOL) were recorded and processed. Precise investigations were carried out in order to determine the appropriate values for high-level neural network controller parameters. Next, six different neural network controller structures were trained by the EMG and/or kinematical data. Using this method, cross correlation between the estimation and measurement for all records was obtained as 94.76% for kinematic synergy and 98.08%, for muscle synergy. In the mixed method, these values were improved to 94.82% and 98.84% respectively. Furthermore, mixed method paved the way to improve the performance of low-level controller with estimating the desired kinematics for the distal joint and desired activity for the paralyzed muscle.
Rehabilitation Engineering
Nima Jamshidi; Mostafa Rostami; Siamak Najarian; Mohammad Bagher Menhaj; Mohammad Saadatnia; Firouz Salami
Volume 2, Issue 1 , June 2008, , Pages 57-64
Abstract
In this research the kinematics parameters derived from ground reaction forces were evaluated to limit the differential diagnoses and measure the degree of disabilities during the walking among neuropathic subjects. 25 neuropathic subjects affected by drop foot and 20 normal subjects were enrolled in ...
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In this research the kinematics parameters derived from ground reaction forces were evaluated to limit the differential diagnoses and measure the degree of disabilities during the walking among neuropathic subjects. 25 neuropathic subjects affected by drop foot and 20 normal subjects were enrolled in the study. There were no differences in the age, weight and height between the patients and normal subjects (p > 0.05). Each subject was tested in average 10±2 times for calculating the kinetic parameters derived from ground reaction forces. Then time parameters and vertical components of force including three extremums of vertical forces, which state various phases in gait, anterior-posterior component of ground reaction force, maximum propulsion force, maximum breaking force during loading stage, maximum propulsion force in the end phase of terminal stance, impact derived from the contact of the patient' foot with floor, loading rate and unloading of vertical forces during the contact' phase of the patient's foot with floor and center of pressure displacement in sole of foot and friction' coefficient between foot and floor were calculated. The results revealed that correlation between the first and second peaks of the anterior-posterior component of ground reaction forces, center of pressure displacement pattern in the sole of foot and time parameters of the vertical forces can be good indexes for differential diagnoses and measuring the degree of disabilities. This research can extend the clinical applications of ground reaction force plate, introduce suitable criteria to limit differential diagnoses and measure the degree of disabilities among the neuropathies. There is a need to replicate this research with more patients and normal subjects to confirm our findings.
