Upper extremity kinetics during walker-assisted gait of knee joint stiffness simulation

Because of various inflammations and fractures of low limbs, the number of patients with knee joint stiffness is increasing. Walkers are commonly prescribed to improve these patients' stability and ambulatory ability. The evaluation on the assisted walking effect has become a hot problem, whose prerequisite is a comprehensive mechanical understanding of the upper extremity force. In order to study the upper extremity kinetics during walker-assisted gait of knee joint stiffness, this paper developed a new method to collect upper extremity kinetics data based on a special-designed walker dynamometer system. Handle reaction vector (HRV) data were collected from 15 healthy right-handed young subjects by simulation experiments for four knee joint stiffness modes. T test and support vector machine (SVM) were used to analyze these HRV data. The results indicated that knee joint stiffness had a great influence on the upper extremity force during the walker-assisted walking. The proposed method is hoped to beneficially influence walker-assisted gait retraining strategies for knee joint stiffness. © 2010 IEEE.published_or_final_versionThe 2010 IEEE International Conference on Virtual Environments Human-Computer Interfaces and Measurement Systems (VECIMS), Taranto, Apulia, Italy, 6-8 September 2010. In Proceedings of the IEEE-VECIMS, 2010, p. 1-

Internal torques of human upper extremity during its optimal motion in vertical plane

In the paper a number of optimal control problems for the motion of the human upper extremity (HUE), for different types of working tasks, are considered. The performance index used in these problems is the integral over the duration of the working task of the sum of the square of the controlling stimuli acting at the joints of the human arm. Under some conditions this performance index can be used for evaluation of the muscles\u27 energy expenditure during human movements. The HUE is simulated by a plane multibody system of rigid masses. The system comprises the three elements with mass and rotatory inertia modelled the upper arm, the forearm and the hand. The controlled motions of the mechanical system are described in terms of joint angles and Cartesian coordinates of the shoulder joint, through the application of Lagrange\u27s equations. The main aim of the study is an investigation of the interaction between the gravity forces and the internal torques acting at the joints during goal-directed extremal motions of the HUE. The analysis of the internal torques, energetic and viscoelastic characteristics of the shoulder, the elbow and the wrist joints for the exstremal controlled motions of the human arm under the external load acting on the hand has been done

Observation of Amounts of Movement Practice Provided during Stroke Rehabilitation

Objective To investigate how much movement practice occurred during stroke rehabilitation, and what factors might influence doses of practice provided. Design Observational survey of stroke therapy sessions. Setting Seven inpatient and outpatient rehabilitation sites. Participants We observed a convenience sample of 312 physical and occupational therapy sessions for people with stroke. Interventions Not applicable. Main Outcome Measures We recorded numbers of repetitions in specific movement categories and data on potential modifying factors (patient age, side affected, time since stroke, FIM item scores, years of therapist experience). Descriptive statistics were used to characterize amounts of practice. Correlation and regression analyses were used to determine whether potential factors were related to the amount of practice in the 2 important categories of upper extremity functional movements and gait steps. Results Practice of task-specific, functional upper extremity movements occurred in 51% of the sessions that addressed upper limb rehabilitation, and the average number of repetitions/session was 32 (95% confidence interval [CI]=20–44). Practice of gait occurred in 84% of sessions that addressed lower limb rehabilitation and the average number of gait steps/session was 357 (95% CI=296–418). None of the potential factors listed accounted for significant variance in the amount of practice in either of these 2 categories. Conclusions The amount of practice provided during poststroke rehabilitation is small compared with animal models. It is possible that current doses of task-specific practice during rehabilitation are not adequate to drive the neural reorganization needed to promote function poststroke optimally

Characterization of Laser-Resistant Port Wine Stain Blood Vessels Using In Vivo Reflectance Confocal Microscopy.

Background and objectivesPort wine stain (PWS) is a congenital vascular malformation of the human skin. Laser is the treatment of choice for PWS. Laser-resistant PWS is one crucial factor accounting for inadequate treatment outcome, which needs to be fully characterized. This study aims to quantitatively characterize the morphology of laser-resistant PWS blood vessels in the upper papillary dermis using in vivo reflectance confocal microscopy (RCM).Study design/materials and methodsA total of 42 PWS subjects receiving laser treatment from August 2016 through July 2018 were enrolled into this study. Thirty-three subjects had facial PWS; nine had extremity PWS. All subject's PWS received multiplex 585/1,064 nm laser treatment. RCM images were taken before and after treatment. The density, diameter, blood flow, and depth of PWS blood vessels were analyzed.ResultsWe found 44.4% PWS on the extremities (four out of nine subjects) were laser-resistant, which was significantly higher (P < 0.001) when compared with those PWS on the face (15.2%, 5 out of 33 subjects). The laser-resistant facial PWS blood vessels had significantly higher blood flow (1.35 ± 0.26 U vs. 0.89 ± 0.22 U, P < 0.001), larger blood vessel diameters (109.60 ± 18.24 µm vs. 84.36 ± 24.04 µm, P = 0.033) and were located deeper in the skin (106.01 ± 13.87 µm vs. 87.82 ± 12.57 µm, P < 0.001) in the skin when compared with laser-responsive PWS on the face. The average PWS blood vessel density (17.01 ± 4.63/mm2 vs. 16.61 ± 4.44/mm2 , P = 0.857) was not correlated to the laser resistance.ConclusionsLaser-resistant PWS blood vessels had significantly higher blood flow, larger diameters, and were located deeper in the skin. RCM can be a valuable tool for a prognostic evaluation on laser-resistant lesions before treatment, thereby providing guidance for tailored laser treatment protocols, which may improve the therapeutic outcome. The limitations for this study include relative small sample size and acquisitions of different blood vessels before and after 2 months of treatment. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc

New control strategies for neuroprosthetic systems

The availability of techniques to artificially excite paralyzed muscles opens enormous potential for restoring both upper and lower extremity movements with\ud neuroprostheses. Neuroprostheses must stimulate muscle, and control and regulate the artificial movements produced. Control methods to accomplish these tasks include feedforward (open-loop), feedback, and adaptive control. Feedforward control requires a great deal of information about the biomechanical behavior of the limb. For the upper extremity, an artificial motor program was developed to provide such movement program input to a neuroprosthesis. In lower extremity control, one group achieved their best results by attempting to meet naturally perceived gait objectives rather than to follow an exact joint angle trajectory. Adaptive feedforward control, as implemented in the cycleto-cycle controller, gave good compensation for the gradual decrease in performance observed with open-loop control. A neural network controller was able to control its system to customize stimulation parameters in order to generate a desired output trajectory in a given individual and to maintain tracking performance in the presence of muscle fatigue. The authors believe that practical FNS control systems must\ud exhibit many of these features of neurophysiological systems

Biomechanics

Biomechanics is a vast discipline within the field of Biomedical Engineering. It explores the underlying mechanics of how biological and physiological systems move. It encompasses important clinical applications to address questions related to medicine using engineering mechanics principles. Biomechanics includes interdisciplinary concepts from engineers, physicians, therapists, biologists, physicists, and mathematicians. Through their collaborative efforts, biomechanics research is ever changing and expanding, explaining new mechanisms and principles for dynamic human systems. Biomechanics is used to describe how the human body moves, walks, and breathes, in addition to how it responds to injury and rehabilitation. Advanced biomechanical modeling methods, such as inverse dynamics, finite element analysis, and musculoskeletal modeling are used to simulate and investigate human situations in regard to movement and injury. Biomechanical technologies are progressing to answer contemporary medical questions. The future of biomechanics is dependent on interdisciplinary research efforts and the education of tomorrow’s scientists

Biomechanical Model for Evaluation of Pediatric Upper Extremity Joint Dynamics During Wheelchair Mobility

Pediatric manual wheelchair users (MWU) require high joint demands on their upper extremity (UE) during wheelchair mobility, leading them to be at risk of developing pain and pathology. Studies have examined UE biomechanics during wheelchair mobility in the adult population; however, current methods for evaluating UE joint dynamics of pediatric MWU are limited. An inverse dynamics model is proposed to characterize three-dimensional UE joint kinematics and kinetics during pediatric wheelchair mobility using a SmartWheel instrumented handrim system. The bilateral model comprises thorax, clavicle, scapula, upper arm, forearm, and hand segments and includes the sternoclavicular, acromioclavicular, glenohumeral, elbow and wrist joints. A single 17 year-old male with a C7 spinal cord injury (SCI) was evaluated while propelling his wheelchair across a 15-meter walkway. The subject exhibited wrist extension angles up to 60°, large elbow ranges of motion and peak glenohumeral joint forces up to 10% body weight. Statistically significant asymmetry of the wrist, elbow, glenohumeral and acromioclavicular joints was detected by the model. As demonstrated, the custom bilateral UE pediatric model may provide considerable quantitative insight into UE joint dynamics to improve wheelchair prescription, training, rehabilitation and long-term care of children with orthopedic disabilities. Further research is warranted to evaluate pediatric wheelchair mobility in a larger population of children with SCI to investigate correlations to pain, function and transitional changes to adulthood

Virtual reality based upper extremity stroke rehabilitation system.

Some studies suggest that the use of Virtual Reality technologies as an assistive technology in combination with conventional therapies can achieve improved results in post stroke rehabilitation. Despite the wealth of ongoing research applied to trying to build a virtual reality based system for upper extremity rehabilitation, there still exists a strong need for a training platform that would provide whole arm rehabilitation. In order to be practical such a system should ideally be low cost (affordable or inexpensive for a common individual or household) and involve minimal therapist involvement. This research outlines some of the applications of virtual reality that have undergone clinical trials with patients suffering from upper extremity functional motor deficits. Furthermore, this thesis presents the design, development, implementation and feasibility testing of a Virtual Reality-based Upper Extremity Stroke Rehabilitation System. Motion sensing technology has been used to capture the real time movement data of the upper extremity and a virtual reality glove has been used to track the flexion/extension of the fingers. A virtual room has been designed with an avatar of the human arm to allow a variety of training tasks to be accomplished. An interface has been established to incorporate the real time data from the hardware to a virtual scene running on a PC. Three different training scenes depicting a real world scenario have been designed. These have been used to analyze the motion patterns of the users while executing the tasks in the virtual environment simulation. A usability study with the healthy volunteers performing the training tasks have been undertaken to study the ease of use, ease of learning and improved motivation in the virtual environment. Moreover this system costing approximately 2725 pounds would provide home based rehabilitation of the whole arm augmenting conventional therapy on a positive level. Statistical analysis of the data and the evaluation studies with the self report methodologies suggests the feasibility of the system for post stroke rehabilitation in home environment

Biomechanics of Pediatric Manual Wheelchair Mobility

Currently, there is limited research of the biomechanics of pediatric manual wheelchair mobility. Specifically, the biomechanics of functional tasks and their relationship to joint pain and health is not well understood. To contribute to this knowledge gap, a quantitative rehabilitation approach was applied for characterizing upper extremity biomechanics of manual wheelchair mobility in children and adolescents during propulsion, starting, and stopping tasks. A Vicon motion analysis system captured movement, while a SmartWheel simultaneously collected three-dimensional forces and moments occurring at the handrim. A custom pediatric inverse dynamics model was used to evaluate three-dimensional upper extremity joint motions, forces, and moments of 14 children with spinal cord injury (SCI) during the functional tasks. Additionally, pain and health-related quality of life outcomes were assessed. This research found that joint demands are significantly different amongst functional tasks, with greatest demands placed on the shoulder during the starting task. Propulsion was significantly different from starting and stopping at all joints. We identified multiple stroke patterns used by the children, some of which are not standard in adults. One subject reported average daily pain, which was minimal. Lower than normal physical health and higher than normal mental health was found in this population. It can be concluded that functional tasks should be considered in addition to propulsion for rehabilitation and SCI treatment planning. This research provides wheelchair users and clinicians with a comprehensive, biomechanical, mobility assessment approach for wheelchair prescription, training, and long-term care of children with SCI