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We have constructed a thermal stereoscope utilizing three digital SLR cameras and an infrared camera for rapid surface reconstruction of diabetic foot geometry and temperature distribution. A structured light pattern is projected on to the foot to provide approximately 2500 reconstructed points. The reconstructed point cloud is then fitted to a finite element model, producing root mean squared errors...
Numerous studies have identified arterial stiffening as a strong indicator of cardiovascular pathologies such as hypertension and abdominal aortic aneurysm (AAA). Pulse Wave Imaging (PWI) is a novel, noninvasive ultrasound-based method to quantify regional arterial stiffness by measuring the velocity of the pulse wave that propagates along arterial walls after each left ventricular contraction. The...
Modern passive prosthetic foot/ankles cannot adapt to variations in ground slope. The lack of active adaptation significantly compromises an amputee's balance and stability on uneven terrains. To address this deficit, this paper proposes an ankle prosthesis that uses semi-active damping as a mechanism to provide active slope adaptation. The conceptual ankle prosthesis consists of a modulated damper...
In this study, we present the mechanical design of a prototype of a fully-passive transfemoral prosthesis for normal walking. The conceptual working principle at the basis of the design is inspired by the power flow in human gait, with the main purpose of realizing an energy efficient device. The mechanism is based on three elements, which are responsible of the energetic coupling between the knee...
Foot problems are varied and range from simple disorders through to complex diseases and joint deformities. Wherever possible, the use of insoles, or orthoses, is preferred over surgery. Current insole design techniques are based on static measurements of the foot, despite the fact that orthoses are prevalently used in dynamic conditions while walking or running. This paper presents the design and...
Ankle-foot orthoses (AFOs) ameliorate the impact of impairments to the lower limb neuromuscular motor system that affect gait. Emerging technologies provide a vision for fully powered, untethered AFOs. The portable powered AFO (PPAFO) provides both plantarflexor and dorsiflexor torque assistance via a bi-directional pneumatic rotary actuator. The system uses a portable pneumatic power source (bottle...
A method for estimating step length during level walking using a single inertial measurement unit is proposed. A combination of an optimally filtered direct and reverse integration technique and a velocity update technique for the initial velocity values identification was implemented to reduce the effects of the acceleration signals drift. The method takes advantage of the cyclic nature of gait....
We introduce a method for lower-limb physical rehabilitation by means of a robot that applies preliminary defined forces to a patient's foot while moving it on a preliminary defined trajectory. We developed a special musculoskeletal model that takes into consideration the generated muscle forces of 27 musculotendon actuators and joint stiffness of the leg and allows the calculation of the motion trajectory...
This pilot study aimed at assessing the feasibility and the effectiveness of an electro Electro-tactile Vestibular Substitution System (EVSS) in patients with unilateral vestibular loss under normal and altered somatosensory conditions from the foot and ankle. Four unilateral vestibular-defective patients voluntarily participated in the experiment. They were asked to stand upright as still as possible...
Falls in the elderly are a major problem worldwide, with enormous associated societal costs. Deficits in balance and postural control have long been associated with falls risk in elderly adults. The gold standard for quantitative assessment of human balance in a clinical setting is the force plate which is highly expensive, non-portable and requires specialized personnel to operate. The present study...
We present results from a series of studies that investigated how multimodal mismatches in a virtual environment modified postural response organization. Adaptation of motor commands to functional circumstances is driven directly by error signals. Thus, motor relearning should increase when performing in environments containing sensory mismatch. We hypothesized that kinematics of the response would...
Falls are a prominent problem facing older adults and a common cause of hospitalized injuries. Accurate falls-risk assessment and classification of falls-risk levels will provide useful information for the prevention of future falls. This study presents a triaxial accelerometer (TA) based two-class classifier, which discriminates between multiple fallers and non-multiple fallers, using a directed-routine...
Emerging technologies such as rehabilitation robots (RehaBot) for retraining upper and lower limb functions have shown to carry tremendous potential to improve rehabilitation outcomes. Hstar Technologies is developing a revolutionary rehabilitation robot system enhancing healthcare quality for patients with neurological and muscular injuries or functional impairments. The design of RehaBot is a safe...
The main objective of this work was to evaluate and compare the effects of Functional Electrical Stimulation (FES) therapy in the walking ability and muscle strength studied by electromyography (EMG) analysis between subacute and chronic stroke patients. Eighteen consecutive hemiplegic patients suffering from foot drop were assigned either to subacute or chronic group. Patients of both groups' were...
We present data from cuff electrode recordings from a mixed sensory-/motor nerve as expressed during walking in chronically implanted Göttingen mini-pigs. Our results show that it is possible to filter out residual electromyographic interference and that the energy content of the resulting electroneurographic (ENG) signals modulate clearly with gait. The approach may be used to detect heel strike...
Electrocorticography (ECoG) is an emerging tool to map brain functions in the context of neurosurgical intervention. Previous mapping methods based on the event related power spectrum are prone to noise. To improve the robustness of cortical function mapping, general linear model (GLM), which has been widely used in the analysis of functional magnetic resonance imaging (fMRI) data, is applied to bandpass...
This study performed a concurrent comparison of two walking speed estimation methods using shank- and foot-mounted inertial measurement units (IMUs). Based on the cyclic gait pattern of the stance leg during walking, data was segmented into a series of individual stride cycles. The angular velocity and linear accelerations of the shank and foot over each of these cycles were then integrated to determine...
Ubiquitous analysis of gait is a rapidly emerging field in which research and commercial development has been focused mainly on determining spatio-temporal parameters. In this preliminary research we have developed an algorithm to determine gait metrics from a shoe mounted accelerometer and compared them with concurrent kinematic data. Subjects were tested at different walking speeds as well as an...
In walking analysis, which is one useful method for efficient physical rehabilitation, the ground reaction force, the center of pressure, and the body orientation data are measured during walking. In the past, these data were measured by a 3D motion analysis system consisting of high-speed cameras and force plates, which must be installed in the floor. However, a conventional 3D motion analysis system...
In this paper, we describe an application of hidden Markov models (HMMs) to the problem of time-locating specific events in normal gait movement patterns. The use of HMMs in this paper is mainly related to the opportunity they offer to segment gait data collected at different walking speeds and inclinations of the walking surface. A simple four-state left-right HMM is trained on a dataset of signals...
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