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This study developed a method of discriminating real-time motion from electromyogram (EMG) signals. We previously proposed a real-time motion discrimination method using hyper-sphere models that discriminated five motions (open, grasp, pinching, wrist extension, and wrist flexion) above 90% and quickly learned EMG signals. Our method prevents elbow motions from interfering with hand motion discrimination...
Low back pain (LBP) is a leading cause of disability. The population with low back pain is continuously growing in the recent years. This study tries to distinguish LBP patients with healthy subjects by using the objective surface electromyography (SEMG) as a quantitative score for clinical evaluations. There are 26 healthy and 26 low back pain subjects who involved in this research. They lifted different...
A model that simulates surface electromyogram (sEMG) signal of m. Tibialis Anterior has been developed and tested. This has a firing rate equation that is based on experimental findings. It also has a recruitment threshold that is based on observed statistical distribution. Importantly, it has considered both, slow and fast type which has been distinguished based on their conduction velocity. This...
This paper aims to describe the optimal autoregressive order of varying-length electromyograms for myopathic subjects. Epochs of electromyography signals are modeled as outputs of autoregressive systems, for orders varying from 1 to 100. The optimal order to represent each epoch is chosen by the minimum description length criterion. Probability density functions are fitted to the histograms of the...
Regenerative peripheral nerve interfaces (RPNIs) are for signal transfer between peripheral nerves inside the body to controllers for motorized prosthetics external to the body. Within the residual limb of an amputee, surgical construction of a RPNI connects a remaining peripheral nerve and spare muscle. Nerve signals become concentrated within the RPNI. Currently metal electrodes implanted on the...
Human emotion recognition (HER) allows the assessment of an affective state of a subject. Until recently, such emotional states were described in terms of discrete emotions, like happiness or contempt. In order to cover a high range of emotions, researchers in the field have introduced different dimensional spaces for emotion description that allow the characterization of affective states in terms...
This paper presents a platform to study the relationship between upper limb kinematic and biopotential measurements. The platform comprises of a haptic joystick, biopotential acquisition systems and 3D rendered virtual tasks that require user interaction. The haptic joystick, named TeeR, reproduces the pronation-supination and flexion-extension movements of the human arm, which are directly mapped...
Ankle joint with spasticity and/or contracture can severely affect mobility and independence of stroke survivors. Due to that, the Achilles tendon(AT) is affected. In this paper, we aim to study changes of AT properties via proprioceptive neuromuscular facilitation (PNF) treatment. A robotic ankle-foot rehabilitation system has been proposed, which consists of a robotic ankle-foot platform and a graphic...
Ptosis of the eyelids is a common condition with a myriad of causes. Its management depends on the underlying cause, which can be challenging to diagnose in some cases. Current diagnosis methods include serum antibodies, tensilon test, and electromyography (EMG). Each has its own set of limitations such as invasiveness and lack of sensitivity. To overcome these limitations, we have developed a Portable...
Adapting limb mechanics in a task and environment dependent manner is one component of human motor control. Joint mechanics have been extensively studied under static postural conditions, but less so under time-varying movement conditions. The limited studies that have investigated joint mechanics during movement, have found a drop in joint stiffness during movement, however the source of this decrease...
This paper describes a novel method for the identification of time-varying ankle joint dynamic stiffness during large passive movements. The method estimates a linear parameter varying parallel-cascade (LPV-PC) model of joint stiffness consisting of two pathways: (a) an LPV impulse response function (IRF) for intrinsic mechanics and (b) an LPV Hammerstein cascade with time-varying static nonlinearity...
During physiological gait, humans continuously modulate their knee stiffness, depending on the demands of the activity and the terrain. A similar functionality could be provided by modern actuators in transfemoral prosthesis. However, quantitative data on how knee stiffness is modulated during physiological gait is still missing. This is likely due to the experimental difficulties associated with...
Motor cortical local field potentials (LFPs) have been successfully used to decode both kinematics and kinetics of arm movement. For future clinically viable prostheses, however, brain activity decoders will have to generalize well under a wide spectrum of behavioral conditions. This property has not yet been demonstrated clearly. Here, we provide evidence for the first time, that an LFP-based electromyogram...
Although great advances have been made in the design and control of lower extremity prostheses, walking on different terrains, such as ramps or stairs, and transitioning between these terrains remains a major challenge for the field. In order to generalize biomimetic behaviour of active lower-limb prostheses top-down volitional control is required but has until recently been deemed unfeasible due...
Despite modern technological advances, the most widely available prostheses provide little functional recovery beyond basic grasping. Although sophisticated upper extremity prostheses are available, optimal prosthetic interfaces which give patients high-fidelity control of these artificial limbs are limited. We have developed a novel Regenerative Peripheral Nerve Interface (RPNI), which consists of...
Generation of torque around a joint usually involves the activation of several agonist muscles and may also involve the co-activation of antagonist muscles. Therefore, a valid model for the dynamic relation between surface EMG (an indirect measured of the muscle's neural input) and the torque should take the form of a Multiple-Input/Single-Output (MISO) system to account for the contributions of the...
The rectification of EMG signals is a preprocessing method widely used for inferring neural connectivity by coherence analysis. The assumption for the use of this non-linear operator is that it enhances the neural information in the signal, i.e. the motor unit spike trains. However, because of non-linearity, it is difficult to predict the effect of rectification on the EMG power spectrum. In this...
Surface electromyogram (SEMG) measurements employing a bipolar configuration are generally used to evaluate muscle fatigue. However, the changes in the SEMGs accompanying fatigue cannot be detected in some cases. We evaluated the differences in the detection of muscle fatigue during isometric and dynamic contraction between monopolar and bipolar configurations for measuring SEMGs. The results illustrated...
Neuroprosthetic devices that interface with the nervous system to restore functional motor activity offer a viable alternative to nerve regeneration, especially in proximal nerve injuries like brachial plexus injuries where muscle atrophy may set in before nerve re-innervation occurs. Prior studies have used control signals from muscle or cortical activity. However, nerve signals are preferred in...
In this paper we present a series of design directions for the development of affordable, compliant, modular, underactuated robot fingers, that can be used as prostheses by amputees that suffer from various partial hand amputations (index to pinky fingers are considered). Our design is based on parametric models that have been derived from hand anthropometry studies. Various interfaces have been considered...
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