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In this paper, the thickness change of biceps brachii during the fatigue process is continuously monitored using one micro-size single-element ultrasound transducer and analyzed by the echo tracking algorithm. We focus on isometric, 50 % maximum voluntary contraction (MVC) of the elbow. Four subjects participates in the experiment and the result shows that the muscle thickness of biceps brachii continues...
Recently the number of people with swallowing disorders (dysphagia) is increasing. Therefore, efforts are needed to support the swallowing process of dysphagia patients. In order to assist the swallowing process, understanding the initial phase is important. As the first step of development, we analyzed muscle activities related to the initial phase of the swallowing process. In this research, muscle...
Regenerative peripheral-nerve interfaces are a novel method for integrating with the peripheral nervous system. These devices have the potential to isolate and transduce both afferent (sensory) and efferent (motor) neural signals to produce fine control of advanced prosthetics. We have developed a novel regenerative device comprised of microfabricated polyimide electrode threads supported by a hydrogel...
Recently, we proposed a musculoskeletal model to simultaneously predict motion along metacarpophalangeal (MCP) and wrist flexion/extension degrees-of-freedom (DOFs) from surface electromyography (EMG) signals. Since wrist pronation/supination is also functionally important, we extended the musculoskeletal model to simultaneously estimate wrist pronation/supination in addition to wrist and MCP flexion/extension...
In this study, we propose a novel method to explore the relationship between grip force and forearm muscle thickness during isometric contraction. One-directional ultrasound was used to detect the depth of muscle-bone interface. By tracking the movement of this interface, the change of muscle thickness can be calculated. A dynamometer was used to measure force. Three able-bodied subjects were asked...
Understanding how multiple muscles are recruited across a joint has typically been approached from relating muscle activity to resultant forces. New tools are now available to look deeper into a muscle's recruitment by observing groups of single motor units. Identifying changes in the motor unit activity both within a muscle and between muscles the redundancies in motor control can be better understood...
We assessed the impact of different motor unit action potential (MUAP) components in dynamic muscle contractions on decomposition of high-density surface electromyograms (hdEMG). In particular, hypothesis that nontravelling MUAP components, originating from the tendon regions, are less sensitive to changes in geometry of fusiform muscles than travelling MUAP components has been tested on synthetic...
The Helping Hand (HH) system is a novel grasp rehabilitation platform aimed at simplifying the clinical usage of wearable electrode arrays for neuromuscular electrical stimulation (NMES). In a randomized dose-matched, clinical study we evaluate usability and effectiveness of the HH treatment, and of other enriched upper limb rehabilitation treatments, and compare the outcomes. This paper shows the...
A hybrid neuroprosthesis is a device that uses a combination of electric motors and functional electrical stimulation (FES) to provide gait assistance. Its closed-loop control performance can be potentially affected by the presence of electromechanical delay (EMD) during FES. In this paper, a tracking control scheme for a hybrid walking neuroprosthesis that combines electric motor actuation at the...
Three muscle activation estimators: a linear mean-absolute value filter, a recursive Bayesian method, and a kurtosis filter were compared as control approaches for an abstract myoelectric-controlled interface. The linear filter outperformed both the Bayesian and kurtosis methods with respect to participants' overall scores. Despite significantly less efficient trajectories, the Bayesian filter showed...
It is of great significance to detect and predict muscle fatigue for avoiding muscle injury and the negative effects on human-machine interface. This paper presents a novel approach to obtain reliable information about muscle fatigue by analyzing surface electromyography (sEMG) and near-infrared spectroscopy (NIRS) simultaneously. Muscle fatigue was induced via sustained isometric contraction at 50%...
To effectively restore the fine motor functions of the forearm and hand of stroke survivors and patients with traumatic brain injury (TBI), recent studies have proposed an active rehabilitation concept based on the pattern recognition of electromyography (EMG) signals to decode the motor intent of the patients. The results from these studies suggested that pattern recognition of EMG signals associated...
The addition of sensory feedback is expected to greatly enhance the performance of motor neuroprostheses. In the case of stroke or spinal cord injured patients, sensory information can be obtained from electroneurographic (ENG) signals recorded from intact nerves in the non-functioning limb. Here, we aimed to identify sensory information recorded from mixed nerves using a multi-channel cuff electrode...
The corticospinal tract (CST) is one of the descending tracts that carry the forelimb volitional information. Using flexible multi-electrode arrays (MEAs), the CST signals were recorded in rats during active and resting states. The power spectral density (PSD) of CST signals during the active state were notably higher than those observed during resting or anesthesia. Average inter-channel coherences...
Infrared neural stimulation (INS) provides a contact free, high spatial resolution method to regulate neural activities. Due to photothermal effect, neurons which located in the beam path, could be depolarized by infrared light. How to keep the high efficiency of opto-thermal transduction in nerve tissue, and meanwhile increase the photon penetration depth in untargeted tissues is the key question...
Active lower limb exoskeletons can provide assistance to the lower extremities and may drastically improve the walking abilities of millions of individuals with gait impairments. However, most currently available control systems for these devices cannot predict the user's intended movements and have yet to enable walking with seamless transitions. Recent developments in intent recognition for active...
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