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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...
Patients with paralysis will one day rely on clinically-available brain-machine interfaces (BMI) to facilitate activities of daily living. As such, the ability to generate dexterous reaching movements remains a prime target of BMI algorithms research. The Bayesian approach to BMI algorithms requires a statistical model to describe reaching movements. To date, available models have either required...
Recent advances in the design and development of retinal implants have made these devices a promising therapeutic strategy for restoring sight to the blind. Over the last decade a plethora of studies have investigated the responses of the retinal ganglion cells (RGCs) to electrical stimulation under a variety of stimulus configurations. Similar to the RGCs, the amacrine cells also survive in large...
We have previously shown that augmentative vibrotactile feedback can improve performance of a virtual object manipulation task using the finger. Here we studied the effects of vibrotactile feedback using instead electromyographic (EMG) control of object manipulation in N=6 healthy participants. Results showed that users were able to increase performance on an object manipulation task via EMG control...
Implantable interfaces are essential components of vestibular neural prostheses. They interface the biological system with electrical stimulation that is used to restore transfer of vestibular information. Regarding the anatomical situation special 3D structures are required. In this paper, the design and the manufacturing process of a novel 3D hybrid microelectrode structure as interface to the human...
The effectiveness of retinal prosthetics will depend on their ability to elicit patterns of neural activity that can be recognized by the visual cortex. While conventional short-duration pulses activate retinal neurons effectively, many nearby neurons are thought to respond similarly to a given pulse train — a situation that is non-physiological. Use of pulse trains delivered at rates > 1000 pulses...
An epiretinal prosthesis aims to restore functional vision by stimulating electrically the retinal ganglion cells (RGCs) in patients affected by photoreceptor degenerative diseases, such as age-related macular degeneration (AMD) and retinitis pigmentosa (RP). During retinal degeneration, photoreceptor death is followed by pronounced remodeling and rewiring of inner retinal cells. Despite these changes,...
In this research, inductive telemetric structure for retinal prosthesis was developed based on Liquid Crystal Polymers. For power and data transmission into the polymer-based retinal implant which is conformable to eye surface, the designed coil was thermo-formed into convex shape. The geometric parameters of the coil were optimized using finite element method (FEM) simulations for maximizing coupling...
Brain-machine interfaces (BMIs) aim to help disabled patients by translating neural signals from the brain into control signals for guiding prosthetic arms, computer cursors, and other assistive devices. Animal models are central to the development of these systems and have helped enable the successful translation of the first generation of BMIs. As we move toward next-generation systems, we face...
A balance control model was applied to interpret how subjects with a severe vestibular loss (VL) used vibrotactile information from a balance prosthesis to enhance balance control. Experimental data were from 5 VL subjects standing with eyes closed and responding to continuous pseudorandom surface tilts of the stance platform. Results showed that vibrotactile feedback information reduced sway at frequencies...
Vibrotactile feedback about body position and velocity has been shown to be effective at reducing low frequency body sway (below about 0.5 Hz) in response to balance perturbations while standing. However, current devices cause an undesirable increase in high frequency body sway. In addition, unlike other sensory prostheses such as hearing aids, which are fine-tuned to the user, current vibrotactile...
This study investigated whether training with realtime prosthetic biofeedback (BF) of trunk sway induces a carry-over improvement in balance control once BF is removed. 12 healthy older adults and 7 uncompensated unilateral vestibular loss patients were tested. All participants performed a battery of 14 balance and gait tasks (pre-test) upon their initial lab visit during which trunk angular sway...
An integrated vestibular-cochlear implant can be rapidly prototyped and clinically tested by modifying an existing modern cochlear implant. The modifications include addition of gyroscope sensors and reallocation of several electrodes that are normally used for auditory nerve stimulation to the semicircular canals, while sharing the external DSP processor and the internal receiver/stimulator. This...
More than two thirds of valve replacement operations performed each year used mechanical heart valve. These valves are subject to complications such: pannus and/or thrombus formation. One other potential complication is a malfunction in one of the valve leaflets. It is then important to develop parameters that will allow a non-invasive diagnosis of such valve malfunction. In the present study, we...
In this paper we present surface electromyo-graphic (EMG) data collected from 16 channels on five unimpaired subjects and one transradial amputee performing 12 individual finger movements and a rest class. EMG were processed using a traditional Time Domain feature-set and classifiers: a Linear Discriminant Analysis (LDA) a k-Nearest Neighbors (k-NN) and Support Vector Machine (SVM). Using continuous...
In order to improve the quality of life of persons who lost their limb due to an accident or a sickness, many myoelectric artificial arms have been proposed. To control the motion of the elbow joint of the myoelectric arm, the EMG signals of the biceps brachii and the triceps brachii muscles are frequently used as input signals. However, since both muscles are the biarticular muscles between the shoulder...
In transradial amputees, the muscles in the residual forearm naturally employed by the unimpaired for flexing/extending the hand fingers, are the most appropriate targets, for multi-fingered prostheses control. However, once the prosthetic socket is manufactured and fitted on the residual forearm, the recorded EMG might not be originated only by the intention of performing finger movements, but also...
Vestibular prostheses are regarded as a promising tool to restore lost sensation in patients with vestibular disorders. These prostheses often electrically stimulate the vestibular nerve and stimulation efficacy is evaluated by measuring the vestibulo-ocular reflex (VOR). However, eye movement recording as intuitive metric of vestibular functionality is difficult to obtain outside the laboratory environment,...
During the development of a neural prosthesis, various ethical aspects have to be considered. These range from the basic design of the prosthesis and manufacturing of the various components and the system using biocompatible materials to extensive in vitro and in vivo testing and investigations in the animal model, before taking the final step and going to human trials. As medical systems, neural...
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