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Author

Carolina Silveira

Other affiliations: University of Coimbra
Bio: Carolina Silveira is an academic researcher from Newcastle University. The author has contributed to research in topics: Sciatic nerve & Sensory system. The author has an hindex of 4, co-authored 9 publications receiving 46 citations. Previous affiliations of Carolina Silveira include University of Coimbra.

Papers
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Journal ArticleDOI
TL;DR: Two detailed 3D multibody foot-ankle models generated based on CT scans using a semi-automatic tool are described, one with 15DOF and the other with 8DOF, presenting realistic results.
Abstract: Multibody simulations of human motion require representative models of the anatomical structures. A model that captures the complexity of the foot is still lacking. In the present work, two detailed 3D multibody foot-ankle models generated based on CT scans using a semi-automatic tool are described. The proposed models consists of five rigid segments (talus, calcaneus, midfoot, forefoot and toes), connected by five joints (ankle, subtalar, midtarsal, tarsometatarsal and metatarsophalangeal), one with 15DOF and the other with 8DOF. The calculated kinematics of both models were evaluated using gait trials and compared against literature, both presenting realistic results. An inverse dynamic analysis was performed for the 8DOF model, again presenting feasible dynamic results.

25 citations

Journal ArticleDOI
TL;DR: The results indicate that increasing the complexity of a nerve cuff may only be advantageous if the nerve cuff is to be implanted distally, where the nerve has begun to divide into individual fascicles.
Abstract: Objective. Recording of neural signals from intact peripheral nerves in patients with spinal cord injury or stroke survivors offers the possibility for the development of closed-loop sensorimotor prostheses. Nerve cuffs have been found to provide stable recordings from peripheral nerves for prolonged periods of time. However, questions remain over the design and positioning of nerve cuffs such that the separability of neural data recorded from the peripheral nerves is improved. Approach. Afferent electroneurographic (ENG) signals were recorded with nerve cuffs placed on the sciatic nerve of rats in response to various mechanical stimuli to the hindpaw. The mean absolute value of the signal was extracted and input to a classifier. The performance of the classifier was evaluated under two conditions: (1) when information from either a 3- or 16-channel cuff was used; (2) when information was available from a cuff placed either distally or proximally along the nerve. Main results. We show that both 3- and 16-channel cuffs were able to separate afferent ENG signals with an accuracy greater than chance. The highest classification scores were achieved when the classifier was fed with information obtained from a 16-channel cuff placed distally. While the 16-channel cuff always outperformed the 3-channel cuff, the difference in performance was increased when the 16-channel cuff was placed distally rather than proximally on the nerve. Significance. The results indicate that increasing the complexity of a nerve cuff may only be advantageous if the nerve cuff is to be implanted distally, where the nerve has begun to divide into individual fascicles.

24 citations

Journal ArticleDOI
19 Aug 2019
TL;DR: Experiments showed that it took 8 ms for the sensory fibers to completely recover from a conditioning stimulus, regardless of the relative position of the electrodes used for stimulation, demonstrating that the electrodes on the cuff cannot be considered independent.
Abstract: Multi-channel nerve cuff electrode arrays can provide sensory feedback to prosthesis users. To develop efficacious stimulation protocols, an understanding of the impact that spatio-temporal patterned stimulation can have on the response of sensory fibers is crucial. We used experimental and modelling methods to investigate the response of nerve fibers to paired-pulse stimulation. Nerve cuff electrode arrays were implanted for stimulation of the sciatic nerves of rats and the sensory compound action potentials were recorded from the L4 dorsal root. A model of the nerve cuff electrode array and sciatic nerve was also developed. The experimental and modelling results were compared. Experiments showed that it took 8 ms for the sensory fibers to completely recover from a conditioning stimulus, regardless of the relative position of the electrodes used for stimulation. The results demonstrate that the electrodes on the cuff cannot be considered independent. Additionally, at 120% of the threshold, there is a large overlap in the fibers that were activated by the different electrodes. If a stimulus paradigm considered the electrodes as independent, stimuli from the different electrodes would need to be interleaved, and the intervals between the stimuli should be greater than 8 ms.

10 citations

Proceedings ArticleDOI
01 May 2017
TL;DR: The results show that classification of nociceptive and proprioceptive stimuli is feasible, with cross validation errors of less than 10%.
Abstract: 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. ENG afferent signals were recorded in response to mechanical stimulation of the foot corresponding to three different functional types of sensory stimuli, namely: nociception, proprioception and touch. Offine digital signal processing was used to extract features for use as inputs for classification. A quadratic support vector machine was used to classify the data and the five fold cross validation error was measured. The results show that classification of nociceptive and proprioceptive stimuli is feasible, with cross validation errors of less than 10%. However, further work is needed to determine whether the touch information can be extracted more reliably from these recordings.

4 citations

Journal ArticleDOI
13 Aug 2020
TL;DR: A flexible, transversal intraneural tungsten:titanium electrode array for acute studies is introduced and it is shown that the stimulation of peripheral nerves with this electrode array is possible and that more than half of the electrode contacts can yield a stimulation selectivity index of 0.75 or higher at low stimulation currents.
Abstract: The development of hardware for neural interfacing remains a technical challenge. We introduce a flexible, transversal intraneural tungsten:titanium electrode array for acute studies. We characterize the electrochemical properties of this new combination of tungsten and titanium using cyclic voltammetry and electrochemical impedance spectroscopy. With an in-vivo rodent study, we show that the stimulation of peripheral nerves with this electrode array is possible and that more than half of the electrode contacts can yield a stimulation selectivity index of 0.75 or higher at low stimulation currents. This feasibility study paves the way for the development of future cost-effective and easy-to-fabricate neural interfacing electrodes for acute settings, which ultimately can inform the development of technologies that enable bi-directional communication with the human nervous system.

2 citations


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TL;DR: You could look for impressive publication by the title of Basic Biomechanics Of The Musculoskeletal System by panamabustickets.com Studio to aid you obtain originality about the book you check out.
Abstract: You could look for impressive publication by the title of Basic Biomechanics Of The Musculoskeletal System by panamabustickets.com Studio Presently, you can conveniently to review every publication by online and download without spending great deals time for seeing book stores. Your best publication's title is here! You can discover your book to aid you obtain originality about the book you check out. Locate them in zip, txt, word, rar, kindle, ppt, and pdf report. basic biomechanics mccc basic biomechanics “it is important when learning about how the body moves (kinesiology) to also learn about the forces placed on the body that cause the movement.” lippert, p93

532 citations

Journal ArticleDOI
TL;DR: Fundamental and practical principles guiding PNI design are reviewed, followed by an updated and critical account of existing PNI designs and strategies, and a brief survey of in vitro and in vivo PNI characterization methods.

69 citations

Journal ArticleDOI
TL;DR: The importance of foot muscles in controlling plantar pressure distribution and internal stresses is confirmed by the improved accuracy in the estimation of the peak pressures obtained with the inclusion of intrinsic and extrinsic muscle forces.

31 citations

Journal ArticleDOI
TL;DR: An MRI-based morphological fitting methodology is proposed for the personalised definition of the tibiotalar and the subtalar joint axes during gait, and its application to characterise the ankle kinematics in patients affected by Juvenile Idiopathic Arthritis is investigated.

25 citations