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depth electrodes

Ahmet Cakir, Robert F Labadie, M Geraldine Zuniga, Benoit M Dawant, Jack H Noble
OBJECTIVE: To investigate the accuracy of rigid cochlear models in measuring intra-cochlear positions of cochlear implant (CI) electrodes. PATIENTS: Ninety three adults who had undergone CI and pre- and postoperative computed tomographic (CT) imaging. MAIN OUTCOME MEASURES: Seven rigid models of cochlear anatomy were constructed using micro-CTs of cochlear specimens. Using each of the seven models, the position of each electrode in each of the 98 ears in our dataset was measured as its depth along the length of the cochlea, its distance to the basilar membrane, and its distance to the modiolus...
October 14, 2016: Otology & Neurotology
Juul Verberne, Frank Risis, Luke Campbell, Scott Chambers, Stephen O'Leary
HYPOTHESIS: Scala tympani morphology influences the insertion dynamics and intra-scalar position of straight electrode arrays. BACKGROUND: Hearing preservation is the goal of cochlear implantation with current thin straight electrode arrays. These hug the lateral wall, facilitating full, atraumatic insertions. However, most studies still report some postoperative hearing loss. This study explores the influence of scala tympani morphology on array position relative to the basilar membrane and its possible contribution to postoperative hearing loss...
October 12, 2016: Otology & Neurotology
Maja Svrakic, J Thomas Roland, Sean O McMenomey, Mario A Svirsky
OBJECTIVE: To describe our initial operative experience and hearing preservation results with the Advanced Bionics (AB) Mid Scala Electrode (MSE). STUDY DESIGN: Retrospective review. SETTING: Tertiary referral center. PATIENTS: Sixty-three MSE implants in pediatric and adult patients were compared with age- and sex-matched 1j electrode implants from the same manufacturer. All patients were severe to profoundly deaf. INTERVENTION: Cochlear implantation with either the AB 1j electrode or the AB MSE...
October 12, 2016: Otology & Neurotology
Nayan Chanauria, Vishal Bharmauria, Lyes Bachatene, Sarah Cattan, Jean Rouat, Stéphane Molotchnikoff
V1 is fundamentally grouped into columns that descend from layer II-III to layer V-VI. Neurons inherent to visual cortex are capable of adapting to changes in the incoming stimuli that drive the cortical plasticity. A principle feature called orientation selectivity can be altered by the presentation of non-optimal stimulus called 'adapter'. When triggered, LGN cells impinge upon layer IV and further relay the information to deeper layers via layer II-III. Using different adaptation protocols, neuronal plasticity can be investigated...
October 14, 2016: European Journal of Neuroscience
Mani Saignavongs, Carolina Ciumas, Mathilde Petton, Romain Bouet, Sébastien Boulogne, Sylvain Rheims, David W Carmichael, Jean-Philippe Lachaux, Philippe Ryvlin
Recent studies have shown that it is feasible to record simultaneously intracerebral EEG (icEEG) and functional magnetic resonance imaging (fMRI) in patients with epilepsy. While it has mainly been used to explore the hemodynamic changes associated with epileptic spikes, this approach could also provide new insight into human cognition. However, the first step is to ensure that cognitive EEG components, that have lower amplitudes than epileptic spikes, can be appropriately detected under fMRI. We compared the high frequency activities (HFA, 50-150[Formula: see text]Hz) elicited by a reading task in icEEG-only and subsequent icEEG-fMRI in the same patients ([Formula: see text]), implanted with depth electrodes...
August 22, 2016: International Journal of Neural Systems
Chengjun Huang, Xiang Chen, Shuai Cao, Xu Zhang
OBJECTIVE: Some skeletal muscles can be subdivided into smaller segments called muscle-tendon units (MTUs). The purpose of this paper is to propose a framework to locate the active region of the corresponding MTUs within a single skeletal muscle and to analyze the activation level varieties of different MTUs during a dynamic motion task. APPROACH: Biceps brachii and gastrocnemius were selected as targeted muscles and three dynamic motion tasks were designed and studied...
October 5, 2016: Journal of Neural Engineering
Chiara Pastori, Stefano Francione, Federica Pelle, Marco de Curtis, Vadym Gnatkovsky
A quantitative method was developed to map cortical areas responsive to cognitive tasks during intracerebral stereo-EEG recording sessions in drug-resistant patients candidate for epilepsy surgery. Frequency power changes were evaluated with a computer-assisted analysis in 7 patients during phonemic fluency tasks. All patients were right-handed and were explored with depth electrodes in the dominant frontal lobe. We demonstrate that fluency tasks enhance beta-gamma frequencies and reduce background activities in language network regions of the dominant hemisphere...
September 26, 2016: Brain and Language
Meng Zhou, Joshua Catanach, Joshua Gomez, Stephanie Richins, Shuguang Deng
Nanoporous carbon was synthesized from microalgae as a promising electrode material for electric double layer capacitors due to its large specific surface area and controllable pore structures. The pore textural properties of the algae-derived-carbon (ADC) samples were measured by N2 adsorption and desorption at 77 K. The performance of the activated carbon (AC) as supercapacitor electrodes was determined by the cyclic voltammetry and galvanostatic charge/discharge tests. The effect of the nanoporous carbon structure on capacitance was demonstrated by calculating the contributions of micropores and mesopores toward capacitance...
September 28, 2016: ACS Applied Materials & Interfaces
Hannes O Tiedt, Felicitas Ehlen, Lea K Krugel, Andreas Horn, Andrea A Kühn, Fabian Klostermann
Subcortical functions for language capacities are poorly defined, but may be investigated in the context of deep brain stimulation. Here, we studied event-related potentials recorded from electrodes in the subthalamic nucleus (STN) and the thalamic ventral intermediate nucleus (VIM) together with surface-EEG. Participants completed a lexical decision task (LDT), which required the differentiation of acoustically presented words from pseudo-words by button press. Target stimuli were preceded by prime-words. In recordings from VIM, a slow potential shift apparent at the lower electrode contacts persisted during target stimulus presentation (equally for words and pseudo-words)...
September 20, 2016: Human Brain Mapping
Chunyan Liu, Ruihua Zhang, Guojun Zhang, Tao Yu, Junli Tai, Wei Du, Liping Li, Yuping Wang
OBJECTIVE: In some cases of single focus epilepsy, conventional video electroencephalography (EEG) cannot reveal the epileptogenic focus even when intracranial electrodes are used. Here, we tested whether analyzing high frequency oscillations (HFOs) can be used to determine the ictal onset zone in suspected bitemporal epilepsy and improve seizure outcome. METHODS: We prospectively studied 13 patients with refractory temporal seizures who were treated over a 4-year period and underwent bilateral placement of intracranial electrodes...
September 5, 2016: Epilepsy Research
Francis Pete X Creighton, Xiying Guan, Steve Park, Ioannis John Kymissis, Hideko Heidi Nakajima, Elizabeth S Olson
OBJECTIVE: To validate an intracochlear piezoelectric sensor for its ability to detect intracochlear pressure and function as a microphone for a fully implantable cochlear implant. METHODS: A polyvinylidene fluoride (PVDF) piezoelectric pressure sensor was inserted into a human fresh cadaveric round window at varying depths. An external sound pressure stimulus was applied to the external auditory canal (EAC). EAC pressure, stapes velocity, and piezoelectric sensor voltage output were recorded...
September 14, 2016: Otology & Neurotology
Sung Il Park, Il Jung Kim, Shin Jae Lee, Min Woo Shin, Won Sun Shin, Yong Eun Chung, Gyoung Min Kim, Man Deuk Kim, Jong Yun Won, Do Yun Lee, Jin Sub Choi, Kwang-Hyub Han
OBJECTIVE: To evaluate the feasibility of angled cool-tip electrode for radiofrequency ablation of small superficial subcapsular liver tumors abutting abdominal wall, in order to traverse normal liver parenchyma, and thereby, obtain favorable configuration of ablation margin. MATERIALS AND METHODS: In this study, we retrospectively analyzed 15 small superficial subcapsular liver tumors abutting abdominal wall in 15 patients, treated with radiofrequency ablation from March 2013 to June 2015 using a cool-tip electrode manually modified to create 25-35° angle at the junction between exposed and insulated segments...
September 2016: Korean Journal of Radiology: Official Journal of the Korean Radiological Society
Marlene Mittmann, Arneborg Ernst, Philipp Mittmann, Ingo Todt
CONCLUSION: Over time, a homogenous increase in intracochlear pressure was seen in every experiment. Significant reductions in terms of amplitude variation and insertion depth were observed over time, using the one-point-supported insertion method. The frequency of peaks between the thirds was significantly lower when using the two-points-supported insertion method. OBJECTIVES: The preservation of residual hearing and minimization of intracochlear trauma are two of the major goals in modern cochlear implantation (CI) surgery...
August 30, 2016: Acta Oto-laryngologica
Spela Kos, Tanja Blagus, Maja Cemazar, Ursa Lampreht Tratar, Monika Stimac, Lara Prosen, Tanja Dolinsek, Urska Kamensek, Simona Kranjc, Lars Steinstraesser, Gaëlle Vandermeulen, Véronique Préat, Gregor Sersa
Skin is an attractive target for gene electrotransfer. It consists of different cell types that can be transfected, leading to various responses to gene electrotransfer. We demonstrate that these responses could be controlled by selecting the appropriate electrotransfer parameters. Specifically, the application of low or high electric pulses, applied by multi-electrode array, provided the possibility to control the depth of the transfection in the skin, the duration and the level of gene expression, as well as the local or systemic distribution of the transgene...
2016: Molecular Therapy. Nucleic Acids
Itzhak Fried
Deep brain stimulation has been successfully used in treatment of motor symptoms of Parkinson's disease and other movement disorders. In a recent multi-center prospectively randomized study, deep brain stimulation of the fornix was administered in order to ameliorate the cognitive symptoms and clinical course of Alzheimer's disease (AD). The study points to the possibility of modest slowing of the cognitive decline in AD in a subset of patients older than 65, while at the same time highlights the risk of stimulation in exacerbation of this decline in younger patients...
September 6, 2016: Journal of Alzheimer's Disease: JAD
T Jouen, R Clément, H Henine, C Chaumont, B Vincent, J Tournebize
In France, 10 % of total arable land is equipped with subsurface drainage systems, to control winter and spring waterlogging due to a temporary perched water table. Most of these systems were installed in the1980s and have aged since then and may now need maintenance. Sometimes, the location of the systems is known, but the standard situation in France is that the original as-built master sketches are no longer available. Performance assessment of drainage systems and curative actions are complicated since drain location is unknown...
August 26, 2016: Environmental Science and Pollution Research International
Jessica L Durham, Altug S Poyraz, Esther S Takeuchi, Amy C Marschilok, Kenneth J Takeuchi
Electric energy storage devices such as batteries are complex systems comprised of a variety of materials with each playing separate yet interactive roles, complicated by length scale interactions occurring from the molecular to the mesoscale. Thus, addressing specific battery issues such as functional capacity requires a comprehensive perspective initiating with atomic level concepts. For example, the electroactive materials which contribute to the functional capacity in a battery comprise approximately 30% or less of the total device mass...
September 20, 2016: Accounts of Chemical Research
Jason Pile, Alex D Sweeney, Shaun Kumar, Nabil Simaan, George B Wanna
OBJECTIVES: To test the hypothesis that bipolar electrical impedance measurements in perimodiolar cochlear implants (CIs) may be used to differentiate between perimodiolar insertion technique favoring proximity to the modiolus or lateral wall. STUDY DESIGN AND METHODS: Bipolar impedances are a measure of electrical resistance between pairs of electrode contacts in a CI. Stimulation is through biphasic pulses at fixed frequency. Impedance measurements were made in real time through sequential sampling of electrode pairs...
August 24, 2016: Laryngoscope
Jorge de Abajo, Raquel Manrique-Huarte, Ignacio Sanhueza, Laura Alvarez-Gómez, Cristina Zulueta-Santos, Diego Calavia, Fernando Ramírez, Manuel Manrique
OBJECTIVES: The objectives of this study were to evaluate the effect of reimplanting a cochlear implant electrode in animal normal-hearing cochlea to propose measures that may prevent cochlear injury and, given its close phylogenetic proximity to humans, to evaluate the macaque as a model for electroacoustic stimulation. DESIGN: Simultaneous, bilateral surgical procedures in a group of 5 normal-hearing specimens (Macaca fascicularis) took place in a total of 10 ears...
August 22, 2016: Ear and Hearing
Manuel R Mercier, Stephan Bickel, Pierre Megevand, David M Groppe, Charles E Schroeder, Ashesh D Mehta, Fred A Lado
While there is a strong interest in meso-scale field potential recording using intracranial electroencephalography with penetrating depth electrodes (i.e. stereotactic EEG or S-EEG) in humans, the signal recorded in the white matter remains ignored. White matter is generally considered electrically neutral and often included in the reference montage. Moreover re-referencing electrophysiological data is a critical preprocessing choice that could drastically impact signal content and consequently the results of any given analysis...
August 20, 2016: NeuroImage
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