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Literatura académica sobre el tema "Electrical evoked potentials"

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Publicado: 11 de marzo de 2023

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Artículos de revistas sobre el tema "Electrical evoked potentials"

Sasaki, Tatsuya, Kyouichi Suzuki, Masato Matsumoto, Taku Sato, Namio Kodama y Keiko Yago. "Origin of surface potentials evoked by electrical stimulation of oculomotor nerves: are they related to electrooculographic or electromyographic events?" Journal of Neurosurgery 97, n.º 4 (octubre de 2002): 941–44. http://dx.doi.org/10.3171/jns.2002.97.4.0941.

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Object. Evoked potentials elicited by electrical stimulation of the oculomotor nerve and recorded from surface electrodes placed on the skin around the eyeball reportedly originate in the eye and are represented on electrooculograms. Because evoked potentials recorded from surface electrodes are extremely similar to those of extraocular muscles, which are represented on electromyograms, the authors investigated the true origin of these potentials. Methods. Evoked potentials elicited by electrical stimulation of the canine oculomotor nerve were recorded from surface electrodes placed on the skin around the eyeball. A thread sutured to the center of the cornea was pulled and the potentials that were evoked during the resultant eye movement were recorded. These potentials were confirmed to originate in the eye and to be represented on electrooculograms because their waveforms were unaffected by the administration of muscle relaxant. To eliminate the influence of this source, the retina, a main origin of standing potentials of the eyeball, was removed. This resulted in the disappearance of electrooculography (EOG) waves elicited by eye movement. Surface potentials elicited by oculomotor nerve stimulation were the same before and after removal of the retina. Again the oculomotor nerve was electrically stimulated and electromyography (EMG) response of the extraocular muscles was recorded at the same time that potentials were recorded from the surface electrodes. In their peak latencies, amplitudes, and waveforms, the evoked potentials obtained from surface electrodes were almost identical to EMG responses of extraocular muscles. Conclusions. Evoked potentials elicited by electrical stimulation of the oculomotor nerves and obtained from surface electrodes originated from EMG responses of extraocular muscles. These evoked potentials do not derive from the eye.

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Schwindt, Peter C. y Wayne E. Crill. "Synaptically Evoked Dendritic Action Potentials in Rat Neocortical Pyramidal Neurons". Journal of Neurophysiology 79, n.º 5 (1 de mayo de 1998): 2432–46. http://dx.doi.org/10.1152/jn.1998.79.5.2432.

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Schwindt, Peter C. and Wayne E. Crill. Synaptically evoked dendritic action potentials in rat neocortical pyramidal neurons. J. Neurophysiol. 79: 2432–2446, 1998. In a previous study iontophoresis of glutamate on the apical dendrite of layer 5 pyramidal neurons from rat neocortex was used to identify sites at which dendritic depolarization evoked small, prolonged Ca2+ spikes and/or low-threshold Na+ spikes recorded by an intracellular microelectrode in the soma. These spikes were identified as originating in the dendrite. Here we evoke similar dendritic responses by electrical stimulation of presynaptic elements near the tip of the iontophoretic electrode with the use of a second extracellular electrode. In 9 of 12 recorded cells, electrically evoked excitatory postsynaptic potentials (EPSPs) above a minimum size triggered all-or-none postsynaptic responses similar to those evoked by dendritic glutamate iontophoresis at the same site. Both the synaptically evoked and the iontophoretically evoked depolarizations were abolished reversably by blockade of glutamate receptors. In all recorded cells, the combination of iontophoresis and an EPSP, each of which was subthreshold for the dendritic spike when given alone, evoked a dendritic spike similar to that evoked by a sufficiently large iontophoresis. In one cell tested, dendritic spikes could be evoked by the summation of two independent subthreshold EPSPs evoked by stimulation at two different locations. We conclude that the dendritic spikes are not unique to the use of glutamate iontophoresis because similar spikes can be evoked by EPSPs. We discuss the implications of these results for synaptic integration and for the interpretation of recorded synaptic potentials.

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Perrier, Jean-François, Boris Lamotte D'Incamps, Nezha Kouchtir-Devanne, Léna Jami y Daniel Zytnicki. "Effects on Peroneal Motoneurons of Cutaneous Afferents Activated by Mechanical or Electrical Stimulations". Journal of Neurophysiology 83, n.º 6 (1 de junio de 2000): 3209–16. http://dx.doi.org/10.1152/jn.2000.83.6.3209.

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The postsynaptic potentials elicited in peroneal motoneurons by either mechanical stimulation of cutaneous areas innervated by the superficial peroneal nerve (SP) or repetitive electrical stimulation of SP were compared in anesthetized cats. After denervation of the foot sparing only the territory of SP terminal branches, reproducible mechanical stimulations were applied by pressure on the plantar surface of the toes via a plastic disk attached to a servo-length device, causing a mild compression of toes. This stimulus evoked small but consistent postsynaptic potentials in every peroneal motoneuron. Weak stimuli elicited only excitatory postsynaptic potentials (EPSPs), whereas increase in stimulation strength allowed distinction of three patterns of response. In about one half of the sample, mechanical stimulation or trains of 20/s electric pulses at strengths up to six times the threshold of the most excitable fibers in the nerve evoked only EPSPs. Responses to electrical stimulation appeared with 3–7 ms central latencies, suggesting oligosynaptic pathways. In another, smaller fraction of the sample, inhibitory postsynaptic potentials (IPSPs) appeared with an increase of stimulation strength, and the last fraction showed a mixed pattern of excitation and inhibition. In 24 of 32 motoneurons where electrical and mechanical effects could be compared, the responses were similar, and in 6 others, they changed from pure excitation on mechanical stimulation to mixed on electrical stimulation. With both kinds of stimulation, stronger stimulations were required to evoke inhibitory postsynaptic potentials (IPSPs), which appeared at longer central latencies than EPSPs, indicating longer interneuronal pathways. The similarity of responses to mechanical and electrical stimulation in a majority of peroneal motoneurons suggests that the effects of commonly used electrical stimulation are good predictors of the responses of peroneal motoneurons to natural skin stimulation. The different types of responses to cutaneous afferents from SP territory reflect a complex connectivity allowing modulations of cutaneous reflex responses in various postures and gaits.

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Oberle, Joachim, Gregor Antoniadis, Erich Kast y Hans-Peter Richter. "Evaluation of Traumatic Cervical Nerve Root Injuries by Intraoperative Evoked Potentials". Neurosurgery 51, n.º 5 (1 de noviembre de 2002): 1182–90. http://dx.doi.org/10.1097/00006123-200211000-00012.

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Abstract OBJECTIVE To evaluate intraoperative evoked potentials as a diagnostic tool in traumatic brachial plexus injuries. METHODS Thirteen patients with traumatic brachial plexus injuries were investigated by intradural nerve root inspection (n = 28 roots) via cervical hemilaminectomy to assess or rule out nerve root avulsion from the spinal cord. Two to 8 weeks later, evoked potentials from neck and scalp were recorded after direct electrical nerve root stimulation close to the vertebral foramen during operative brachial plexus repair via an anterior (supraclavicular and infraclavicular) approach. Recordings were performed without and after full muscle relaxation. RESULTS There was a clear relationship between the state of the root as documented by intradural root inspection and the result of intraoperative recording of evoked potentials: the absence of evoked muscle action potentials from neck muscles demonstrated a 100% sensitivity for anterior root lesions, whereas sensory evoked potentials from the scalp demonstrated a 100% sensitivity for posterior root lesions. Moreover, roots could be identified with preserved continuity that did not conduct, suggesting a nerve lesion in continuity. CONCLUSION Intraoperative evoked muscle action potentials and sensory evoked potentials after electrical nerve root stimulation allow selective functional evaluation of anterior and posterior nerve roots in patients with traumatic brachial plexus injuries. The high sensitivity and reliability of this test obviate the need for additional diagnostic surgery.

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Zhang, Jianmei, Victor Z. Han, Johannes Meek y Curtis C. Bell. "Granular Cells of the Mormyrid Electrosensory Lobe and Postsynaptic Control Over Presynaptic Spike Occurrence and Amplitude Through an Electrical Synapse". Journal of Neurophysiology 97, n.º 3 (marzo de 2007): 2191–203. http://dx.doi.org/10.1152/jn.01262.2006.

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Primary afferent fibers from the electroreceptors of mormyrid electric fish use a latency code to signal the intensity of electrical current evoked by the fish's own electric organ discharge (EOD). The afferent fibers terminate centrally in the deep and superficial granular layers of the electrosensory lobe with morphologically mixed chemical–electrical synapses. The granular cells in these layers seem to decode afferent latency through an interaction between primary afferent input and a corollary discharge input associated with the EOD motor command. We studied the physiology of deep and superficial granular cells in a slice preparation with whole cell patch recording and electrical stimulation of afferent fibers. Afferent stimulation evoked large all-or-none electrical excitatory postsynaptic potentials (EPSPs) and large all or none GABAergic inhibitory postsynaptic potentials (IPSPs) in both superficial and deep granular cells. The amplitudes of the electrical EPSPs depended on postsynaptic membrane potential, with maximum amplitudes at membrane potentials between −65 and −110 mV. Hyperpolarization beyond this level resulted in either the abrupt disappearance of EPSPs, a step-like reduction to a smaller EPSP, or a graded reduction in EPSP amplitude. Depolarization to membrane potentials lower than that yielding a maximum caused a linear decrease in EPSP amplitude, with EPSP amplitude reaching 0 mV at potentials between −55 and −40 mV. We suggest that the dependence of EPSP size on postsynaptic membrane potential is caused by close linkage of pre- and postsynaptic membrane potentials through a high-conductance gap junction. We also suggest that this dependence may result in functionally important nonlinear interactions between synaptic inputs.

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Wang, Guo-Du, Xi-Yu Wang, Sumei Liu, Yun Xia, Fei Zou, Meihua Qu, Bradley J. Needleman, Dean J. Mikami y Jackie D. Wood. "β-Nicotinamide adenine dinucleotide acts at prejunctional adenosine A1 receptors to suppress inhibitory musculomotor neurotransmission in guinea pig colon and human jejunum". American Journal of Physiology-Gastrointestinal and Liver Physiology 308, n.º 11 (1 de junio de 2015): G955—G963. http://dx.doi.org/10.1152/ajpgi.00430.2014.

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Intracellular microelectrodes were used to record neurogenic inhibitory junction potentials in the intestinal circular muscle coat. Electrical field stimulation was used to stimulate intramural neurons and evoke contraction of the smooth musculature. Exposure to β-nicotinamide adenine dinucleotide (β-NAD) did not alter smooth muscle membrane potential in guinea pig colon or human jejunum. ATP, ADP, β-NAD, and adenosine, as well as the purinergic P2Y1 receptor antagonists MRS 2179 and MRS 2500 and the adenosine A1 receptor agonist 2-chloro- N6-cyclopentyladenosine, each suppressed inhibitory junction potentials in guinea pig and human preparations. β-NAD suppressed contractile force of twitch-like contractions evoked by electrical field stimulation in guinea pig and human preparations. P2Y1 receptor antagonists did not reverse this action. Stimulation of adenosine A1 receptors with 2-chloro- N6-cyclopentyladenosine suppressed the force of twitch contractions evoked by electrical field stimulation in like manner to the action of β-NAD. Blockade of adenosine A1 receptors with 8-cyclopentyl-1,3-dipropylxanthine suppressed the inhibitory action of β-NAD on the force of electrically evoked contractions. The results do not support an inhibitory neurotransmitter role for β-NAD at intestinal neuromuscular junctions. The data suggest that β-NAD is a ligand for the adenosine A1 receptor subtype expressed by neurons in the enteric nervous system. The influence of β-NAD on intestinal motility emerges from adenosine A1 receptor-mediated suppression of neurotransmitter release at inhibitory neuromuscular junctions.

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Sato, Masanori, Namio Kodama, Tatsuya Sasaki y Mamoru Ohta. "Olfactory evoked potentials: experimental and clinical studies". Journal of Neurosurgery 85, n.º 6 (diciembre de 1996): 1122–26. http://dx.doi.org/10.3171/jns.1996.85.6.1122.

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✓ Olfactory evoked potentials (OEPs), obtained by electrical stimulation of the olfactory mucosa, were recorded in dogs and humans to develop an objective method for evaluating olfactory functions. In dogs, OEPs were recorded from the olfactory tract and the scalp. The latency of the first negative peak was approximately 40 msec. A response was not obtained after stimulation of the nasal mucosa and disappeared after sectioning of the olfactory nerve. With increasing frequencies of repetitive stimulation, the amplitude was reduced, suggesting that the response was synaptically mediated. These results demonstrate that evoked potentials from the olfactory tract and the scalp following electrical stimulation of the olfactory mucosa originate specifically from the olfactory system. In humans, a stimulating electrode with a soft catheter was fixed on the olfactory mucosa. The OEPs from the olfactory tract, recorded with a negative peak of approximately 27 msec, had similar characteristics to OEPs found in dogs. The OEPs from the olfactory tract in humans also originate specifically from the olfactory system. The authors postulate that OEPs obtained by electrical stimulation of the olfactory mucosa may prove useful for intraoperative monitoring of olfactory functions.

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KIKUCHI, Yasuhiro, Tatsuya SASAKI, Masato MATSUMOTO, Tomoyoshi OIKAWA, Takeshi ITAKURA y Namio KODAMA. "Optic Nerve Evoked Potentials Elicited by Electrical Stimulation". Neurologia medico-chirurgica 45, n.º 7 (2005): 349–55. http://dx.doi.org/10.2176/nmc.45.349.

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Yu, Dong-Zhen y Shan-Kai Yin. "R035: Electrical-Evoked Field Potentials within Vestibular Nuclei". Otolaryngology–Head and Neck Surgery 135, n.º 2_suppl (agosto de 2006): P116. http://dx.doi.org/10.1016/j.otohns.2006.06.787.

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Dorfman, L. J., M. Gaynon, J. Ceranski, A. A. Louis y J. E. Howard. "Visual electrical evoked potentials: Evaluation of ocular injuries". Neurology 37, n.º 1 (1 de enero de 1987): 123. http://dx.doi.org/10.1212/wnl.37.1.123.

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Tesis sobre el tema "Electrical evoked potentials"

Hocking, Christopher Anthony y Christopher Hocking@med monash edu au. "Brain electrical activity and automization". Swinburne University of Technology, 1999. http://adt.lib.swin.edu.au./public/adt-VSWT20051021.110535.

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Novices and experts show distinct differences in the performance of many tasks. Experts may perform a task quickly and accurately with seemingly little attention or effort, whilst novices will perform the same task more slowly and with great effort. The transition from novice to expert performance occurs only after extended practice and has been conceptualized as a transition from controlled to automatic processing, and has been modeled as a reduction in attention or cognitive resources. Alternatively, based on findings relating to learning in the domain of number arithmetic, it has also been modeled as a transition from an algorithmic, or computationally-based process, to the use of memory retrieval. However, relatively few studies have investigated the changes in brain activity associated with such a transition. In this study, the Steady-State Probe Topography technique was used to investigate differences in the topography of the Steady-State Visual Evoked Potential (SSVEP) between an unpracticed and a well-practiced analogue of number arithmetic, Alphabet arithmetic. Subjects showed decreases in response time with practice that followed a power law and were suggestive of automatization. During initial, unpracticed performance of the task, processing of the Alphabet Arithmetic equations was characterised by increased SSVEP amplitude and decreased latency in frontal regions, whilst after extended practice, performance was characterised by reduced SSVEP amplitude and increased latency. It is suggested that the frontal activity during the initial, unpracticed stage of the task implicates a role for working memory, whilst the amplitude decrease and latency increase observed in the well-practiced task may reflect a reduction in excitation, consistent with ideas of an improvement in brain efficiency, and possibly an increase in inhibitory processes.

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Rennie, Christopher. "Modeling the large-scale electrical activity of the brain". Connect to full text, 2001. http://hdl.handle.net/2123/816.

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Thesis (Ph. D.)--University of Sydney, 2001.
Includes published articles. Title from title screen (viewed Apr. 24, 2008). Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the School of Physics, Faculty of Science. Includes bibliography. Also available in print form.

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Ciorciari, Joseph y jciorciari@swin edu au. "Topograhic distribution of human brain electrical activity associated with schizophrenia". Swinburne University of Technology, 1999. http://adt.lib.swin.edu.au./public/adt-VSWT20050610.152013.

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A literature review of the schizophrenia brain electrophysiology was undertaken with specific emphasis placed on the topographical distribution of evoked potentials (EPs). The outcomes of this review suggests that schizophrenia brain electrophysiology, demonstrate some differences, but with a variability reflective of the symptom heterogeneity. The literature associated with the use of attentional tasks while recording EPs, tended to demonstrate some consistency. The methodological issues associated with the EEG and EP recordings may also account for this variability. An evoked potential technique, which has been demonstrated to be sensitive to the changes in cognitive processes associated with attention, is the Steady State Probe Topography (SSPT) technique. The SSPT is a combination of both the Steady State Visual Evoked Potential (SSVEP) and the Probe-ERP paradigm. This technique allows the SSVEP to be measured continuously, is relatively insensitive to artifact, and can display the topographic distribution of the SSVEP measures during the attentional task. The technique employs the use of a sixty-four channel EEG recording system. This consists of a multichannel electrode helmet; multichannel amplifier/filter, task presentation computer and a computer controlled data acquisition system. Software was also developed to analyse the recorded brain electrical activity to produce the SSVEP magnitude and phase versus time series for each electrode site. The topographic distribution of the SSVEP measures associated with specific events during attentional tasks could also be displayed. At the time of the pilot study, this technique had not been applied previously to the study of schizophrenia and therefore warranted further study. Two separate studies are reported; an investigative pilot study and a chronic group study. The pilot SSVEP and schizophrenia study was designed to examine the changes in the SSVEP and its topography, during the performance of a number of attentional or activation tasks to examine the possibility of hypofrontality. The tasks selected for the study were those previously used for the examination of hypofrontality with metabolic imaging techniques; the Continuous Performance Task (CPT) and the Wisconsin Card Sort (WCS). The SSVEP was elicited by a superimposed 13Hz flicker on the visual field, while subjects performed computerised versions of the neuropsychological tasks. Topographical maps of the SSVEP magnitude distribution were then interpolated and displayed as an animated sequence synchronised with particular events occurring during the tasks. In comparison to the male control group, male schizophrenic patients exhibited differences in the SSVEP topography for all tasks, possibly reflecting the deficits in behavioural indices. Overall, the findings indicated that the technique demonstrated some merit for further examination of frontal SSVEP topography in schizophrenia. In a larger study of twenty chronic schizophrenia patients, the frontal topographical distribution of the SSVEP was examined. The earlier pilot study finding of reduced frontal SSVEP amplitude was replicated. The issue of hypofrontality in schizophrenia was applied as a possible interpretation.

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Takeyama, Hirofumi. "Human entorhinal cortex electrical stimulation evoked short-latency potentials in the broad neocortical regions: Evidence from cortico-cortical evoked potential recordings". Kyoto University, 2020. http://hdl.handle.net/2433/253148.

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Yamao, Yukihiro. "Intraoperative dorsal language network mapping by using single-pulse electrical stimulation". Kyoto University, 2014. http://hdl.handle.net/2433/188692.

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Tanguenza, Arianna. "Somatosensory Evoked Potentials following somatotopic and non somatotopic upper limb electrical stimulation". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019.

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Uno dei principali problemi riscontrati nell’utilizzo di una protesi di arto superiore è la mancanza di feedback sensoriale, che riduce il controllo di movimenti e forza applicata, limitando la percezione della protesi come parte del proprio corpo (embodiment). La stimolazione non invasiva dei nervi mediano e ulnare rappresenta un possibile strumento per la restituzione di feedback somatotopico, cioè percepito sull’arto (mano) fantasma, in alternativa alle procedure invasive che hanno già permesso di ottenere buone performance su alcuni amputati. I correlati neurali della stimolazione del nervo mediano sono stati ampiamente riportati in letteratura, mentre pochi sono i casi in cui si analizzano gli effetti della stimolazione del nervo ulnare o della stimolazione simultanea di due nervi (bipolare). È inoltre necessario tenere in considerazione gli effetti della stimolazione non somatotopica, non riferita alla mano ma localizzata sul sito di stimolazione, in quanto si tratta di un fenomeno “di disturbo” presente anche nella stimolazione somatotopica. Questo elaborato si pone l’obiettivo di caratterizzare i correlati neurali in seguito alla stimolazione elettrica transcutanea (TENS) dei nervi dell’arto superiore. Undici soggetti sono stati sottoposti alla stimolazione dei nervi mediano e ulnare, concorrente alla registrazione del segnale elettroencefalografico (EEG). In un piccolo gruppo è stata effettuata anche la caratterizzazione della stimolazione non somatotopica. I Potenziali Evocati Somatosensoriali (SEPs) sono stati confrontati per ogni condizione di stimolazione. Nell’elaborato vengono discusse le differenze riscontrate e vengono analizzati in dettaglio gli effetti della stimolazione somatotopica, considerata come migliore soluzione per il feedback non invasivo.

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Reeve, Edward M. "Brain electrical activity assessment of concurrent music and event-related potential cognitive tasks /". The Ohio State University, 1986. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487323583620978.

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Gale, Alan Ian. "Signal processing and modelling of coritcal evoked potentials for feature extraction". Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/42593.

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Johnson, Mark Ian. "Factors influencing the analgesic effects and clinical efficacy of transcutaneous electrical nerve stimulation (TENS)". Thesis, University of Newcastle Upon Tyne, 1991. http://hdl.handle.net/10443/539.

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Transcutaneous electrical nerve stimulation (TENS) is a simple, non-invasive technique used in the control of chronic pain. Despite the success of TENS and its continued use for over twenty years, some patients either fail to respond or show only a partial response. Furthermore some patients respond initially to TENS but then become tolerant to its analgesic effects. The reasons for poor response to TENS are unknown; different clinics report widely differing success rates, and information on long-term efficacy is sparse. Furthermore, TENS is still administered on an empirical basis in which the patient determines by trial and error the most appropriate stimulator settings (i. e. electrical characteristics of TENS) to treat his or her particular pain. It is impossible to predict whether an individual patient will respond to TENS or which stimulator settings will be optimal. In an attempt to elucidate these problems, the clinical, electrophysiological, neuropharmacological, psychological and sociological factors that influence the analgesic effects and clinical efficacy of TENS have been examined in this thesis. Three clinical studies were performed. The first (Study 2.1) reviewed the use of TENS since its introduction to Newcastle Pain Relief Clinic in 1979. It was found that 1582 patients have been given a trial of TENS of which 927 (58.6%) continue to use a stimulator on a long-term basis (Study 2.1). The clinical use of TENS by 179 of these patients was examined in-depth (Study 2.2). Although previous literature suggests that TENS is most efficacious for pains of neurogenic (neuropathic) origin, it was found that any type of pain may respond. No relationships were found to exist between the electrical characteristics of TENS (i. e. stimulator settings) used by patients during TENS treatment and the cause and site of pain. However, patients utilised specific pulse frequencies and patterns and consistently used these settings on subsequent treatment sessions (Study 2.3). These clinical studies showed that in this population, 41.4% of patients failed to respond to TENS and half using TENS on a long-term basis achieved less than 50% relief of pain. Thus, a systematic investigation to determine optimal electrical characteristics of TENS was performed. Three experiments were undertaken to examine separately the analgesic effects of different electrical characteristics of TENS (pulse frequency, pulse pattern and stimulation mode) on cold-pressor pain in healthy subjects. The effects of a range of Long Abstract pulse frequencies (10Hz to 160Hz) applied to produce a 'strong but comfortable' electrical paraesthesia within the painful site were measured (Exp. 3.1). It was found that frequencies between 20-80Hz were most effective. However, no differential effects were observed between a range of pulse patterns (continuous, burst, modulation, random; Exp. 3.2). When TENS was applied in burst mode at an intensity sufficient to produce phasic muscle twitches at a site distant yet myotomally related to the site of pain (acupuncture-like TENS) a powerful analgesic effect was observed during and post-stimulation (Exp. 3.3). It is suggested that continuous mode stimulation at 80Hz, producing a 'strong but comfortable' electrical paraesthesia within the painful site, should be the primary TENS treatment choice in the clinic but that in selected cases AL-TENS may be more effective. A number of improvements in stimulator design are suggested. Further experiments were aimed at elucidating the mechanism of TENS effects by investigating the influence of TENS on electrophysiological and neuropharmacological variables. It was found that TENS reduced peak-to-peak amplitudes of the late waveform components (N1P2) of somatosensory evoked potentials (Exp. 4.1) and increased alpha, beta and theta activity of spontaneous EEG in healthy subjects (Exp. 4.2) and/or pain patients (Exp. 4.3). As TENS produced changes in SEPs elicited from non-painful stimuli, and also changes in spontaneous EEG in pain-free subjects, it is suggested that the effects of TENS may be due in part to changes in sensory processing at several levels in the nervous system which may not specific for the perception of pain. The surprising finding that TENS increased peripheral circulating met-enkephalin in chronic pain patients was attributed to a stress-like release although this observation remains to be confirmed using a larger population sample (Exp. 5.1). The results of these experiments suggest that baseline electrophysiological and neuropharmacological variables may be important determinants of individual response to TENS. Thus, a prospective investigation was undertaken on 29 patients who were undergoing a trial of TENS to control chronic pain, in an attempt to identify predictors of patient response. Patient response to TENS was related to baseline SEP amplitudes and spontaneous EEG but was not related to biochemical, psycho-social, personality or pain related factors (Exp. 6.1). Thus, patients with small peak-to-peak amplitudes of the SEP, and low power spectrum of spontaneous EEG showed poor response to TENS (Exp. 6.1). It is suggested that an individual's intrinsic central response pattern to external stimuli may influence response to TENS.

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Yurtkolesi, Mustafa. "Imaging Electrical Conductivity Distribution Of The Human Head Using Evoked Fields And Potentials". Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609828/index.pdf.

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In the human brain, electrical activities are created due to the body functions. These electrical activities create potentials and magnetic fields which can be monitored elec- trically (Electroencephalography - EEG) or magnetically (Magnetoencephalography - MEG). Electrical activities in human brain are usually modeled by electrical dipoles. The purpose of Electro-magnetic source imaging (EMSI) is to determine the position, orientation and strength of dipoles. The first stage of EMSI is to model the human head numerically. In this study, The Finite Element Method (FEM) is chosen to han- dle anisotropy in the brain. The second stage of EMSI is to solve the potentials and magnetic fields for an assumed dipole configuration (forward problem). Realistic con- ductivity distribution of human head is required for more accurate forward problem solutions. However, to our knowledge, conductivity distribution for an individual has not been computed yet. The aim of this thesis study is to investigate the feasibility of a new approach to update the initially assumed conductivity distribution by using the evoked potentials and fields acquired during EMSI studies. This will increase the success of source localization problem, since more realistic conductivity distribution of the head will be used in the forward problem. This new method can also be used as a new imaging modality, especially for inhomogeneities where the conductivity value deviates. In this thesis study, to investigate the sensitivity of measurements to conductivity perturbations, a FEM based sensitivity matrix approach is used. The performance of the proposed method is tested using three different head models - homogeneous spherical, 4 layer concentric sphere and realistic head model. For spherical head models rectangular grids are preferred in the middle and curved elements are used nearby the head boundary. For realistic cases, head models are developed using uniform grids. Tissue boundary information is obtained by applying segmentation algorithms to the Magnetic Resonance (MR) images. A paralel computer cluster is employed to assess the feasibility of this new approach. PETSc library is used for forward problem calculations and linear system solutions. The performance of this novel approach depends on many factors such as the head model, number of dipoles and sensors used in the calculation, noise in the measure- ments, etc. In this thesis study, a number of simulations are performed to investigate the effects of each of these parameters. Increase in the number of elements in the head model leads to the increase in the number of unknows for linear system solu- tions. Then, accuracy of the solution is improved with increased number of dipoles or sensors. The performance of the adopted approach is investigated using noise-free measurements as well as noisy measurements. For EEG, measurement noise decreases the accuracy of the approach. For MEG, the effect of measurement noise is more pronounced and may lead to a larger error in tissue conductivity calculation.

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Más fuentes

Libros sobre el tema "Electrical evoked potentials"

H, Duffy Frank, ed. Topographic mapping of brain electrical activity. Boston: Butterworths, 1986.

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H, Duffy Frank, ed. Topographic mapping of brain electrical activity. Boston: Butterworth, 1986.

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International Symposium on Clinical Neurophysiological Aspects of Psychiatric Conditions (7th 1985 Philadelphia, Pa.). Brain electrical potentials and psychopathology: Proceedings of the VII International Symposium on Clinical Neurophysiological Aspects of Psychiatric Conditions, held September 7-8, 1985, in Philadelphia, Pennsylvania. Editado por Shagass Charles 1920-, Josiassen Richard C y Roemer Richard A. New York: Elsevier, 1986.

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S, Gevins A. y Rémond Antoine, eds. Methods of analysis of brain electrical and magnetic signals. Amsterdam: Elsevier, 1987.

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Houlden, David Allen. A comparison of descending evoked potentials and muscle responses after transcranial magnetic stimulation and skull base electrical stimulation in awake human subjects. Ottawa: National Library of Canada = Bibliothèque nationale du Canada, 1997.

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F, Grandori, Hoke M y Romani G. L, eds. Auditory evoked magnetic fields and electric potentials. Basel: Karger, 1990.

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1947-, Levy Walter J., Chicago Neurosurgical Center y Symposium on Transcranial Magnetic Stimulation and the Motor Evoked Potential (1989 : Chicago, Ill.), eds. Magnetic motor stimulation: Basic principles and clinical experience. Amsterdam: Elsevier, 1991.

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Magnetic stimulation of the human nervous system. Oxford: Oxford University Press, 1999.

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Hans, Lüders, ed. Deep brain stimulation and epilepsy. London: Martin Dunitz, 2004.

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E, Cullington Helen, ed. Cochlear implants: Objective measures. London: Whurr Publishers, 2003.

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Capítulos de libros sobre el tema "Electrical evoked potentials"

Duffy, F. H. "Topographic Mapping of Brain Electrical Activity: Clinical Applications and Issues". En Topographic Brain Mapping of EEG and Evoked Potentials, 19–52. Berlin, Heidelberg: Springer Berlin Heidelberg, 1989. http://dx.doi.org/10.1007/978-3-642-72658-3_3.

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Honoki, Hitomi, Trongmun Jiralerspong, Fumiya Sato y Jun Ishikawa. "Experimental Evaluation of Steady State Visual Evoked Potentials for Brain Machine Interface". En Lecture Notes in Electrical Engineering, 267–77. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-69814-4_27.

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Lim, C. L., C. Rennie, C. Yiannikas, E. Gordon, G. J. Sloggett, R. J.-M. Grognard y A. D. Seagar. "Short Latency Median Nerve Somatosensory Evoked Magnetic Fields and Electrical Potentials". En Advances in Biomagnetism, 153–56. Boston, MA: Springer US, 1989. http://dx.doi.org/10.1007/978-1-4613-0581-1_25.

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Thielen, J., P. Marsman, J. Farquhar y P. Desain. "Re(con)volution: Accurate Response Prediction for Broad-Band Evoked Potentials-Based Brain Computer Interfaces". En SpringerBriefs in Electrical and Computer Engineering, 35–42. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-64373-1_4.

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Islam, Md Nahidul, Norizam Sulaiman, Mamunur Rashid, Mahfuzah Mustafa y Md Jahid Hasan. "Auditory Evoked Potentials (AEPs) Response Classification: A Fast Fourier Transform (FFT) and Support Vector Machine (SVM) Approach". En Lecture Notes in Electrical Engineering, 539–49. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-2406-3_41.

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Faig, J., M. Tegenthoff y J. P. Malin. "Magnetically Evoked Corticofacial Potentials of Orbicularis Oculi Muscle Conditioned by the Electrical Blink Reflex". En Brain-Stem Localization and Function, 219–24. Berlin, Heidelberg: Springer Berlin Heidelberg, 1993. http://dx.doi.org/10.1007/978-3-642-78172-8_25.

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Kajihara, H., Y. Yamauchi y M. Nozawa. "Comparison of spinal evoked potentials by transcranial magnetic and electrical stimulation — a canine study". En Handbook of Spinal Cord Monitoring, 412–18. Dordrecht: Springer Netherlands, 1994. http://dx.doi.org/10.1007/978-94-011-1416-5_59.

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Xie, Hui, Yi Wang y Leanne Lai-Hang Chan. "Spatial Interactions of Electrically Evoked Potentials in Visual Cortex Induced by Multi-retinal Electrical Stimulation in Rats". En International Conference on Biomedical and Health Informatics, 123–28. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-4505-9_20.

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Islam, Md Nahidul, Norizam Sulaiman, Mamunur Rashid, Mahfuzah Mustafa y MohdShawal Jadin. "Investigation of Time-Domain and Frequency-Domain Based Features to Classify the EEG Auditory Evoked Potentials (AEPs) Responses". En Lecture Notes in Electrical Engineering, 497–508. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-33-4597-3_45.

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Perlman, Ido y Shiri Soudry. "Electrically Evoked Potentials". En Encyclopedia of Ophthalmology, 1–3. Berlin, Heidelberg: Springer Berlin Heidelberg, 2015. http://dx.doi.org/10.1007/978-3-642-35951-4_1038-1.

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Actas de conferencias sobre el tema "Electrical evoked potentials"

Hemalatha, G. y B. Anuradha. "Enhancement of visual evoked potentials". En 2016 International Conference on Electrical, Electronics, and Optimization Techniques (ICEEOT). IEEE, 2016. http://dx.doi.org/10.1109/iceeot.2016.7754835.

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Arar, Mahmud Esad, Burak Guclu y Mehmed Ozkan. "Design of an electrical stimulator and somatosensory evoked potentials (SEP)". En 2014 18th National Biomedical Engineering Meeting (BIYOMUT). IEEE, 2014. http://dx.doi.org/10.1109/biyomut.2014.7026359.

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Cheng, Yao, Martin Haardt, Theresa Gotz y Jens Haueisen. "Using PARAFAC2 for Multi-Way Component Analysis of Somatosensory Evoked Magnetic Fields and Somatosensory Evoked Electrical Potentials". En 2018 IEEE 10th Sensor Array and Multichannel Signal Processing Workshop (SAM). IEEE, 2018. http://dx.doi.org/10.1109/sam.2018.8448504.

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Artoni, Fiorenzo, Arianna Tanguenza, Edoardo D'Anna y Silvestro Micera. "Somatosensory Evoked Potentials following upper limb noninvasive electrical stimulation: a case study". En 2020 42nd Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) in conjunction with the 43rd Annual Conference of the Canadian Medical and Biological Engineering Society. IEEE, 2020. http://dx.doi.org/10.1109/embc44109.2020.9176722.

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Cheng, Yao, Kristina Naskovska, Martin Haardt, Theresa Gotz y Jens Haueisen. "A new coupled PARAFAC2 decomposition for joint processing of somatosensory evoked magnetic fields and somatosensory evoked electrical potentials". En 2018 52nd Asilomar Conference on Signals, Systems, and Computers. IEEE, 2018. http://dx.doi.org/10.1109/acssc.2018.8645393.

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Archambeault, Mark y Hubert de Bruin. "Development of an Electroencephalography Data Acquisition System for Clinical Research Into Transcranial Magnetic Stimulation Evoked Potentials". En 2007 Canadian Conference on Electrical and Computer Engineering. IEEE, 2007. http://dx.doi.org/10.1109/ccece.2007.56.

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Kogler, V., T. A. K. Nguyen, J. DiGiovanna y S. Micera. "Recording vestibular evoked potentials induced by electrical stimulation of the horizontal semicircular canal in guinea pig". En 5th International IEEE/EMBS Conference on Neural Engineering (NER 2011). IEEE, 2011. http://dx.doi.org/10.1109/ner.2011.5910537.

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Manthey, A., T. Rahne, SK Plontke y L. Fröhlich. "Influence of electrical pulse shapes on vestibular evoked myogenic potentials when stimulated via cochlear implant electrodes". En 100 JAHRE DGHNO-KHC: WO KOMMEN WIR HER? WO STEHEN WIR? WO GEHEN WIR HIN? Georg Thieme Verlag KG, 2021. http://dx.doi.org/10.1055/s-0041-1728392.

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Neuser, LB. "Influence of the ground path on vestibular evoked myogenic potentials with electrical stimulation via a cochlear implant". En 100 JAHRE DGHNO-KHC: WO KOMMEN WIR HER? WO STEHEN WIR? WO GEHEN WIR HIN? Georg Thieme Verlag KG, 2021. http://dx.doi.org/10.1055/s-0041-1728399.

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Sun, Mingjie, Kaijie Wu, Pengjia Cao, Xinyu Chai y Qiushi Ren. "Discrepancy of Electrical Evoked Potentials by Different Spatial-Temporal Stimulations of Optic Nerve Using Penetrating Electrode Array". En 2007 IEEE/ICME International Conference on Complex Medical Engineering. IEEE, 2007. http://dx.doi.org/10.1109/iccme.2007.4381952.

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