942 resultados para Evoked potentials (Electrophysiology)


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Objectives: (1) To establish test performance measures for Transient Evoked Otoacoustic Emission testing of 6-year-old children in a school setting; (2) To investigate whether Transient Evoked Otoacoustic Emission testing provides a more accurate and effective alternative to a pure tone screening plus tympanometry protocol. Methods: Pure tone screening, tympanometry and transient evoked otoacoustic emission data were collected from 940 subjects (1880 ears), with a mean age of 6.2 years. Subjects were tested in non-sound-treated rooms within 22 schools. Receiver operating characteristics curves along with specificity, sensitivity, accuracy and efficiency values were determined for a variety of transient evoked otoacoustic emission/pure tone screening/tympanometry comparisons. Results: The Transient Evoked Otoacoustic Emission failure rate for the group was 20.3%. The failure rate for pure tone screening was found to be 8.9%, whilst 18.6% of subjects failed a protocol consisting of combined pure tone screening and tympanometry results. In essence, findings from the comparison of overall Transient Evoked Otoacoustic Emission pass/fail with overall pure tone screening pass/fail suggested that use of a modified Rhode Island Hearing Assessment Project criterion would result in a very high probability that a child with a pass result has normal hearing (true negative). However, the hit rate was only moderate. Selection of a signal-to-noise ratio (SNR) criterion set at greater than or equal to 1 dB appeared to provide the best test performance measures for the range of SNR values investigated. Test performance measures generally declined when tympanometry results were included, with the exception of lower false alarm rates and higher positive predictive values. The exclusion of low frequency data from the Transient Evoked Otoacoustic Emission SNR versus pure tone screening analysis resulted in improved performance measures. Conclusions: The present study poses several implications for the clinical implementation of Transient Evoked Otoacoustic Emission screening for entry level school children. Transient Evoked Otoacoustic Emission pass/fail criteria will require revision. The findings of the current investigation offer support to the possible replacement of pure tone screening with Transient Evoked Otoacoustic Emission testing for 6-year-old children. However, they do not suggest the replacement of the pure tone screening plus tympanometry battery. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.

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1 The effect of chronic morphine treatment (CMT) on sympathetic innervation of the mouse vas deferens and on alpha (2)-adrenoceptor mediated autoinhibition has been examined using intracellular recording of excitatory junction potentials (EJPs) and histochemistry. 2 In chronically saline treated (CST) preparations. morphine (1 muM) and the alpha (2)-adrenoceptor agonist (clonidine, 1 muM) decreased the mean amplitude of EJPs evoked with 0.03 Hz stimulation by 81+/-8% (n=16) and 92+/-6% (n=7) respectively. In CMT preparations, morphine (1 muM) and clonidine (1 muM) decreased mean EJP amplitude by 68+/-8% (n = 7) and 79+/-8% (n = 7) respectively. 3 When stimulating the sympathetic axons at 0.03 Hz. the mean EJP amplitude recorded from smooth muscles acutely withdrawn from CMT was four times greater than for CST smooth muscles (40.7+/-3.8 mV, n = 7 compared with 9.9+/-0.3 mV, n = 7). 4 Part of the increase in mean EJP amplitude following CMT was produced by a 31% increase in the density of sympathetic axons and varicosities innervating the smooth muscle. 5 Results from the present study indicate that the effectiveness of alpha (2)-adrenocrptor mediated autoinhibition is only slightly reduced in CMT preparations. Most of the cross tolerance which develops between morphine, clonidine and alpha (2)-adrenoceptor mediated autoinhibition occurs as a consequence of increased efficacy of neuromuscular transmission which is produced by an increase in the probability of transmitter release and an increase in the density of sympathetic innervation.

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Objectives: The present study aimed to investigate the feasibility and practicalities or testing children in special school settings using transient evoked otoacoustic emissions (TEOAE) and tympanometry. Children studying in special schools, particularly those with intellectual impairment, may be highly susceptible to hearing pathologies and can be difficult to assess using traditional test batteries. Researchers have recently suggested the possible applicability of TEOAE testing. in lieu of conventional behavioral methods, as a hearing screening device for persons with intellectual impairment. However, to date. few publications have detailed the particulars and results of such testing. Methods: A total of 489 children, with a mean age of 9.6 years, were tested in 15 special schools. Case information was obtained regarding birth history, medical history and type,degree of impairment, for later comparison with screening results. TEOAEs were collected using Quickscreen mode of the ILO292 Otodynamics Analyzer, whilst tympanometry was performed utilizing a Madsen Zodiac 901 Middle Ear Analyzer. Results: In total, 80% of students were able to be tested using TEOAEs. Average test time per ear was 2 min. However, a large proportion (40 of those able to be tested) failed TEOAE testing in at least one ear. No significant effects were found between could-not-test (CNT) cases and case history factors, A significant difference in TEOAE failure rates was found across history of neonatal special care nursery residency and history of parental concern regarding possible hearing impairment. Failure rates were higher for those who indicated positive histories. A total of 74% of subjects could be tested using tympanometry, with 25% of those able to be tested failing in at least one ear. Notably, neither type nor degree of impairment had any significant bearing on CNT or failure rates for tympanometry or TEOAE screening. Conclusions: Findings of the present investigation lend support to the review of hearing screening programs for children in special schools. with TEOAEs presenting as a potential alternative procedure. Further examination of the performance measures of protocols incorporating TEOAEs would now be advantageous. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.

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The purpose of this study was to compare transient evoked otoacoustic emission (TEOAE) screening outcomes (pass/fail) across the seasons (spring, autumn, and winter) between infants and schoolchildren. A total of 526 infants (275 boys, 251 girls) with a mean age of 2.0 months (SD = 0.38 months) and 975 schoolchildren (513 boys, 462 girls) with a mean age of 6.2 years (SD = 0.36 years) were screened using the ILO Otodynamics Quickscreen program. The same TEOAE pass/fail criterion was applied to the two groups. The results indicated a significant difference in pass rates between infants (91.2% of 1052 ears) and schoolchildren (86.0% of 1950 ears). A seasonal effect was found only for schoolchildren, with a significantly lower pass rate in winter than in spring or autumn. There was no difference in pass rates between spring and autumn. Implications for the seasonal effect on TEOAE screening outcomes for infants and schoolchildren are discussed.

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Handedness, as a potentially influencing, nonpathologic factor, has not been investigated in relation to transient evoked otoacoustic emissions (TEOAEs). The present study aimed to examine the effects of handedness on the TEOAE spectrum in entry-level schoolchildren, with attention also to possible ear asymmetry. A total of 228 subjects (114 males, 114 females, mean age = 6.3 years) were tested using the ILO292 Otodynamics Analyzer (Quickscreen mode) in quiet rooms in 22 schools. For statistical analysis, subjects were matched for factors such as handedness, gender, age, and history of recent ear infection. The results from subjects with passing TEOAE, pure-tone screening, and tympanometry revealed no significant handedness effect overall, although a significant ear asymmetry effect on the measurement parameters of AB difference, noise level, response level, whole-wave reproducibility, band reproducibility, and signal-to-noise ratios was found.

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This study compares the performance of the Quickscreen and Default protocols of the ILO-96 Otodynamics Analyzer in recording transient evoked otoacoustic emissions (TEOAEs) from adults using clinical decision analysis. Data were collected from 25 males (mean age = 29.0 years, SD = 6.8) and 35 females (mean age = 28.1 years, SD = 9.6). The results showed that the mean signal-to-noise ratios obtained from the Quickscreen were significantly greater than those from the Default protocol at 1,2, and 4 kHz. The comparison of the performance of the two protocols, based on the results using receiver operating characteristics curves, revealed a higher performance of the Quickscreen than the Default protocol at 1 and 4 kHz but not at 2 kHz. In view of the enhanced performance of the Quickscreen over the Default protocol in general, the routine use of the Default protocol for testing adults in audiology clinics should be reconsidered.

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In this work, we investigated structural, morphological, electrical, and optical properties from a set of Cu2ZnSnS4 thin films grown by sulfurization of metallic precursors deposited on soda lime glass substrates coated with or without molybdenum. X-ray diffraction and Raman spectroscopy measurements revealed the formation of single-phase Cu2ZnSnS4 thin films. A good crystallinity and grain compactness of the film was found by scanning electron microscopy. The grown films are poor in copper and rich in zinc, which is a composition close to that of the Cu2ZnSnS4 solar cells with best reported efficiency. Electrical conductivity and Hall effect measurements showed a high doping level and a strong compensation. The temperature dependence of the free hole concentration showed that the films are nondegenerate. Photoluminescence spectroscopy showed an asymmetric broadband emission. The experimental behavior with increasing excitation power or temperature cannot be explained by donor-acceptor pair transitions. A model of radiative recombination of an electron with a hole bound to an acceptor level, broadened by potential fluctuations of the valence-band edge, was proposed. An ionization energy for the acceptor level in the range 29–40 meV was estimated, and a value of 172 ±2 meV was obtained for the potential fluctuation in the valence-band edge.

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Benign focal epilepsy in childhood with centro-temporal spikes (BECTS) is one of the most common forms of idiopathic epilepsy, with onset from age 3 to 14 years. Although the prognosis for children with BECTS is excellent, some studies have revealed neuropsychological deficits in many domains, including language. Auditory event-related potentials (AERPs) reflect activation of different neuronal populations and are suggested to contribute to the evaluation of auditory discrimination (N1), attention allocation and phonological categorization (N2), and echoic memory (mismatch negativity – MMN). The scarce existing literature about this theme motivated the present study, which aims to investigate and document the existing AERP changes in a group of children with BECTS. AERPs were recorded, during the day, to pure and vocal tones and in a conventional auditory oddball paradigm in five children with BECTS (aged 8–12; mean = 10 years; male = 5) and in six gender and age-matched controls. Results revealed high amplitude of AERPs for the group of children with BECTS with a slight latency delay more pronounced in fronto-central electrodes. Children with BECTS may have abnormal central auditory processing, reflected by electrophysiological measures such as AERPs. In advance, AERPs seem a good tool to detect and reliably reveal cortical excitability in children with typical BECTS.

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Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.

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Based on a survey sent to Portuguese centers that perform diagnostic and interventional electrophysiology and/or implantable cardioverter-defibrillator (ICD) implantations, the authors analyze the number and type of procedures performed during 2012 and compare these data with previous years. In 2012, a total of 2561 diagnostic electrophysiologic studies were performed, which were followed by ablation in 2017 cases, representing a steady situation compared with the previous year. There was a 12% increase in the number of ablation procedures for atrial fibrillation, making it for the first time the most frequent indication for ablation, overtaking atrioventricular nodal reentrant tachycardia. The total number of first ICD implantations was 1048 (around 100 per million population), of which 375 were cardiac resynchronization devices (BiV ICDs). This represents a slight decrease (3.3%) in the total number of new implants, with an increase of 10% in the number of BiV ICDs compared to the previous year. However, there was a considerable increase in the number of ICD generator replacements, resulting in an overall increase of 3.5% in implantations performed in 2012. Some comments are made regarding developments in this activity and its current status, and on some factors that may influence the dynamics of this area of interventional cardiology.