Search results for "ACOUSTIC"
showing 10 items of 1590 documents
An approach to the electrical tomography aimed to the investigation of particular confined structures
2003
In this paper we present a practical approach to the electrical tomography when applied to materials having particular shapes (like the columns). Simple cylindrical shapes have been tested, and the general model has been selected as a set of elements having circular sections of some angle and thickness.
Learning curve for piezosurgery in well-trained otological surgeons
2009
Abstract Objective Piezosurgery is an ultrasound instrument (24.7-29.5 kHz) capable of cutting bone without necrosis and nonmineralized tissue damage. The aim of this work has been to determine the time required for a well-trained surgeon to perform otological surgery with the piezoelectric device. Study Design Case series with planned data collection. Sixty-three patients affected by otosclerosis and 63 by chronic otitis media were enrolled. For each disease, patients were divided into three numerically equal groups, with each group assigned to a well-trained otological surgeon. Patients underwent stapedotomy (n = 63) and intact canal wall tympanoplasty (n = 63) with the piezoelectric devi…
Intraoperatives Monitoring motorischer Hirnnerven bei Operationen an Hals und Schädelbasis
1994
Intraoperative monitoring of cranial nerves is performed to minimize postoperative cranial nerve dysfunction. We performed electrophysiological monitoring of motor cranial nerves with a NIM 2 unit from Xomed Treace and a patient multiplexer developed in our clinic. This multiplexer allows simultaneous monitoring of 4 cranial nerves and is additionally equipped with a bipolar stimulation mode. This intraoperative monitoring was employed during 102 skull base operations. Of these 102 operations, 44 were acoustic neuroma removals by translabyrinthine approach and 36 by a middle fossa approach. Various operations including removal of tumours of the jugular foramen and the infratemporal fossa we…
Auditory cortical and hippocampal local-field potentials to frequency deviant tones in urethane-anesthetized rats: An unexpected role of the sound fr…
2015
Abstract The human brain can automatically detect auditory changes, as indexed by the mismatch negativity of event-related potentials. The mechanisms that underlie this response are poorly understood. We recorded primary auditory cortical and hippocampal (dentate gyrus, CA1) local-field potentials to serial tones in urethane-anesthetized rats. In an oddball condition, a rare (deviant) tone ( p = 0.11) randomly replaced a repeated (standard) tone. The deviant tone was either lower (2200, 2700, 3200, 3700 Hz) or higher (4300, 4800, 5300, 5800 Hz) in frequency than the standard tone (4000 Hz). In an equiprobability control condition, all nine tones were presented at random ( p = 0.11). Diffe…
Effekt der kontralateralen Stimulation auf evozierte otoakustische Emissionen bei akutem Hörverlust*
1994
23 patients with unilateral hearing loss and presence of TEOAE on both ears were examined with regard to the association between contralateral acoustic stimulation and evoked otoacoustic emissions. Contralateral white noise of 40 dB HL, 50 dB HL and 60 dB HL decreases the amplitude of TEOAE both at the ear with and without hearing loss. In comparison with a group of subjects with normal hearing, the decrease in the amplitude of TEOAE was less in the group of patients with hearing loss. Two paradoxical cases were found with an increase in the TEOAE amplitude in the ear with hearing loss during contralateral stimulation. It is assumed that impairment of the efferent synapses on the outer hair…
P1605Increased irregularity and spectral complexity of the intrinsic pacemaker beat-to-beat variability correlates with increased metabolic syndrome …
2019
Abstract Background Metabolic syndrome (MetS) is becoming one of the future potential leading risk factors for heart and cardiovascular disease. MetS relates to a condition associated with at least three metabolic risk factors raising risk for health diseases concomitantly such as diabetes, stroke, hypertension, obesity and dyslipidemia. This can lead to chest pain, heart attack, heart damage and overall higher prevalence of cardiovascular disease, atrial fibrillation and sudden cardiac death. One of the underlying mechanisms of the progressive remodeling in presence of MetS components could be altered automaticity, which would reflect modifications of sinus node activity. These phenomena c…
Gegenüberstellung der Wertigkeit von Angioskopie, Angiographie und Sonographie zur Erfassung pathologischer Gefäßwandprozesse
1994
AIMS The ability of angioscopy, angiography and sonography to evaluate arteriosclerotic vascular lesions were compared to determine if angioscopy is a valuable addition in the diagnostic armamentarium. METHODS An in-vitro study was selected to enable microscopic assessment of the arteries. Angiography was followed by sonography and endoscopy and finally the vessels were evaluated macro- and microscopically. RESULTS The configuration of the vascular stenosis (plaque-shape, semicircular-eccentric, circular-concentric) was more reliably defined with angioscopy as compared to angiography and sonography. Intense calcification of plaque was detected sonographically with a high sensitivity (90%) u…
Steroid and vasoactive treatment for acute deafness after attempted hearing preservation acoustic neuroma surgery.
2004
<i>Objective:</i> To investigate whether intravenous steroid and vasoactive therapy in the acute postoperative period improves hearing outcome in patients who develop acute deafness after attempted hearing preservation surgery for acoustic neuroma (AN) through a retrosigmoid or a middle cranial fossa approach. <i>Study Design and Setting:</i> Retrospective controlled study in a tertiary care center. Thirty-six patients who had developed acute deafness after hearing preservation surgery for treatment of an AN were reviewed. Preoperative AAOHNS hearing class was A in 2, B in 2 and D in 32 patients. Twenty-seven patients were treated with prednisolone, hydroxyethyl star…
Newborn hearing-screening project using transient evoked otoacoustic emissions: western sicily experience
2006
Summary Objective To study the incidence of congenital sensorineural hearing loss in all newborns introducing a screen test with a protocol no expensive, with a good “screen sensitivity” that could let an earlier identification of hearing impairment beginning early intervention by 2 months of age and increasing the probability of having language development within the normal range of development. Methods The study was conducted in Sciacca hospital from the beginning of 2003 to our days and was carried out with transient evoked otoacoustic emission using the criteria for PASS or RETEST and considering eventual prenatal and perinatal risk factors. All the newborns were divided into four group…
Quadrature domains for the Helmholtz equation with applications to non-scattering phenomena
2022
In this paper, we introduce quadrature domains for the Helmholtz equation. We show existence results for such domains and implement the so-called partial balayage procedure. We also give an application to inverse scattering problems, and show that there are non-scattering domains for the Helmholtz equation at any positive frequency that have inward cusps.