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At least 325 records · Page 18Linked to original sources
PubMed1997

A consideration of the effect of ear canal resonance and hearing loss upon white noise generators for tinnitus retraining therapy.

Tinnitus retraining therapy has been heralded as a major advance in the alleviation of tinnitus perception. A cornerstone of this technique is to use white noise produced by a white noise generator (WNG) over a period of several months in order to assist the patient to habituate to their tinnitus. There are three factors which influence the frequency spectrum of the perceived noise such that the perception of white noise from a WNG is unlikely. These factors are the actual spectrum of the emitted noise, the ear canal resonance of the patient and the hearing sensitivity of the patient. Advocates of tinnitus retraining therapy state that white noise is the optimal stimulation to assist habituation of tinnitus. This paper demonstrates that this optimal situation is unlikely to be achieved and that this may account for the long periods needed for patients to achieve benefit from the technique. The development of devices that allow for the above factors to be countered is suggested.

Acoustic Stimulation↗
PubMed2000

Facial nerve paralysis following repair of the external ear canal with ionomeric cement.

A 20-year-old man developed a complete facial nerve paralysis following surgical reconstruction of the posterior ear canal with ionomeric cement. The paralysis developed gradually during the second and third postoperative weeks. Six weeks following the complete removal of the cement, the facial nerve recovered completely. The literature contains reports of diffusion of aluminum ions, which can reach toxic levels in tissue fluid and adjacent bone as the cement hardens. This side effect has been reported to cause an inflammatory response in the dura and brain and has led to fatalities. To our knowledge, there has been no other report of an ionomeric cement having a direct toxic effect on peripheral nerve transmission. Because ionomeric cements are used routinely in otosurgery, especially in canal reconstructions where the proximity to the facial nerve is evident, it is important to use caution when introducing ionomeric cements into near-nerve anatomic locations.

Adult↗
PubMedDate not supplied

[The identification of wave I in ABR, ear-canal electrode and electrocochleography].

The diagnosis value of auditory brainstem response (ABR) lies in the fact that they make possible to measure the times conduction of the pathway from the cochlea to the topo part of the brainstem, enabling the diagnosis in an objective way of hearing deficits and their classifying as well. The analysis of the times of conduction are based on the measuring of the latency of waves and the interwave intervals, being fundamental the latency of waves I and V and the interval between them (I-V). But sometimes the registrations of ABR, obtained at intensities nearing hearing threshold or in many patients with significant hearing loss obtained through the traditional method from the scalp, do not permit as the identification of wave I, which causes a reduction in the value of ABR diagnosis. Our work tries to analyze the different techniques which could solve that reduction. To achieve it we have to compare the registrations of ABR obtained from the scalp to those obtained using a EAR canal electrode and to Auditory Nerve Action Potential obtained through Transtympanic Electrocochleography, analyzing the latency, the amplitudes and the intervals of the different waves and specially the growth in the amplitude of wave I, and the subsequent improvement given back to ABR all their diagnosis value.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed1999

Prediction of conductive hearing loss based on acoustic ear-canal response using a multivariate clinical decision theory.

This study evaluated the accuracy of acoustic response tests in predicting conductive hearing loss in 161 ears of subjects from the age of 2 to 10 yr, using as a "gold standard" the air-bone gap to classify ears as normal or impaired. The acoustic tests included tympanometric peak-compensated static admittance magnitude (SA) and tympanometric gradient at 226 Hz, and admittance-reflectance (YR) measurements from 0.5 to 8 kHz. The performance of individual, frequency-specific, YR test variables as predictors was assessed. By applying logistic regression (LR) and discriminant analysis (DA) techniques to the multivariate YR response, two univariate functions were calculated as the linear combinations of YR variables across frequency that best separated normal and impaired ears. The tympanometric and YR tests were also combined in a multivariate manner to test whether predictive efficacy improved when 226-Hz tympanometry was added to the predictor set. Conductive hearing loss was predicted based on air-bone gap thresholds at 0.5 and 2 kHz, and on a maximum air-bone gap at any octave frequency from 0.5 to 4 kHz. Each air-bone gap threshold ranged from 5 to 30 dB in 5-dB steps. Areas under the relative operating characteristic curve for DA and LR were larger than for reflectance at 2 kHz, SA and Gr. For constant hit rates of 80% and 90%, both DA and LR scores had lower false-alarm rates than tympanometric tests-LR achieved a false-alarm rate of 6% for a sensitivity of 90%. In general, LR outperformed DA as the multivariate technique of choice. In predicting an impairment at 0.5 kHz, the reflectance scores at 0.5 kHz were less accurate predictors than reflectance at 2 and 4 kHz. This supports the hypothesis that the 2-4-kHz range is a particularly sensitive indicator of middle-ear status, in agreement with the spectral composition of the output predictor from the multivariate analyses. When tympanometric and YR tests were combined, the resulting predictor performed slightly better or the same as the predictor calculated from the use of the YR test alone. The main conclusion is that these multivariate acoustic tests of the middle ear, which are analyzed using a clinical decision theory, are effective predictors of conductive hearing loss.

Acoustic Impedance Tests↗