Surgical capping of superior semicircular canal dehiscence.

Surgical plugging and resurfacing are well established treatments of superior semicircular canal dehiscence, while capping with hydroxyapatite cement has been little discussed in literature. The aim of this study was to prove the efficacy of the capping technique. Charts of patients diagnosed with superior semicircular canal dehiscence were reviewed retrospectively.

Intra- and intersubject comparison of cochlear implant systems using the Esprit and the Tempo+ behind-the-ear speech processor.

A patient with bilateral profound deafness was implanted with a Nucleus CI24M cochlear implant (CI) and used an Esprit behind-the-ear (BTE) speech processor. Thirteen months later, the implant had to be removed because of a cholesteatoma. As the same electrode could not be reinserted, a Medel combi40s CI was implanted in the same ear, and the patient used a Tempo+ BTE processor.

Performance of an adaptive beamforming noise reduction scheme for hearing aid applications. II. Experimental verification of the predictions.

A method to predict the amount of noise reduction which can be achieved using a two-microphone adaptive beamforming noise reduction system for hearing aids [J. Acoust. Soc.

Performance of an adaptive beamforming noise reduction scheme for hearing aid applications. I. Prediction of the signal-to-noise-ratio improvement.

Adaptive beamformers have been proposed as noise reduction schemes for conventional hearing aids and cochlear implants. A method to predict the amount of noise reduction that can be achieved by a two-microphone adaptive beamformer is presented. The prediction is based on a model of the acoustic environment in which the presence of one acoustic target-signal source and one acoustic noise source in a reverberant enclosure is assumed.

Electromagnetic interference of bone-anchored hearing aids by cellular phones.

We report a case of electromagnetic interference between a bone-anchored hearing aid (BAHA) and a cellular phone. A 54-year-old women was successfully treated for severe mixed conductive and sensorineural hearing loss with a BAHA. Five years after implantation, the patient experienced a sudden feeling of dizziness, accompanied by a loud buzzing sound and by a sensation of head pressure while examining a digital mobile phone.

A novel real-time noise reduction system for the assessment of evoked otoacoustic emissions.

A novel noise reduction method and apparatus to be used in connection with the measurement of evoked otoacoustic emissions (EOAE) are presented. The noise reduction method is based on an adaptive noise canceller and requires a noise-only reference microphone placed in the vicinity of the OAE-probe. The method was implemented in real time on a custom built digital signal processing system using an Analog Devices ADSP-2181 digital signal processor.

Performance of compressed analogue (CA) and continuous interleaved sampling (CIS) coding strategies for cochlear implants in quiet and noise.

Speech understanding with compressed analogue (CA) and continuous interleaved sampling (CIS) coding strategies for cochlear implants was compared in quiet and in noise at signal-to-noise ratios (SNRs) of 15, 10 and 5 dB. The speech recognition of three experienced users of the Ineraid cochlear implant (CA coding strategy) was assessed using a set of sentence, vowel and consonant tests. Three weeks after the fitting of a CIS processor, the tests were repeated with the new device.

Subjective visual vertical in peripheral unilateral vestibular diseases.

In humans, the perception of vertical is provided by input from various sensorineural organs and pathways: vision, eye-movements, and proprioceptive and vestibular cues, particularly from the otolithic organs and graviceptive pathways. Well known in several types of brainstem lesions, subjective visual vertical (SVV) abnormalities may also be observed after peripheral vestibular lesions, such as surgical deafferentation, with a deviation directed toward the operated ear. Subjective visual vertical abnormalities are presumably related to a lesion of the otolithic organs and/or to changes in the afferent graviceptive pathways.

Advantages and dangers of erbium laser application in stapedotomy.

Among different types of lasers, the erbium laser exhibits particularly favourable characteristics for ear surgery. Experiments with application of erbium laser pulses to the isolated stapes connected to an inner ear model confirmed that there was virtually no thermal effect to the inner ear liquid and that the border damage zone on the stapes footplate perforation did not exceed 5-10 microm. Erbium laser pulses, however, produce pressure waves due to the explosive ablation of tissue.

Effect of high-frequency electrical stimulation of the auditory nerve in an animal model of cochlear implants.

Hypothesis: Electrical stimulation of the cochlea at high rates induces significant adaptation of the auditory nerve.

Background: A new development of cochlear implants is the use of speech processors delivering electrical pulses on the implanted electrodes at high rates, such as 1,000 pulses per second (pps) and above. Such a stimulation mode allows subjects with cochlear implants to reach excellent understanding of speech.

Single unit activity in the inferior colliculus of the rat elicited by electrical stimulation of the cochlea.

The activity of single neurons (n = 182) of the central nucleus of the inferior colliculus (CIC) of the rat was recorded in response to unilateral electrical stimulation of the left cochlea and/or acoustical stimulation of the right ear. The probability of response to both modes of stimulation was comparable (90 per cent for contralateral and 60 per cent for ipsilateral presentation). Response patterns consisted predominantly of onset excitations.

Diplopia from skew deviation in unilateral peripheral vestibular lesions.

Vertical diplopia from skew deviation is well described in brainstem lesions. The phenomenon can also result from peripheral vestibular lesions. During the past years, we have observed these ocular changes in the acute stage following unilateral vestibular neurectomy and labyrinthectomy (n = 13), as well as in series of patients suffering from idiopathic sudden unilateral peripheral vestibular or cochleo-vestibular deficit (n = 5).

Ocular tilt reaction associated with a sudden idiopathic unilateral peripheral cochleovestibular loss.

We recently observed a female patient who was suffering from acute right peripheral cochleovestibular loss associated with a marked vertical diplopia. Otoneurological examination showed profound deafness, and absence of nystagmic response to caloric and pendular rotatory test in the right ear. Neuroophthalmological examination showed skew deviation with right hypotropia, excyclotorsion, and tilt of the static visual vertical directed to the right side.

Activity elicited in the auditory pathway of the rat by electrical stimulation of the cochlea.

The activity elicited by electrical stimulation of the cochlea in the auditory pathway was assessed in an animal model of cochlear implants on the basis of the induction of the immediate early gene c-fos and single neuron recordings. Electrical stimulation of the cochlea induced Fos-like immunoreactivity in the cochlear nucleus, mainly in its dorsal nucleus, in the superior olivary complex, in the lateral lemniscus, but not in the central nucleus of the inferior colliculus, the main relay nucleus in the auditory midbrain. However, single unit recordings from the inferior colliculus, ipsilateral and contralateral to the electrically stimulated cochlea, showed clear responses of single neurons, reminiscent of those elicited by acoustic stimulation.

Bilateral idiopathic loss of peripheral vestibular function with normal hearing.

From 1982 to 1993, 52 electronystagmograms (FNG) revealed an absent nystagmic reaction on both caloric (44 30 and 10 degrees C water irrigation) and rotatory pendular testing (0.05 Hz/peak velocity 60 degrees/s), which represents 0.6% of all FNG performed during this period.

Distribution of Fos-like immunoreactivity in the auditory pathway of the Sprague-Dawley rat elicited by cochlear electrical stimulation.

Fos-like immunoreactivity (FLI) was mapped in the auditory pathway of Sprague-Dawley rats in response to unilateral electrical stimulation of the cochlea implanted with two stimulating electrodes. Densely packed FLI neurons were widely distributed in the dorsal cochlear nucleus (more ipsilaterally than contralaterally), while FLI neurons were rare in the posteroventral cochlear nucleus and virtually absent in the anteroventral cochlear nucleus. Sparse FLI was detected in the superior olivary complex, the pontine nuclei and the ipsilateral dorsal nucleus of the lateral lemniscus, whereas the contralateral dorsal nucleus of the lateral lemniscus was moderately labeled.