Abstract Otology 2000 D14-1

Jan Helms MD, Joachim Müller MD, F. Schön MD, Wafaa E. Shehata-Dieler MD, PhD, H. Kühn-Inacker Prof.Dr.

HNO-Klinik Julius-Maximilians-Universität D-Würzburg

The cochlea implantation is accepted as the therapy of choice in bilaterally deaf patients. The improvement of life quality with successful implantation cannot be over-estimated. The best results are obviously obtained with implants using the CIS strategy with fast stimulation of more than 1200 or 1500 Hz per electrode. In order to improve the obtained results better stimulation techniques and new speech coding strategies may be developed. In addition the bilateral implantation with the optimal CIS stimulation strategy offers chances. 16 patients, adults and pre-lingual deaf children were bilaterally implanted. Two of them received their implants in a one stage surgery. In all cases, as far as postoperative speech perception could be analyzed or hearing could be estimated by behavioural controlling, the bilateral implant was advantageous to the patients.

Abstract Otology 2000 D14-2

Frank Rattay PhD, Petra Lutter PhD, Heidi Felix Ph.D.

Inst.f.Analysis, Techn. Mathem Techn. Universitaet Wien A-Wien

Our understanding of the spiking generation mechanisms in cochlear implant patients is generally derived from material based on animal data. There are, however, essential differences between the cochlear neurons in humans and the animals (cat, guinea pig and chinchilla). In contrast to the animals, the majority of cell bodies of the human cochlear afferents are unmyelinated and encapsulated by one to a few sheaths of satellite cells, i.e. they are not insulated by myelin layers. As a consequence, human somatic capacitance is significantly higher, which results in a larger somatic delay for spikes on their way from the peripheral to the central nerve processes. During electrical stimulation spikes are generated in the peripheral as well as in the central process, both in humans and animals. Our compartment model of the human cochlear neuron indicates that peripherally initiated spikes arrive with a time delay greater than 300 µs compared to spikes already generated in the central process, which is in agreement with recent neural response telemetry data. Many cochlear implant patients have a remarkable reduction of peripheral nerve processes: our computer simulations demonstrate that in contrast to animals human thresholds increase significantly, and often stimulation is possible with one stimulus polarity only.

Abstract Otology 2000 D14-3

George Psillas MD, Alex Fitzgerald O'Connor M.B. Ch. B. F.R.C.S

Audiology Department Guy's & St. Thomas' Hospital Trust GB-London

The Clarion positioner has been developed to optimize the position of the electrode within the cochlea. Six patients, five male and one female, ages 2y to 59y (mean 13,25y) were implanted using the Clarion positioner system. Intraoperatively evoked acoustic reflex threshold (IEEART) and impedances were measured before and after insertion of positioner. Assuming the total penetration of the electrode array into tympanic scala, all the patients IEEART were found to be lower with positioner than without. This was valuable for the apical, middle and basal turns, except in three subjects, where only the last one or two basal channels have shown higher IEEART. Impedance values varied randomly, indicating no clinical correlation. The IEEART results demonstrate that the electrode array was placed closer to the modiulus, near the spiral ganglion cells, with the assistance of the positioner. On the contrary, impedance values were not related to the positioner effect. Moreover, it has been shown that IEEART provides a reliable estimate of maximum confortable implant patients, is valuable and may increase overall confidence in the reliability at an estimated program map.

Abstract Otology 2000 D14-4

Cecile Schwarz Ph.D., Erika Gruner Dipl.Klin.Log.

ENT Department University Hospital CH- Zürich

With our 37 CDs and 22 textbooks we were able to create a new kind of systematic etude-like supplementary training programme (SENFT) for Cochlear Implant-patients (CI-patients). The SENFT aims at programming and connecting speech-specific areas (such as WERNICKE's- and BROCA's area) responsible for the recognition and production of phonemes in connection with language comprehension and speaking. The SENFT was developped by C.Schwarz after recognizing that in numerous CI-patients the programming of the Speech-Processor and the perfect adjustment of the electrodes alone were not sufficient to guarantee good speaking and language comprehension without lipreading. The author understood that those patients also have to have a precise phonematic stimulation and programming of the speech-specific cortical areas. Babies with normal hearing acquire their cortical elementary phonematic programming mainly during the extensive periods of crying and babbling. This enables them among other factors to develop and improve individual speech. In contrast to that the prelingual deaf babies acquire no or very little programming because of their poor babbling-phase. The SENFT can be considered as an "artificial substitute to the natural babbling programme" as it consists in innumerable variations of memorizing, repeating aloud, reading and writing all of the different phonemes and phoneme-combinations. This is presented and explained in our collection of CDs and textbooks. The accurate execution of the SENFT-technique according to our instructions is essential to bring about marked improvement of language comprehension without lipreading and of speech quality in CI-patients.

Abstract Otology 2000 D14-5

Erwin Löhle Prof.Dr., Sabine Frischmuth MD, Marianne Holm MD

Phoniatrie & Pädaudiologie HNO-Klin.d.Albert-Ludwigs-Universi D-Freiburg i.Br.

We studied the prosodic structure of utterances produced by children who received a cochlear implant between the ages of 2 and 11 years. We were especially interested in the influence of age on implantation and the ability to structure utterances in rhythmically and melodically. Our results indicate that from a certain age, the acquisition of prosodic features is no longer possible. Three different groups of children with congenitally profound hearing loss were compared: children implanted from 2 to 4 years (group 1), children implanted from 5 to 9 years (group 2) and children implanted after the age of 9 (group 3). Spectrographic analysis of spontaneous utterances showed that only children belonging to group 1 were able to develop a natural and vivid prosody, whereas children in group 2 and 3 were unable to develop prosody, so that their voices remainded monotonous.

Abstract Otology 2000 D14-6

Nikola Sprem MD, PhD, Srecko Branica MD, PhD, Krsto Dawidowsky MD

ORL Zagreb Clinical Hospital & Univers. CRO-Zagreb

A total of 21 patients were operated on one ear with a combined technique: intratympanic installation of a ventilation tube and gentamycin intratympanic installation. The reason for this approach was that in the case of failure we could repeat gentamycin treatment through ventilation tube. We treated in this manner a total of 21 patients. All patients were female and the age was between 21 to 62 years, glycerol negative.

Abstract Otology 2000 D14-7

Timo P. Hirvonen MD, PhD, M. Peltomaa MD, Jukka Ylikoski MD

Department of Otorhinolaryngology Helsinki University CentralHospital SF-Helsinki

Purpose: Intratympanic and simultaneous systemic dexamethasone treatment of Ménière's disease (MD) was evaluated in a prospective study. Methods: Seventeen patients (6 men and 11 women) with verified MD (5 right-sided, 11 left-sided and one bilateral) were treated with 0.2-0.4 mL intratympanic dexamethasone hyaluronate (16 mg/mL) injections three times during a week and a initial intramuscular dexamethasone injection of 15 mg. Their mean age was 48 (range 29-77) years and mean duration of the MD was 5.3 (range 0.8-23) years. Pure tone and speech audiometry and symptom scale of the patients were followed up to 1 year after treatment. Results: Symptoms of MD patients did not improve significantly; although a tendency to better control of vertigo attacks was found. The mean hearing level showed no significant improvement. Tinnitus and aural fullness levels remained unchanged. Conclusion: Intratympanic dexamethasone has been introduced as an alternative to treat intractable MD patients. In our preliminary study, patients of mainly late stage of MD did not benefit significantly from simultaneous intratympanic and systemic dexamethasone treatment. Thus the clinical use of dexamethasone in MD needs further evidence.

Abstract Otology 2000 D14-8

Lidija Dubrovska MD, Elena Bogeska MD, Marina Cakar MD, Gordana Mladenovska MD

ENT Department University Hospital MAZ-Skopje

Antihistamines for long time have been used for treatment of vertigo due to diseases of the vestibular system. These antihistamines have excellent efficacy but because of their side effects have had limited chronic use. Loratidine, non-sedating antihistamine has been shown to effectively reduce dizziness in our study of 10 patients with Meniere's desease and 10 patients with vestibulopathies.

Abstract Otology 2000 D14-9

Chul-Ho Jang MD, Seung T. Park MD

Dept. of ENT Wonkwang Medical School ROK-ChunBuk

In order to examine the toxic effect of oxygen radicals, the cytotoxic effects were done on cultured mouse Schwann cells facial nerve which were treated with various concentrations of xanthine oxidase(XO) and hypoxanthine(HX) for 4 hours, and also the neuroprotective effect of antioxidants on oxidant-induced neurotoxicity were also examined. The results were as follows: Cell viability of cultured mouse Schwann cells treated with XO/HX was markedly decreased in a dose-dependent manner. MTT50 value was at a concentration of 20mU/ml XO and 0.1mM HX. Cultured mouse Schwann cells exposed to 50µM STZ for 24 hours showed degenerative changes such as the decrease of cell number and process. Pretreatment of 80uM tetrakis(2-ridylmethyl)ethylenediamine(TPEN) for 2 hours increased remarkably the cell viability of cultured Schwann cells exposed to 20mU/ml XO/0.1mM HX. From these results, it is suggested that oxygen radicals induce toxic effect on cultured mouse Schwann cells, and selective antioxidant such as TPEN is very effective in blocking the oxidant-induced neurotoxicity.