Wolfgang Gstoettner

Follow up of cochlear implanted handicapped children

OBJECTIVEnTo document progress and benefit of multi-handicapped children using cochlear implants.nnnDESIGNnThe evaluation of auditory responses to speech (EARS) test battery was performed on the children in this study at regular intervals following implantation. All children went through individually tailored intensive audiological rehabilitation programs following cochlear implantation.nnnRESULTSnIndividual results from ten multi-handicapped children receiving cochlear implants are presented in this paper. The majority of children in this study are successful implant users. Whenever possible, test scores are included as well as subjective case reports.nnnCONCLUSIONnProviding multi-handicapped children with cochlear implants can result in substantial benefit for both the child and parents. Multi-handicapped children are not contraindicated for cochlear implantation, although not all are considered to be good candidates.

Cochlear Implant Deep Electrode Insertion: Extent of Insertional Trauma

We have recently undertaken deep insertions of the Combi-40 cochlear implant electrode (Med-E1 Corp., Innsbruck, Austria) into apical regions of the scala tympani using a cochleostomy approach. In order to examine the extent of the insertional trauma, 12 fresh human temporal bones were implanted with original Combi-40 electrodes. The specimens were histologically processed with the implants in place by employing a sawing and grinding technique. In most cases, only very discrete distortions of the epithelium of the spiral ligament occurred within the middle cochlear turns. Furthermore, a slight displacement of the basilar membrane caused by the electrode was occasionally seen. However, in 2 cases more severe damage such as basilar membrane rupture and electrode displacement was found. Attempts to insert the electrode beyond the point of first resistance resulted in electrode kinking within the basal cochlear turn with subsequent fracture of the osseous spiral lamina. According to our results, deep electrode insertions do not aggravate the insertional trauma provided no force is applied when resistance is felt.

Projection of primary vestibular afferent fibres to the cochlear nucleus in the guinea pig

After tracing the superior branch of the vestibular nerve and the macula sacculi by means of the neuronal tracers horseradish peroxidase (HRP) and wheat germ conjugated horseradish peroxidase (WGA-HRP), a conspicuous fibre bundle running into the cochlear nucleus could be observed. The HRP-labeled axons travel caudally through the descending vestibular nucleus, enter the cochlear nucleus at a level caudal to subgroup y and terminate at cells situated between the dorsal and posteroventral cochlear nucleus. Considering recent electrophysiological studies, it is reasonable to imply that these fibres are involved with the transduction of acoustic stimuli.

Speech perception with a cochlear implant used in conjunction with a hearing aid in the opposite ear.

The aim of this study was to determine the improvement in speech recognition provided by a cochlear implant (CI) in conjunction with a hearing aid (HA) in the opposite ear. The study was a retrospective cohort study in the context of a university teaching hospital CI programme. Seven CI patients who still use their HA in the opposite ear were tested. The scores with the CI alone and the CI in conjunction with an HA were evaluated by using three speech perception tests in quiet (Freiburger Numbers, Freiburger Monosyllables, and Innsbrucker Sentence Test). In the majority of tests and subjects, the CI alone performed better than the HA alone, and the bimodal (CI+HA) condition was superior to the CI alone. On the sentence test, the patients as a group improved from 47-96% (mean: 79%; CI alone) to 50-100% (mean: 88.1%; CI+HA, pv<0.05). With the more difficult monosyllable test, the scores improved from 15-52% (mean: 37.2%; CI alone) to 15-82% (mean: 48.7%; CI+ HA, p<0.05). On the numbers test, scores increased from 65-98% (mean: 83%; CI alone) to 75-98% (mean: 88.7%; CI+ HA, p<0.05). All patients in this study were implanted in the poorer ear. The results of the present study suggest the advantage of CI usage in conjunction with an HA in the opposite ear. Sumario El propósito de este estudio fue determinar la mejoría en el reconocimiento del lenguaje, aportado por un implante coclear (CI) y por el uso simultáneo de un auxiliar auditivo (HA) en el oído contralateral. El estudio fue una investigación retrospectiva de cohorte en el contexto de un programa de implantes cocleares en un hospital universitario. Se evaluó a siete pacientes con CI que aún utilizan su auxiliar auditivo en el oído opuesto. Se evaluaron las puntuaciones obtenidas con el IC sólo y utilizado simultáneamente con el HA, utilizando tres pruebas de percepción del lenguaje (los Números de Freiburguer, los Monosilábicos de Freiburguer y la Prueba de Frases de Innsbrucker). En la mayoría de las pruebas y los sujetos, el rendimiento del CI solo fue mejor que con el uso del HA aislado, y la condición bimodal (CI + HA) fue superior al uso del CI solo. En la prueba de frases, los pacientes como grupo mejoraron de 47-96% (media: 79%; CI solo) a 50-100% (media: 88.1%; CI + HA, p < 0.05). Con la prueba más difícil de monosilábicos, los puntajes mejoraron de 15-52% (media: 37.2%; CI solo) a 15-82% (media; 48.7%; CI + HA; p < 0.05). En la prueba de números, los puntajes aumentaron de 65-98% (media: 83%; CI solo) a 75-98% (media: 88.7%; CI + HA; p < 0.05). Todos los pacientes de este estudio fueron implantados en el peor oído. Los resultados del presente estudio sugieren la ventaja en el uso del CI en conjunto con un HA en el oído opuesto.

Towards a consensus on a hearing preservation classification system

Abstract Conclusion: The comprehensive Hearing Preservation classification system presented in this paper is suitable for use for all cochlear implant users with measurable pre-operative residual hearing. If adopted as a universal reporting standard, as it was designed to be, it should prove highly beneficial by enabling future studies to quickly and easily compare the results of previous studies and meta-analyze their data. Objectives: To develop a comprehensive Hearing Preservation classification system suitable for use for all cochlear implant users with measurable pre-operative residual hearing. Methods: The HEARRING group discussed and reviewed a number of different propositions of a HP classification systems and reviewed critical appraisals to develop a qualitative system in accordance with the prerequisites. Results: The Hearing Preservation Classification System proposed herein fulfills the following necessary criteria: 1) classification is independent from users initial hearing, 2) it is appropriate for all cochlear implant users with measurable pre-operative residual hearing, 3) it covers the whole range of pure tone average from 0 to 120 dB; 4) it is easy to use and easy to understand.

Cochlear Implant Deep‐Insertion Surgery

Intracochlear electrode placement in cochlear implant surgery is performed to maximize the chance of stimulating auditory nerve fibers as well as spiral ganglion cells. Using a round window or cochleostomy approach, insertion lengths of the nucleus electrode were found to be 17 to 19 mm.13 A total electrode insertion length of 18 to 21 mm has been described a h r performing a mastoidotomy-tympanotomy approach.4 However, insertion depths of approximately 30 mm are necessary to insert electrodes not only into basal but also into middle and apical cochlear turns. Electrode placement in these cochlear regions would improve the probability of stimulating surviving nerve fibers and provide a better correlation to cochlear tonotopy.5 For this reason, some authors recommend multiple-electrode implantations by drilling additional openings into the second turn of the cochlea.4.6

Saccular afferent fibers to the cochlear nucleus in the guinea pig

SummaryAfter tracing the vestibular nerve of the guinea pig with horseradish peroxidase (HRP), a conspicuous fiber bundle was found that passed to the ipsilateral cochlear nucleus. HRP-labeled fibers were seen to leave the descending vestibular nucleus at a level caudal to subgroup “y” in a lateral direction. Travelling close to the restiform body, the axons terminated at cells lying between the dorsal and posteroventral cochlear nucleus. These cells could be distinguished cytoarchitecturally from surrounding cells of the cochlear nuclei. Several electrophysiological investigations have assumed that there is a direct connection between the vestibular and the cochlear system. Compared to these, the fibers under consideration might be the morphological basis for such a “vestibulo-cochlear anastomosis.”

Long-term results of different treatment modalities in 37 patients with glomus jugulare tumors.

Abstract The results of different forms of treatment of 37 patients with previously untreated glomus jugulare tumors were compared retrospectively. According to the Fisch classification system, 6 patients presented with class B tumors, 19 class C and 12 patients with class D. Twenty-eight patients underwent surgery and 9 patients had primary radiation therapy (to 50 Gy). In 20 of the surgical cases (71%), radical tumor removal could be achieved and required no further treatment over a follow-up period of 8.6 years (range 2–15 years). Incomplete tumor resection with postoperative radiation therapy resulted in progressive tumor growth in three cases. One patient in this group experienced subarachnoid bleeding that had to be managed by salvage surgery. After primary radiation therapy, glomus jugulare tumors were still evident on magnetic resonance imaging scans, but showed no signs of disease progression. As a result of our experience, we found that a one-stage radical tumor resection performed in collaboration by otologic surgeons and neurosurgeons was the best treatment for patients with large glomus jugulare tumors.

Central Projections from Singular Parts of the Vestibular Labyrinth in the Guinea Pig

Primary afferent projections from singular parts of the vestibular labyrinth were studied in the guinea pig. The posterior ampullary nerve, the common trunk of the anterior and lateral ampullary nerves, as well as fibers innervating the macula sacculi or the macula utriculi were traced with crystals of horseradish peroxidase (HRP) lyophilisate. Posterior, as well as anterior and lateral ampullary fibers were found to project extensively to the superior vestibular nucleus, but also reached the other main vestibular nuclei. Saccular fibers projected mainly to the lateral parts of the lateral vestibular nucleus and to the adjoining descending and superior vestibular nuclei as well as to group y. Modest projections could be followed to the medial vestibular nucleus. Furthermore, a distinct saccular projection to the cochlear nuclei was evident. Utricular projections reached the four main vestibular nuclei with a denser accumulation of fibers within ventral parts of the lateral, descending and superior vestibular nuclei.

Cochlear implantation as a successful rehabilitation for radiation-induced deafness

Abstract Radiotherapy of the head and neck can be associated with conductive and/or sensori-neural hearing loss. We report the case of a 67-year-old man who developed complete bilateral deafness caused by labyrinthitis and radiation-induced neuritis of the acoustic nerve after postoperative radiotherapy of a nasopharyngeal carcinoma. Two years postoperatively extensive clinical workup including computed tomography and magnetic resonance imaging showed no recurrence or secondary brain tumors. To facilitate sound perception a Combi 40 cochlear implant was implanted. Because of fibrosis the insertion depth of the stimulating electrode into the scala tympani was limited and therefore a “short electrode version” was used. Six months after implantation the patient had achieved an excellent enviromental sound recognition and moderate speech intelligibility. Present experiences has shown that although radiotherapy can cause damage to the labyrinth and acoustic nerves and central hearing pathways, there may still be surviving auditory nerve fibers that can be stimulated successfully by a cochlear implant.