Evidences of vascular origin of cochleovestibular dysfunction.

OBJECTIVES: When the vascular disorder of the cochleovestibular system is mentioned, the diagnosis is based on exclusion of other diseases. Since arteries of the cochleovestibular system cannot be directly visualized, physicians must deduce from the vascular risk factors and the vascular lesion of other territories to the vascular cochleovestibular disease. MATERIALS AND METHODS: Authors analyzed the data of 19 patients with vertigo. Detailed blood tests, complete neurootological and audiological examination including ABR, carotid and vertebral artery Doppler sonography, MRI and MRA was performed. RESULTS: Cochleovestibular examination and ABR showed abnormalities in 73.7%, either carotid and vertebral artery Doppler or MRI showed abnormalities in 57.9%. MRA was abnormal in 47.4%. In most of the patients multiple risk factors of cerebrovascular disorder could be found. CONCLUSIONS: The cochleovestibular system disorders can be considered to be of vascular origin if the examinations exclude other diseases, if the patients have vascular risk factors and if other territories of brain accessible for imaging methods show vascular disorders.

New method for inserting and fixing the active electrode during cochlear implantation.

Cochlear implantation has been performed for 15 years by the authors; altogether 117 implantations were carried out during this period. Different techniques had been used: at first after having performed atticoantrotomy the active electrode was inserted through posterior tympanotomy but fixing the electrode with this method was relatively not that easy. During the last 6 years implantations were carried out using the authors' new method. At the beginning of the operation cochleostomy was prepared by means of lateral tympanotomy. Introduction of the electrode was performed through a tunnel that had been drilled previously through the posterior wall of the external auditory canal. With a piece of muscle the active electrode was properly secured in the cochleostomy and also a narrow tunnel was prepared in the posterior wall for securing the cable with a Dacron tie. The authors' method of implantation proved to be perfect for introducing the electrode and also for fixing it with long-lasting results.

Reoperations after cochlear implantation.

During the 14-year history of cochlear implantation at Semmelweis University, 95 implantations were performed. There were 15 reoperations, and 2 patients had been operated 3 times. All of the reoperated patients received round window or intracochlear MedE1 devices. Successful reinsertion of the electrode was performed without significant difficulty, though in some cases osteoneogenesis was found in the round window or in the scala tympani. None of the patients suffered any inner ear abnormalities due to the first implant, and even the patient with a third implant in the same ear had excellent results and obtained better discrimination scores with the new device. In the authors' opinion, on the basis of the accumulated experience of nearly 100 implantations and 15 reoperations, replacement of the early generation extracochlear implants is most advisable and can be accomplished without adverse effects.

Cochlear implantation influences contralateral hearing and vestibular responsiveness.

A cochlear implant program has been carried out at the ORL Clinic of Semmelweis University in Budapest since 1985. Different devices and techniques have been used in pre- and postlingual children and adults. Over the last 6 years contralateral hearing improvement has been observed in 18 patients. This phenomenon can usually be demonstrated 6 months after the operation. Since our first observation several other authors have confirmed this phenomenon. However, the underlying mechanism is still obscure; both the efferent innervation and the plasticity of the brain may be important factors. The vestibular function of cochlear implant candidates was checked routinely pre- and postoperatively and changes in vestibular responsiveness were observed. Over the last 3 years air-caloric stimulation has been performed by means of a computer-based ENG system. In most patients the vestibular function was unchanged after the implantation. but in some cases a significant improvement in vestibular responsiveness was noted. Here we briefly describe cases of re-implantation carried out at the clinic. All the patients obtained better speech discrimination scores after having been implanted with intracochlear devices. None of the patients suffered any inner ear abnormality due to the first implant.

Overview of our 13-year-long experience with cochlear implants.

Authors give account of their 13-year-old experience of cochlear implantation. Their results with different devices as well as some observations regarding fitting and rehabilitation are also discussed.

Comparative results with different cochlear implants.

The cochlear implant program in Budapest began in 1985, since when 60 operations have been performed, 14 of them on children (51 primary procedures and 9 reimplantations). Different devices and also different techniques have been used: extracochlear promontory, extracochlear round window and intracochlear implants. Various speech processors were applied; at first a digital pulsatile sound-encoding system, later on analog processors were used, while processors operating on the basis of the CIS strategy are preferred nowadays. The operations were performed on both pre- and postlingual patients. In several cases contralateral hearing improvement was observed 6 months after the operation. Considerable experience has been gained of unique cases, such as a deaf-blind prelingual child and prelingual twins. Evaluating cochlear implant performance, in addition to the usual audiological tests measuring postoperative speech understanding, warble tone sound field thresholds were also established.

[Cochlear implants]. / A cochlearis implantáció.

Cochlear implantation is a method of utmost importance recently employed in ear surgery. It makes even speech understanding possible with electrical stimulation of the inner ear in case of bilateral total deafness of cochlear origin. The authors have performed cochlear implantation for 10 years at the Ear-Nose and Throat Clinic of Semmelweis University. Since 1985 different implantation techniques have been used in case of 58 patients, both adults and children. The authors give account of of technical details, rapidly changing selection criteria and the call attention to the problems of peri- and postoperative period and rehabilitation, on they basis of their own results. Importance of team-work of the ear-surgeon, audiologist, psychologist, physicist and speech-therapist is emphasized, because success of the operation is based on proper selection, skillful operating techniques and postoperative rehabilitation, as well.

Cochlear implants in children.

The authors give an account of their experiences with cochlear implants on the basis of 10 years' work. Preoperative evaluation, operating methods and postoperative rehabilitation are presented. During a decade 56 operations were performed, 11 of them on children. Results with prelingually deaf children are demonstrated together with the phenomenon of hearing improvement observed on the contralateral side of the operation.

Surgical challenges in cochlear implantation.

Surgical experience obtained on the basis of 47 cochlear implant patients is reported. Pitfalls of perioperative and postoperative period are discussed.

Auditory brainstem potentials in uraemia.

Evoked response audiometry was carried out to assess the viability of the auditory pathway in haemodialysed patients. The latency of the waves III and V and I-V interpeak latencies were significantly longer in the renal patients compared to the control group. The I-V interpeak latency was longer in 8 of our 13 patients than the upper limit (4.38 ms) in our laboratory. The possible cause for the central auditory dysfunction may be multifactorial, including the effect of metastatic calcifications, repeated occurrence of disequilibrium syndrome, or some small, molecular, toxic, metabolic substance. The significance of the different factors may vary among different haemodialysis centres.

Diagnosis of hearing impairment in childhood.

The authors carried out BERA examinations in 46 children difficult to test. Seven cases are described in detail. In connection with these cases attention is drawn to the unforeseeable difficulties of this examination method used already widely.