Abstract Otology 2000 A13-1

Geoffrey R. Ball Dr., Bob H. Katz

Symphonix Devices Inc. USA-San Jose, CA

Implantable hearing devices used for treatment of sensorineural hearing loss have now been successfully developed. This new class of implantable medical devices, called soundbridges, utilizes mechanical energy to directly drive the human ear. The potential benefits of such systems over acoustic devices include improved sound quality, the elimination of occlusion and feedback as well as improved comfort and cosmetic appearance. The focus of this paper is to describe the transducer used in our system to convert electrical energy into vibrational energy. The development of our novel device involved the implementation of a new electromagnetic design that resulted in what is now called the Floating Mass Transducer® (FMT). The design of the FMT was based on studies of the frequency response characteristics of the human ear. By characterizing the biomechanical displacements of live human ears we were able to develop a model that can be used to evaluate system performance of implantable devices in the laboratory. The frequency response characteristics of the FMT have been designed to mimic the native middle ear response to constant sound pressure. The output characteristics for the system were derived from detailed analysis of human temporal bones prior to the initiation of clinical studies. This work made it possible for the initiation of clinical trials. To date, more than two hundred patient's hundred patient's have been implanted.

Abstract Otology 2000 A13-2

Geoffrey R. Ball Dr.

Symphonix Devices Inc. USA-San Jose, CA

This paper describes measurements of the vibratory motion of the incus made with a scanning laser Doppler vibrometer. Previously we reported on the vibration of the middle ear ossicular chain driven by a middle ear implant. This previous work was completed with ears that had the tympanic membrane dissected for improved view of the entire ossicular chain. Now we report on the results obtained in the intact middle ear when driven with sound and with a middle ear implant. Detailed three-dimensional images will be presented showing the incus vibrating in response to sound and with a Floating Mass Transducer® (FMT). When the incus is driven with the FMT, the vibratory pattern closely mimics the results obtained with sound. The results obtained from this study will be presented in animated form. The implications of this work for hearing loss treatment and implantable middle ear transducer design will also be discussed.

Abstract Otology 2000 A13-3

Rüdiger Junker MD, Thomas Wilhelm MD, Arne Ernst MD

Dept. Otolaryngology Unfallkrankenhaus Berlin D-Berlin

We report on the experiences with selecting and counselling patients for implantable middle ear devices (Symphonix, Soundbridge). Two different patient populations were screened. In the first group, 45'000 patients with SNHL of different origin and in the second one, 350 patients with only noise-induced hearingloss (NIHL) were investigated. The screening process consisted of three different steps. At first, the exsisting patients´ pure-tone audiogramms (PTAs) were checked. In the second step, the patients were interviewed (motivation, concomitant diseases, acute diseases, "ear problems", i.e. ekzema, otorrhoe etc.). Finally, the patients were audiometrically tested and the recent test results used for the evaluation. In essence, a total of 346 patients from group 1 (0.8%) were good candidates for an implantable middle ear device (255 Vibrant P, 91 Vibrant HF). In group 2, the motivation of the patients was quite low because their everyday life was less impaired by their NIHL handycap. However, 5 patients were good candidates and also interested in the operative rehabilitation. Implantable hearing devices seem to become a challenging alternative to conventional hearing aids in the near future with careful evaluation of the patients.

Abstract Otology 2000 A13-4

Terry B. Nunn , Karen Archer , Alex Fitzgerald O'Connor M.B. Ch. B. F.R.C.S, Esther Griffiths , Catherene J. McKinney BSc.

Audiology Department St. Thomas Hospital GB-London

This study attempts to quantify the benefits provided by the Symphonix Vibrant Soundbridge implantable middle ear prosthesis over standard linear analogue amplification in nine patients implanted at St. Thomas' Hospital, UK. Prior to fitting with the Vibrant Soundbridge three patients wore binaural hearing aids, and six unilateral hearing aids. Subsequent to surgery, four patients received the Vibrant P audio processor, and five patients received the Vibrant HF audio processor. In order to quantify whether the Symphonix device provided any benefit over their linear analogue aids, the following measurements were made with the patient's hearing aids, and repeated with the Vibrant Soundbridge device: (1) functional gain and frequency response using free-field aided thresholds (2) speech intelligibility in quiet and noise using an automated sentence test (FAAF) and BKB sentences (3) qualitative benefit using the Abbreviated Profile of Hearing Aid Benefit (APHAB) and an abridged version of the Hearing Device Satisfaction Scale (HDSS) The results of these outcome measures using the two devices will be presented. Implications for the management of patients will be discussed.

Abstract Otology 2000 A13-5

Thomas Lenarz MD

HNO-Klinik Medizinische Hochschule Hannover D-Hannover

Conventional hearing aids have substantial disadvantages in terms of sound quality, feedback, distortion, occlusion effect and cosmetic appeal. Most of these problems are related to the small transducers located in the external auditory canal. Electromagnetic transducers which are directly coupled onto the ossicular chain have been developed to overcome these problems. Two systems are available for human use: the Symphonix soundbridge system and the Otologics Middle Ear Transducer (MET). 32 patients have been implanted with the Symphonix device since 1997, 5 patients have been implanted with the MET. The main selection criteria include moderate to severe sensorineural bilateral hearing loss, recurrent external otitis, monosyllable word understanding under best aided conditions below 50 % or insufficient functional gain with conventional hearing aids. The majority of the patients report improved sound quality and superior comfort with the devices. The lack of feedback and occlusion and reduced distortions are key advantages. The functional gain varies substantially between patients. The same holds true for improvement in speech understanding. Compared to conventional hearing aids the best results are seen in patients who have not used hearing aids for a longer period prior to surgery. 50 % of the patients continue to wear their conventional hearing aid on the contralateral side. Side-effects are uncommon. One patient had substantial sensorineural hearing loss postoperatively in the high frequency region. Conclusion: Semi-implantable hearing aids are a new treatment modality for patients suffering from moderate to severe sensorineural hearing loss. They provide superior sound quality and better speech understanding in noise. They allow easy upgrade due to technological development by exchange of the external audio processor. Long-term results are so far encouraging with no deterioration of performance over time and no medical complications.

Abstract Otology 2000 A13-6

Stefan Dazert MD, Wafaa E. Shehata-Dieler MD, PhD, Ralf J. Dieler MD, Jan Helms MD

Dept. of ORL-HNS University of Würzburg D-Würzburg

About 14 million people in Germany suffer from a sensorineural hearing impairment. The adequate therapy for these patients consists of a supply with electronic hearing devices. Conventional hearing aids are often not well tolerated because of insufficient amplification in the high frequency range, problems with the ear mold (feed back, occlusion, external otitis) or distortion of sound signals with an "unnatural" hearing impression. The partially implantable middle ear device Vibrant Soundbridge (VS) (Symphonix Devices AG, Basel, CH) provides a sound wave conversion into mechanical vibrations at the middle ear ossicles using the so called "Floating Mass Transducer" (FMT). The audiological advantages are due to a direct moving force of the perilymph. The VS system is indicated in patients with a middle to severe symmetrical sensory hearing loss and physiological middle ear conditions. Prior to surgery, patients undergo a fitting procedure with a conventional hearing aid and need to be unsatisfied with the device. The expected advantage of the VS system does not justify a surgical implantation procedure in patients who are happy with conventional hearing aids. At the Department of ORL-HNS, University of Würzburg, five patients have been provided with the VS system. These patients report a "natural" quality of speech and sounds, an improved speech understanding in noise, a better hearing perception at high frequency sounds and the absence of the feed back phenomenon. Audiological investigations and questionnair results support the subjective hearing impression of the patients.

Abstract Otology 2000 A13-7

Marcus M. Maassen MD, PhD (1), Peter K. Plinkert MD, PhD (1), Hans Leysieffer PhD (2), Hans Peter Zenner MD (1)

(1) Department of Otolaryngology University Hospital of Tübingen D-Tübingen
(2) Implex AG Hearing Technology D-München

The electronic hearing system Implex TICA is a totally integrated hearing implant for the treatment of sensorineural hearing loss. It consists of three components: (1) a microphone (0,4g) for subcutaneous implantation into the posterior canal wall, (2) a retroauricular, subcutaneously placed electronic module containing a digitally programmable three-channel audioprocessor and an accumulator and (3)a piezoelectric transducer. The transducer (0,4g) has a titanium coupling rod, which transfers mechanical oscillations to the incus body and from there to the inner ear. After the transducer is fixed with a special osteosynthesis plate, the integrated micromanipulator allows movement in all directions in the mastoid cavity. The presentation shows the surgical technique with a total mastoidectomy, a trepanation of the posterior canal wall and the implantation of the three TICA-components.