Residual hearing preservation using the suprameatal approach for cochlear implantation.

OBJECTIVE: Cochlear implantation of patients with high-frequency hearing loss and residual low-frequency hearing has become a new treatment standard within the last years. The objective of this study was to evaluate the rate of hearing preservation in cochlear implantation for electric-acoustic stimulation using the suprameatal approach. METHODS: Five patients (mean age 48.2 years) who were supplied with Med El (Combi 40+, Pulsar) cochlear implants and various different electrodes (Custom made, Flex soft, Flex EAS) were evaluated for residual hearing preservation after a mean follow-up time of 35.6 months (range 24 to 77 months). RESULTS: Three patients showed partial hearing preservation, whereas 2 patients experienced a complete loss of residual hearing. CONCLUSION: Although hearing preservation rates in this series of patients operated on using the suprameatal approach were inferior as compared with a series using the standard mastoidectomy approach, this study shows that it is in fact possible to preserve residual hearing using a non-mastoidectomy surgical technique for cochlear implantation. Nevertheless, more experience is necessary to answer the question whether this technique can be thoroughly recommended in cochlear implantation for electric-acoustic stimulation.

Outcomes in adults implanted with the FLEXsoft electrode.

CONCLUSION: Achieving deep insertions, as well as good speech perception results, the FLEXsoft electrode array allows for some preservation in subjects with measurable low frequency hearing, even after a period of time. This opens the door for future research in electrode design, hearing preservation research and drug delivery systems. OBJECTIVES: The FLEXsoft electrode is designed to be atraumatic to the structures of the cochlea during deep insertion of a cochlear implant electrode. This paper reports on the surgical and functional outcomes in implantations with the FLEXsoft electrode array. PATIENTS AND METHODS: Twenty-three adult subjects received a FLEXsoft electrode array and were assessed on speech perception tests (monosyllables, sentences in quiet and in noise), a subjective questionnaire (Nijmegen Cochlear Implant Questionnaire) and a pure-tone audiogram. Results at 1, 3, 6 and 12 months post first fitting were compared to scores from the preoperative interval. RESULTS: Surgery was uneventful in all cases, the surgical handling was satisfactory and correct position of the electrode was achieved in all cases. Hearing could be preserved (as determined by the audiogram) in half of the subjects who had measurable audiograms preoperatively at the 1 month test interval, and in a quarter of subjects after 12 months of device use, despite deep insertion of the electrode. Speech perception scores showed significant improvement over time, as did quality of life scores, and were comparable to results with the standard electrode array as used in the COMBI 40+ and PULSARCI100.

Comparison of musical activities of cochlear implant users with different speech-coding strategies.

Speech coding might have an impact on music perception of cochlear implant users. This questionnaire study compares the musical activities and perception of postlingually deafened cochlear implant users with three different coding strategies (CIS, ACE, SPEAK) using the Munich Music Questionnaire. Overall, the self-reported perception of music of CIS, SPEAK, and ACE users did not differ by very much.

High-resolution numerical model of the middle and inner ear for a detailed analysis of radio frequency absorption.

In order to enable a detailed analysis of radio frequency (RF) absorption in the human middle and inner ear organs, a numerical model of these organs was developed at a spatial resolution of 0.1 mm, based on a real human tissue sample. The dielectric properties of the liquids (perilymph and endolymph) inside the bony labyrinth were measured on samples of ten freshly deceased humans. After inserting this model into a commercially available numerical head model, FDTD-based computations for exposure scenarios with generic models of handheld devices operated close to the head in the frequency range 400-3700 MHz were carried out. For typical output power values of real handheld mobile communication devices the obtained results showed only very small amounts of absorbed RF power in the middle and inner ear organs. Highest absorption in the middle and inner ear was found for the 400 MHz irradiation. In this case, the RF power absorbed inside the labyrinth and the vestibulocochlear nerve was as low as 166 microW and 12 microW, respectively, when considering a device of 500 mW output power operated close to the ear. For typical mobile phone frequencies (900 MHz and 1850 MHz) and output power values (250 mW and 125 mW) the corresponding values of absorbed RF power were found to be more than one order of magnitude lower than the values given above. These results indicate that temperature-related biologically relevant effects on the middle and inner ear, induced by the RF emissions of typical handheld mobile communication devices, are unlikely.

Localized pericochlear hypoattenuating foci at temporal-bone thin-section CT in pediatric patients: nonpathologic differential diagnostic entity?

PURPOSE: To evaluate the prevalence of localized hypoattenuating areas in the cochlear otic capsule at temporal-bone thin-section computed tomography (CT) in pediatric patients and correlate the findings with clinical information. MATERIALS AND METHODS: Temporal-bone thin-section CT images obtained in 73 patients aged 0-9 years (20 Austrian, 53 Finnish; 36 female and 37 male patients) were evaluated for the presence of localized hypoattenuating foci in the region of the fissula ante fenestram of the otic capsule. Clinical information collected for all patients was also evaluated. The data were analyzed with a logistic regression model. RESULTS: Hypoattenuating areas in the region of the fissula ante fenestram were observed in 23 of 73 patients (32%). Hypoattenuating foci were substantially more prevalent in patients younger than 3 years than in those 3 years or older (odds ratio, 0.14; 95% CI: 0.04, 0.52; P =.001). The prevalence did not differ between sexes or according to clinical diagnosis. Only three of the 23 patients with hypoattenuating foci had clinical findings suggestive of otosclerosis, and none had osteogenesis imperfecta. After adjustment for age and sex, the finding was more prevalent among the Finnish patients (odds ratio, 5.4; 95% CI: 1.19, 24.52; P =.02) than among the Austrian patients. CONCLUSION: Hypoattenuating areas in the region of the fissula ante fenestram in the otic capsule at thin-section CT are prevalent among children younger than 3 years in the absence of clinical evidence of otosclerosis or osteogenesis imperfecta and appear in children up to 9 years old.