Search results for "cochlea"
showing 10 items of 135 documents
Auditory Late Cortical Response and Speech Recognition in Digisonic Cochlear Implant Users
2002
Objective The purpose of the study was to test for differences in late electrically evoked auditory potentials between subjects exhibiting “good” versus “poor” speech recognition performances with their cochlear implants. Methods Late auditory evoked responses were measured in 30 subjects equipped with the Digisonic (MXM, Antibes, France) cochlear implant, 15 of whom had “good” speech recognition scores (i.e., more than 89% correct phoneme identification without lip reading). The 15 other subjects had poorer speech recognition scores (i.e., less than 85%). Results Differences in N1P2 amplitude, as well as P1, N1, and P2 latencies, and N1-P1 and N1-P2 latency intervals were tested. Wave P2 l…
Radiosurgery as Treatment for Acoustic Neuroma. Ten Years’ Experience
2013
The acoustic neuroma is a benign tumour that usually affects the vestibular portion of the vestibulocochlear nerve. It represents 8% of all intracranial tumours and 80% of those arising at the cerebellopontine angle. There are 3 treatment options: microsurgery (the technique of choice), radiosurgery and observation. The objective of the study was to evaluate the results and side effects obtained using radiosurgery as treatment for acoustic neuroma.We performed a review of all patients treated with radiosurgery (Gamma Knife and linear accelerator) at doses of 1200-1300 cGy for unilateral acoustic neuroma in our hospital from January 1999 until January 2010. In all patients we evaluated the o…
Treatment of sudden sensorineural hearing loss with transtympanic injection of steroids as single therapy: a randomized clinical study.
2011
The aim of this study was to verify the efficacy and the safety of transtympanic dexamethasone to treat sudden sensorineural hearing loss as first and single drug method. Considering ethical implication of performing a mininvasive procedure on middle ear, we matched such proposed treatment with systemic prednisone administration that represents the widest adopted protocol. Randomized prospective study was conducted. The inclusion criterion was a sudden sensorineural hearing loss of at least 30 dB across three contiguous frequencies over a period of 24 h. Group A received transtympanic steroid injections; Group B received oral administration of steroids. 25 patients were treated with transty…
Effect of changing pulse rate on profile parameters of perceptual thresholds and loudness comfort levels and relation to ECAP thresholds in recipient…
2010
Abstract: The Nucleus CI24RE Freedom device offers higher stimulation rates and lower noise levels in action potential measurements (ECAPs) than previous devices. A study including ten European implant teams showed that the effect of changes in rate from 250 to 3500 pulses per second on tilt and curvature of the T and C profiles is insignificant. When changing rate one may change the levels at all electrodes by the same amount. Using an automated procedure ECAPs could be measured quickly and reliably at a noise level of only 1 μV. However, this did not result in improved correlations between the tilt and curvature parameters of the ECAP profiles and those of the T and C profiles. Average C …
Speech perception performance as a function of stimulus pulse rate and processing strategy preference for the Cochlear™ Nucleus®CI24RE device: Relati…
2010
Current cochlear implants can operate at high pulse rates. The effect of increasing pulse rate on speech performance is not yet clear. Habituation to low rates may affect the outcome. This paper presents the results of three subsequent studies using different experimental paradigms, applying the Nucleus CI24RE device, and conducted by ten European implant teams. Pulse rate per channel varied from 500 to 3500 pulses per second with ACE and from 1200 to 3500 pps with CIS strategy. The results showed that the first rate presented had little effect on the finally preferred rate. Lower rates were preferred. The effect of pulse rate on word scores of post-linguistic implantees was small; high rat…
Analysis of Fifty-Six Cochlear Implant Device Failures
2008
<i>Objective:</i> Our aim was to present a failure analysis after cochlear implant revision surgery in a large series of children and adults and to assess the outcome and audiologic performance. <i>Methods:</i> Fifty-six cochlear implant failures that occurred in 422 devices implanted between 1990 and 2007 at the Department of Otolaryngology, Head and Neck Surgery at the University of Mainz, Germany, were retrospectively analyzed. The causes of failure were reviewed evaluating the individual history, telemetric and intraoperative findings and manufacturer’s investigation reports. <i>Results:</i> We performed 56 surgical revisions in a series of 422 consec…
Reliability of cochlear implants.
2005
Background The long-term reliability of cochlear implants over time is an important issue for patients and cochlear implant teams. The calculation of cumulative survival rates including all hard failures of cochlear implants is suitable to report objectively about cochlear implant reliability. Methods This is a report of 192 cochlear implants from different manufacturers in adults (n = 58) and children (n = 134). Results The overall cumulative implant survival rate was 91.7% for a period of 11 years. The main reasons for hard failures were design errors of the products and direct or indirect trauma to the cochlea implant site (especially in children) with consecutive breaks of the implant b…
Technical Note: Minimal Access Surgery for Cochlear Implantation with MED-EL Devices
2005
<i>Background:</i> Minimally invasive techniques have been described for cochlear implant surgery, but so far this had not been the case for Med-EL devices. <i>Objective:</i> To describe a newly developed minimal access approach for the implantation of Med-EL devices and report our results after up to 1 year of follow-up in 52 patients. <i>Discussion:</i> The use of a minimally invasive approach without raising a flap or extensive drilling of a bony well was feasible in all 52 patients of this series. It shortened the surgical time to an average of 45 min and there were no specific postoperative complications. The average follow-up of 8.4 months was uneve…
Effects of contralateral white noise stimulation on transitory evoked otoacoustic emissions in patients with acoustic neuroma.
1995
Abstract Transitory evoked otoacoustic emissions are normal phenomena observed in most persons with hearing levels greater than 35 dB. Further, masking of the contralateral ear produces amplitude reductions in the transitory evoked otoacoustic emissions. We have undertaken a study of transitory evoked otoacoustic emissions in 20 patients with acoustic neuroma. All patients were assessed for transitory evoked otoacoustic emissions bilaterally, with and without contralateral masking with white band noise at 40, 50, and 60 dB. We found that transitory evoked otoacoustic emissions were present in 30% of ears with tumor and that the presence of transitory evoked otoacoustic emissions is associat…
Progress in electron microscopic diagnostics: semi-quantitative determination of precipitable calcium in different cell types of the organ of Corti i…
1991
Potassium antimonate was used to precipitate calcium in the cochlea of the guinea-pig. The distribution of the calcium antimonate precipitates was analysed by electron microscopy. The precipitate density was determined in different cell types in the organ of Corti by counting the number of calcium binding sites in a 10-micron 2 area. The size of the precipitates varied considerably, and thus the relative amount of the precipitable calcium was estimated only semi-quantitatively. As the prominent carbon signal is superimposed over the nearby small Ca(2+)-edge signals, the combined signal of the antimony M4,5-edge and the oxygen K-edge of the calcium antimonate salt formed was chosen for the s…