Modern cochlear implant systems deliver impulse transmission rates up to 50,000 pps. It emerged that the fast stimulation rates led to enhanced speech comprehension. Impedance measurement is an important aspect in cochlear implant testing procedures. Impedance values are a measure of the electrical resistance between the individual implant electrodes. Increased impedances were attributed frequently to inflammatory/tissue-related processes. In recent years, however, we have repeatedly found cases of impedance increase for which the inflammatory model did not provide a satisfactory explanation. The aim of this study is to evaluate increases in impedance in our cochlear implant population, to attempt to find their cause, and to formulate therapeutic hypotheses. In our cochlear implant programme (> 3000 recipients) we screened our database for impedance increases over time during device fitting. We found 16 patients with 18 affected ears in whom impedance increases were clearly demonstrated. We found that especially in cases without any sign of prior inflammation, increasing the pulse width of the stimulation strategy seems to be an effective tool to return increased impedances to normal levels.

Purpose: The evaluation of long-term results of cochlear implantation in patients with typical Cogan syndrome. Procedures: The medical records of approximately 3,000 patients who underwent cochlear implantation in a tertiary centre within the period 1992–2007 were retrospectively examined. Results: Four cochlear implant recipients with Cogan syndrome (6 implantations) were identified. One cochlea was found to be partially obliterated; the electrode could, however, be completely inserted. Wound healing disorders and infections in a patient with systemic symptoms were the only postoperative complications. Hearing outcome was favorable, with average HSM and monosyllabic scores of 96.7 and 82.5%, respectively, in an average follow-up time of 9.25 years. Conclusions: Cochlear implantation is the appropriate hearing rehabilitation method in Cogan syndrome patients. Although the basic illness does not affect the long-term hearing outcome, skin-atrophy-related complications in cases with systemic symptoms may occur. Finally, the cochlear implant surgeon should be aware of the possible cochlea obliteration.

The PSS presents a risk for cochlear implant surgery that can be detected by the neuroradiologist in advance. Venous CT angiography is advisable in certain cases. The previous assumption that a persistent PSS is encountered more frequently in cases of skull base deformity can be affirmed in the special situation of complete aplasia of the SCCs.

A new straight thin electrode array (universal electrode) was designed to be used together with a positioner, which will place the electrode array at the medial wall (modiolus) of the cochlea. The study objectives were to demonstrate safety and ease of insertion, tissue trauma, electrode position, and depth for universal and standard electrodes in human temporal bones; to test functional properties in cats; and to determine the surgical procedure and electrophysiological benefits in a clinical study. The cadaver study demonstrated the ease of insertion for the universal electrode and the positioner without tissue damage. An average gain of insertion depth of 180° was achieved with the positioner. Animal studies demonstrated a reduction in threshold of 6 dB for the electrical auditory brain stem response (EABR). Neither additional cochlear damage nor additional connective tissue formation was found. The intraoperative human study findings showed a marked reduction of threshold for both EABR and stapedius reflex thresholds. Impedances were increased. Plain x-rays demonstrated modiolus proximity of the electrode with the positioner. The new Clarion electrode with positioner is a relatively safe design for providing modiolus proximity. The electrophysiological benefits include reduction of threshold and power consumption.. j

Cochlear implantation is the proper method for optimal hearing rehabilitation in patients with Pendred syndrome. Although the precise pathogenetic mechanism and the genetic background of deafness in Pendred syndrome have not been completely understood, the preexisting hearing experience represents a positive factor for satisfying hearing outcome. The inner-ear malformations can cause mild surgical difficulties and extended surgery duration. The cochlear implant surgeon should be aware of these difficulties to avoid complications.