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This study introduces and evaluates a method for measurement of the longitudinal spread of electrically evoked neural excitation in the cochlea, using the Neural Response Telemetry system (NRT) available with the Nucleus((R)) 24 cochlear implant system. The recently released version of the NRT software (version 3.0) enables presentation of the 'masker' and(More)
OBJECTIVE The study investigated the hypothesis that threshold and comfortable levels recorded from cochlear implant patients would reduce, and dynamic range increase, as distance of the electrode from the modiolar wall (radial distance) decreases. Two groups of cochlear implant patients participated; one group using the Nucleus' 24 Contour electrode array,(More)
The feasibility of using the electrically evoked compound action potential (ECAP), measured with the NRT system (Neural Response Telemetry) and the NRT software (version 2.04), to quantify the longitudinal spread of neural excitation was examined in four subjects fitted with the Nucleus C124M cochlear implant. The ECAP and psychophysical forward-masking(More)
Psychophysical measurements were performed in three hearing-impaired adult subjects implanted with a CI22 cochlear prosthesis (Cochlear Ltd.) fitted with a developmental peri-modiolar electrode array. The array was manufactured with a curvature approximating that of the inner wall of the scala tympani but, after straightening and insertion, lay on average(More)
The objective of this study was to compare the psychophysical performance of patients using the Nucleus Contour electrode array with that of patients using the straight banded-electrode array. In particular, we wished to consider how psychophysical parameters would differ for an electrode array positioned closer to the modiolus, and how this might influence(More)
OBJECTIVE The aim of these studies was to investigate the insertion properties and safety of a new intracochlear perimodiolar electrode array design (Contour). BACKGROUND An electrode array positioned close to the neural elements could be expected to reduce stimulation thresholds and might potentially reduce channel interaction. METHODS Two sequential(More)
The effect on coronal leakage of the use of either a single gutta-percha cone or cold lateral condensation of gutta-percha, with a glass ionomer sealer cement was studied. In addition, the effect of the removal of the smear layer was also determined. Eighty-eight single-rooted teeth were prepared chemomechanically using hand files, with the balanced force(More)
The heat generated on the external root surface of human premolar teeth during post space preparation was measured in vitro. The rise in temperature was recorded at a point 6 mm from the apex of the tooth using a thermocouple attached to a chart recorder. The temperature rise was greatest when the removal of gutta-percha was combined with post channel(More)
The effect of post space preparation on the apical seal of teeth roots treated with the plastic-cored Thermafil was studied in vitro. Single rooted teeth with mature apices were prepared chemomechanically and obturated with alpha-phase gutta-percha, Thermafil, on plastic core-carriers and sealer, Sealapex. The teeth were divided randomly into four groups of(More)
OBJECTIVE This study describes the application of a new radiographic imaging modality, phase-contrast radiography, to in vitro human temporal bone imaging and investigates its use in the development of new electrode arrays for cochlear implants. BACKGROUND The development of perimodiolar electrode arrays for cochlear implants requires detailed information(More)