Clemens M. Zierhofer

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Eight cochlear implant users with near-normal hearing in their non-implanted ear compared pitch percepts for pulsatile electric and acoustic pure-tone stimuli presented to the two ears. Six subjects were implanted with a 31-mm MED-EL FLEX(SOFT) electrode, and two with a 24-mm medium (M) electrode, with insertion angles of the most apical contacts ranging(More)
OBJECTIVES To assess the subjective and objective performance of the new fine structure processing strategy (FSP) compared to the previous generation coding strategies CIS+ and HDCIS. METHODS Forty-six adults with a minimum of 6 months of cochlear implant experience were included. CIS+, HDCIS and FSP were compared in speech perception tests in noise,(More)
This paper presents a geometric approach for the enhancement of the coupling coefficient between two magnetically coupled coils. It is demonstrated that the coupling coefficient can be considerably enhanced, if the turns of the coils are not concentrated at the circumferences, but distributed across the diameters. For analysis, each of the two coils is(More)
A comprehensive description of a linear model of an axon of infinite length exposed to an external voltage is presented. The steady-state transmembrane potential is derived as a function proportional to the convolution product of the second spatial difference sn of the external potential (the "activating function") and the impulse response psin of a spatial(More)
CONCLUSION Amplitude weighting using the bell-shaped filter design within the OPUS speech processors allows the creation of pitches intermediate to those of two adjacent electrodes. This mechanism can be used for both sequential and simultaneous stimulation. OBJECTIVES This paper describes frequency discrimination experiments which are based on amplitude(More)
A 12-channel cochlear implant (CI) for high-rate pulsatile stimulation strategies is presented. Symmetric biphasic current pulses can be generated up to a maximum pulse repetition rate of 18.18 kpulses/second. The stimulation pulse amplitude can be selected within 1.5 microA-1.5 mA. Data and power are transcutaneously transferred using a single(More)
A closed-form deterministic description of the quantization noise introduced by an infinite uniform quantizer as a function of an arbitrary input signal is given. The quantization noise can be regarded as a superposition of frequency-modulated (FM) sinusoids. For a band-limited Gaussian noise input signal, the power density spectrum of the quantization(More)
We present an algorithm for the estimation of fundamental frequencies in voiced audio signals. The method is based on an autocorrelation of a signal with a segment of the same signal. During operation, frequency estimates are calculated and the segment is updated whenever a period of the signal is detected. The fast estimation of fundamental frequencies(More)
BACKGROUND Modern cochlear implants have integrated recording systems for measuring electrically evoked compound action potentials of the auditory nerve. The characterization of such recording systems is important for establishing a reliable basis for the interpretation of signals acquired in vivo. In this study we investigated the characteristics of the(More)