Med-el Elektromedizinische Geraete Gmbh

Konrad Eugen Schwarz

Stefan Strahl

Philipp Spitzer

Angelika Dierker

Martin Franz Goll

A system and method detect neuronal action potential signals from tissue responding to electrical stimulation signals. A sparse signal space model for a set of tissue response recordings has a signal space separable into a plurality of disjoint component manifolds including a neural action potential (NAP) component manifold corresponding to tissue response to electrical stimulation signals. A response measurement module is configured to: i. map a tissue response measurement signal into the sparse signal model space to obtain a corresponding sparse signal representation, ii. project the sparse signal representation onto the NAP component manifold to obtain a sparse NAP component representation, iii. when the sparse NAP component representation is greater than a minimum threshold value, report and recover a detected NAP signal in the tissue response measurement signal.

Detecting neuronal action potentials using a sparse signal representation

A hearing implant fitting system includes a physiological database containing physiological data characterizing auditory neural tissue response to electrical stimulation. A neural action potential (NAP) measurement system measures NAP signals from cochlear tissue responding to electrical stimulation signals delivered by one or more of the electrode contacts, including: deriving a compound discharge latency distribution (CDLD) of the cochlear tissue by deconvolving: (1) a tissue response measurement signal taken responsive to the delivered electrical stimulation signals, with (2) an elementary unit response signal representing voltage change at a measurement electrode contact due to the electrical stimulation, and then comparing the CDLD to physiological data from the physiological database to detect an NAP signal from the tissue response measurement signal. A fitting display provides to the fitting audiologist a visual display representing the CDLD and the NAP signal for fitting the electrode array to an implanted patient.

Detecting neuronal action potentials using a convolutive compound action potential model

A method of fitting a cochlear implant in an ipsilateral ear of a subject, the cochlear implant having an electrode array with one or more electrode contacts, includes applying broad-band white noise stimulus to a contralateral ear in order to mask efferent nerve fibers, applying a single pulse stimulus to the ipsilateral ear and then measuring base-line evoked compound action potential (CAP) signals in the ipsilateral ear for an electrode contact during a refractory period, applying a sequence of separated single pulse stimuli to the contralateral ear and then measuring attenuated CAP signals in the ipsilateral ear for the electrode contact during the refractory period, comparing the measured attenuated CAP signals to the measured base-line CAP signals in order to determine a CAP threshold for the electrode contact and adjusting processing parameters of the cochlear implant based on the CAP threshold.

Cochlear implant fitting via efferent nerve fibers

A system for frequency matching a cochlear implant during fitting includes a tissue stimulation device configured to generate a tonal stimulus to mask efferent nerve fibers in a subject, one or more response measurement contacts configured to measure CAP signals during and outside of a refractory period, a frequency matching module in communication with the response measurement contacts and configured to receive the CAP signals during and outside of the refractory period to determine a stimulation location on the cochlear implant based on a comparison of the received CAP signals both during and outside of the refractory period, and a parameter adjusting module in communication with the frequency matching module and configured to interface with the cochlear implant and to adjust its processing parameters based on the stimulation location. Methods for frequency matching a cochlear implant during fitting are also disclosed.

Arrangements are described for determining a physiological characteristic of the auditory pathway (as whole or selected parts such as an inner ear). Electrical stimulation pulses are delivered to inner ear neural tissue and corresponding tissue response signals are developed by measuring over time response of the auditory pathway to each electrical stimulation pulse, with each tissue response signal forming a response curve including at least one physiological landmark such as a local maximum and a local minimum. A multi-dimensional polynomial is fit over the tissue response signals, and calculation starting points are defined based on prominent physiologic landmarks such as a local maximum and a local minimum for one selected tissue response signal. A line of minimum principal curvature of the multi-dimensional polynomial over the plurality of tissue response signals that intersect the calculation starting points is calculated to determine a physiological characteristic of the auditory pathway.

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Axams, Austria

Konrad Eugen Schwarz