Cochlear Implant Current Spread Decay Parameter Fitting
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Solution Overview
Problem
Cochlear implant systems face challenges in optimizing patient-specific fitting parameters for simultaneous electrode stimulation, leading to spatial channel interaction and suboptimal sound perception, as existing methods rely on arbitrary decay constants or subjective patient feedback.
Innovation Solution
A system and method for determining patient-specific current spread decay parameters through psychoacoustic and objective measurements, such as ECAP and telemetry voltage analysis, to adjust stimulation patterns and minimize channel interaction, ensuring similar sound perception between sequential and simultaneous stimulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If simultaneous stimulation of multiple electrode contacts is used, then sound perception quality is improved, but spatial channel interaction occurs causing suboptimal perception
Solution Approach 1:
The patent applies parameter changes by adjusting the decay constants (alpha and beta) in the exponential decay model to account for current spread characteristics. By modifying these parameters based on patient-specific measurements, the system compensates for spatial channel interaction while maintaining simultaneous stimulation benefits, thus resolving the contradiction between improved sound perception and harmful channel interaction
Solution Approach 2:
The patent implements feedback through patient-specific objective measurements (ECAP or telemetry voltages) that are used to determine individual decay parameters. This feedback loop allows the system to adapt the stimulation parameters to the specific patient's cochlear characteristics, enabling simultaneous stimulation while compensating for spatial channel interaction effects
2Device complexity
If arbitrary decay constants are used for channel interaction compensation, then device complexity is reduced, but patient-specific optimization is lost
Solution Approach 1:
The patent applies self-service by enabling the system to automatically determine patient-specific decay parameters through objective measurements (ECAP or telemetry voltages) without requiring subjective patient feedback. The system performs self-calibration by measuring electrical characteristics and computing individualized parameters, thus maintaining simplicity while achieving patient-specific optimization
Solution Approach 2:
The patent replaces the traditional mechanical/subjective fitting process with an electrical measurement-based approach. Instead of relying on subjective patient feedback or arbitrary constants, the system uses objective electrical measurements (ECAP or telemetry voltages) to determine decay parameters, substituting electrical characterization for traditional fitting methods
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The approach allows for precise adjustment of decay parameters to match sound perception in both stimulation modes, improving sound reception and speech clarity by using patient-specific values for current spread decay constants.
Implementation Method 1
a cochlear implant with an implanted electrode contact can electrically stimulate auditory nerve tissue with small currents delivered by multiple electrode contacts distributed along the electrode
Implementation Method 2
the fluid-filled cochlea 104 functions as a transducer to generate electric pulses which are transmitted to the cochlear nerve 113
Implementation Method 3
an objective measurement of MCLs and THLs is based on the measurement of the ECAPs (Electrically Evoked Compound Action Potentials)
Data Source
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AI summary
Approaches are described for fitting a simultaneous stimulation arrangement of a cochlear implant system to an implanted patient. Electrode contacts in an electrode array implanted in a patient cochlea are stimulated with a fitting pattern of stimulation signals. Then current spread decay parameters are determined for patient specific amplitude compensation of the simultaneous stimulation arrangement based on either a psychoacoustic aspect or an objective measurement of patient percept to the fitting pattern.