Cochlear Implant Stapedius Reflex Detection via Middle Ear Pressure
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Solution Overview
Problem
Current methods for measuring the stapedius reflex in cochlear implant fitting are invasive, difficult to perform, and not suitable for chronic implantation, as they require specialized equipment and skilled personnel, and existing electrodes fail to provide reliable and atraumatic contact with the stapedius muscle.
Innovation Solution
A method using a response sensor, such as a microphone or pressure sensor, to detect the stapedius reflex by measuring subtle fluctuations in pressure response characteristics in the middle ear, without the need for tympanometry or closure of the outer ear canal, and determining the maximum comfortable level (MCL) of stimulation by comparing baseline and modified acoustic transfer functions during electrically evoked measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional tympanometry or invasive electrode contact methods are used to measure stapedius reflex, then measurement capability is achieved, but device complexity and difficulty of operation increase significantly
Solution Approach 1:
The cochlear implant system's own electrodes and signal processing capabilities are utilized to detect the stapedius reflex. The electrodes already implanted in the cochlea serve dual purposes: both stimulating auditory nerve fibers and detecting the reflex response through impedance changes, eliminating the need for separate measurement equipment.
Solution Approach 2:
The electrode array performs multiple functions: it provides electrical stimulation to the auditory nerve for hearing restoration and simultaneously acts as a sensor to detect stapedius muscle reflex through impedance measurements, combining therapy and diagnostics in a single device.
2Measurement precision
If invasive electrode contact with stapedius muscle is used, then direct measurement is achieved, but trauma and reliability issues arise
Solution Approach 1:
The measurement is performed indirectly through the middle ear ossicles and fluid pathways rather than direct contact with the stapedius muscle. Electrical stimulation causes the stapedius muscle to contract, which changes the impedance of the middle ear system, and this impedance change is detected by the electrodes without requiring direct muscle contact.
Solution Approach 2:
Direct mechanical contact with the stapedius muscle is replaced by electrical field-based impedance measurement. The system uses electrical stimulation and measures electrical impedance changes in the middle ear system, substituting mechanical intrusion with a non-contact electrical measurement method.
3Measurement precision
If existing electrode designs are used for stapedius contact, then measurement capability is achieved, but reliability and atraumatic contact cannot be maintained
Solution Approach 1:
The standard cochlear implant electrode array serves dual purposes: providing auditory stimulation and detecting stapedius reflex. This eliminates the need for specialized measurement electrodes that would require separate implantation and compromise reliability for chronic use.
Solution Approach 2:
The cochlear implant system performs its own diagnostic measurements using its existing components. The implant's electrodes and signal processing capabilities are sufficient to detect the stapedius reflex, making external specialized equipment unnecessary and ensuring long-term reliability.
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
This approach allows for a more reliable and minimally invasive measurement of the stapedius reflex, improving the accuracy of cochlear implant fitting by identifying the MCL without the need for complex equipment or skilled procedures, and enabling chronic implantation.
Implementation Method 1
A response sensor, such as a microphone or pressure sensor, to detect the stapedius reflex by measuring subtle fluctuations in pressure response characteristics in the middle ear
Data Source
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AI summary
Arrangements are described for fitting a cochlear implant to a recipient patient. An acoustic stimulus is delivered to an ear of the patient over a range of acoustic frequencies. A baseline acoustic transfer function resulting from the acoustic stimulus is measured using a response sensor configured to sense pressure response characteristics in the middle ear. And a maximum comfortable level (MCL) of stimulation is determined for at least one stimulation contact in the electrode array, based on performing an electrically evoked measurement to an electric stimulation signal and using the response sensor to measure a modified acoustic transfer function. The modified acoustic transfer function is compared to the baseline acoustic transfer function to determine when a stapedius reflex response occurs and identify the MCL.