Implantable Hearing Prosthesis Signal Cancellation in MRI Fields

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Solution Overview

Problem

Individuals with conductive hearing loss, who are not candidates for cochlear implants, often do not benefit sufficiently from hearing aids due to chronic inflammation or malformed ear structures, and are also at risk of adverse effects from magnetic fields during procedures like MRI.

Innovation Solution

An implantable hearing prosthesis is designed to mitigate or cancel signals induced by external magnetic fields, allowing it to function differently and reduce or eliminate unwanted hearing perceptions, using a feedback or feedforward mechanism to counteract induced voltages.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a hearing aid is used to transmit acoustic signals to the cochlea, then sound perception is improved, but the device becomes vulnerable to adverse effects from external magnetic fields during MRI procedures

Engineering Contradiction:
Improvehearing perceptionVSAvoidadverse effects from magnetic fields
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies the principle of converting harm into benefit by using the external magnetic field's induced voltage to drive the electromagnetic actuator in a controlled manner. The harmful induced voltage from MRI is transformed into a useful driving force that can be harnessed to provide hearing stimulation during the procedure, turning a harmful effect into a beneficial one.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the operational parameters of the hearing aid by switching from acoustic transmission to electromagnetic actuation when exposed to magnetic fields. The system detects the presence of a magnetic field and transitions to using electromagnetic forces generated by the induced voltage to drive the actuator, thereby adapting to the changing environmental conditions and maintaining functionality.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If an electromagnetic actuator is used in the hearing prosthesis, then the device can function without acoustic pathways, but the actuator becomes susceptible to induced signals from external magnetic fields

Engineering Contradiction:
Improvefunctionality in diverse ear conditionsVSAvoidsignal interference from magnetic fields
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements feedback control by monitoring the electrical signals generated by the electromagnetic actuator and using this information to adjust the drive signals accordingly. The system detects induced voltages from external magnetic fields and modifies its output to compensate for these disturbances, ensuring stable and reliable operation despite the presence of external magnetic interference.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent introduces an intermediary signal processing stage that acts as a mediator between the external magnetic field and the actuator. This intermediary system includes signal conditioning circuits that filter, amplify, and process the induced voltages, transforming them into controlled drive signals that reliably activate the actuator without direct interference from external magnetic fields.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 prosthesis effectively reduces or eliminates undesired hearing perceptions caused by magnetic fields, enhancing its functionality and compatibility with MRI procedures.

Implementation Method 1

This hearing prosthesis, commonly referred to as a middle ear implant, converts received sound into a mechanical force that is applied to the ossicular chain or directly to the cochlea via an actuator implanted in or adjacent to the middle ear cavity

Methodology Applied
Scientific EffectElectromagnetic force: Lorentz Force

Implementation Method 2

an implantable hearing prosthesis is designed to mitigate or cancel signals induced by external magnetic fields

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3930826B1Prosthesis operation in the face of magnetic fields
Publication Date: 2026.02.25 COCHLEAR LIMITED
  • EP3930826B1 patent drawingFigure 1
  • EP3930826B1 patent drawingFigure 2A
  • EP3930826B1 patent drawingFigure 2B

AI summary

An apparatus, including an implantable portion of a hearing prosthesis, wherein the apparatus is configured to at least partially cancel a signal in the implantable portion, the signal resulting from an external magnetic field generated external to a recipient of the hearing prosthesis. In an exemplary embodiment, the signal is a signal generated by the external magnetic field interacting with an electrical lead extending between a stimulation output device of the prosthesis and a stimulator and/or receiver of the implantable portion.