Cochlear Implant Headpiece Magnet Self-Alignment

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Solution Overview

Problem

Conventional cochlear implant systems face issues with magnetic resonance imaging (MRI) compatibility due to misalignment of magnetic fields, leading to demagnetization and tissue damage, and suffer from suboptimal retention forces causing discomfort and poor microphone alignment with the sound source.

Innovation Solution

A cochlear implant headpiece with a diametrically magnetized headpiece magnet rotatable about its axis, self-aligning with the gravitational direction, and a microphone array oriented perpendicular to the gravitational direction to maximize retention force and ensure proper sound source alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a disk-shaped magnet with axial magnetization is used in the cochlear implant, then the magnet can be easily manufactured and positioned, but the magnetic field direction becomes misaligned with the MRI magnetic field, causing demagnetization and tissue damage

Engineering Contradiction:
Improvemagnet manufacturingVSAvoidMRI compatibility
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent changes the magnetization direction parameter from axial to diametric, and makes the magnet rotatable to change its orientation parameter dynamically. This allows the magnet to be MRI-compatible by rotating into alignment with the MRI magnetic field while maintaining ease of manufacture through standard disk-shaped geometry

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If the headpiece magnet is fixed in position, then the device structure is simplified, but the lateral retention force is reduced and the microphone array may not align properly with the sound source

Engineering Contradiction:
Improveheadpiece structureVSAvoidlateral retention force
Core Design Contradiction:
Device complexityVSForce

Solution Approach 1:

The patent makes the headpiece magnet rotatable about its axis, transforming it from a static component to a dynamic one. This rotation capability allows the magnet to self-align with the gravitational direction, maximizing lateral retention force while keeping the overall device structure relatively simple

Inventive Principle:
Principle #15Dynamics

3Force

If the headpiece magnet is allowed to rotate freely, then the lateral retention force is maximized, but the magnet may become misaligned with the implant magnet, reducing retention and causing discomfort

Engineering Contradiction:
Improvelateral retention forceVSAvoidmagnet alignment
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The patent employs magnetic attraction as a feedback mechanism where the interaction between the headpiece magnet and implant magnet provides natural alignment guidance. The magnets attract each other and self-align, creating a stable equilibrium position that maintains reliable retention while allowing the headpiece magnet to rotate for optimal lateral force

Inventive Principle:
Principle #23Feedback

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 solution enhances the lateral retention force and ensures the microphone array points towards the sound source effectively, regardless of the headpiece orientation, while maintaining compatibility with MRI systems by aligning the magnet's N-S direction with the gravitational direction.

Implementation Method 1

A diametrically magnetized headpiece magnet, defining an axis and a N-S direction, rotatable about the axis, with the N-S direction self-aligning with the gravitational direction when the axis is perpendicular to the gravitational direction

Methodology Applied
Scientific EffectGravitation: Gravitation

Implementation Method 2

The headpiece and the cochlear implant may include respective magnets (or respective pluralities of magnets) that are attracted to one another, thereby retaining the headpiece on the head and maintaining the position of the headpiece transmitter on the head over the implant receiver

Methodology Applied
Scientific EffectMagnetic attraction: Magnetism

Implementation Method 3

The magnet 22 will rotate about the axis A into alignment with an MRI magnetic that is perpendicular to the axis A

Methodology Applied
Scientific EffectMagnetic field alignment: Magnetic Field

Data Source

PatentEP4008397B1Headpieces and implantable cochlear stimulation systems including the same
Publication Date: 2023.09.13 ADVANCED BIONICS AG
  • EP4008397B1 patent drawingFigure 1~5
  • EP4008397B1 patent drawingFigure 6~9
  • EP4008397B1 patent drawingFigure 10~14

AI summary

There is provided a cochlear implant headpiece for use with a cochlear implant, the cochlear implant headpiece comprising: a first headpiece portion defining a rotational axis; a second headpiece portion mounted on the first headpiece portion and rotatable relative to the first housing portion about the rotational axis, including a headpiece antenna and first and second microphones defining a microphone array axis, and having a center of gravity located such that the microphone array axis will be perpendicular to the gravitational direction when the rotational axis is perpendicular to the gravitational direction; and a headpiece magnet associated with the first headpiece portion.