Cochlear Implant Stimulation Using Simultaneous Sign-Correlated Pulses

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Solution Overview

Problem

Current cochlear implant technologies face limitations in power consumption and voltage requirements due to high interface impedances, which restrict the efficiency of electrical nerve stimulation, particularly in multi-channel configurations where simultaneous stimulation is not effectively utilized to reduce power and voltage needs.

Innovation Solution

The method involves determining amplitudes for simultaneous, sign-correlated pulses across multiple electrodes in a monopolar electrode configuration to achieve desired potentials with reduced power consumption, utilizing channel interaction compensation to ensure constructive superposition of electrical fields and minimize voltage drops across interface impedances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If continuous-interleaved-sampling strategy is used with high overall stimulation rate, then temporal representation of envelope signal is adequate, but power consumption increases and voltage requirements rise due to high interface impedances

Engineering Contradiction:
Improvetemporal representation accuracyVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent combines multiple stimulation channels into simultaneous stimulation groups, where channels are stimulated together rather than sequentially. This merging approach reduces the overall number of stimulation events required, thereby reducing power consumption while maintaining adequate temporal representation of the envelope signal.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent dynamically adjusts stimulation parameters by implementing channel interaction compensation that adapts to the electrical fields generated by simultaneous channels. This dynamic adjustment allows for reduced voltage amplitudes in simultaneous stimulation while maintaining the desired temporal fidelity, thus reducing power consumption.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If continuous-interleaved-sampling strategy is used with high overall stimulation rate, then temporal representation of envelope signal is adequate, but voltage requirements increase due to high interface impedances

Engineering Contradiction:
Improvetemporal representation accuracyVSAvoidvoltage requirements
Core Design Contradiction:
Measurement precisionVSPower

Solution Approach 1:

By merging multiple channels into simultaneous stimulation groups, the patent reduces the total number of stimulation events, which directly reduces the cumulative voltage requirements across the interface impedance, lowering the peak voltage demands on the power supply.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the stimulation parameter from sequential to simultaneous activation, and implements channel interaction compensation that adjusts voltage amplitudes based on the superposition of electrical fields. This parameter change allows achieving the same neural stimulation effect with lower voltage requirements.

Inventive Principle:
Principle #35Parameter changes

3Use of energy by moving object

If simultaneous stimulation of multiple channels is implemented, then power consumption is reduced, but electrical field superposition and channel interaction must be compensated

Engineering Contradiction:
Improvepower consumptionVSAvoidchannel interaction compensation
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent implements channel interaction compensation that acts as a feedback mechanism, where the electrical fields generated by simultaneously stimulated channels are measured and compensated for in subsequent stimulation events. This feedback approach maintains stimulation accuracy while enabling power-reducing simultaneous stimulation.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent performs preliminary calculations of channel interactions and electrical field superpositions before actual simultaneous stimulation occurs. By pre-computing the compensation factors, the system reduces the complexity of real-time control while maintaining the benefits of simultaneous stimulation.

Inventive Principle:
Principle #10Preliminary action

4Reliability

If sequential stimulation is used in CIS strategy, then channel interaction is minimized, but stimulation rate per channel must be high to maintain overall information rate

Engineering Contradiction:
Improvechannel independenceVSAvoidstimulation rate per channel
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent inverts the conventional CIS approach by implementing simultaneous instead of sequential stimulation. This inversion allows channels to work together rather than take turns, reducing the stimulation rate per channel while maintaining or improving overall information transmission through coordinated channel interaction compensation.

Inventive Principle:
Principle #13The other way round (Inversion)

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 reduces stimulation power and voltage requirements by up to 23% compared to traditional continuous-interleaved-sampling strategies, enabling more efficient and effective electrical nerve stimulation while maintaining desired potential levels.

Implementation Method 1

determining amplitudes of simultaneous, sign-correlated pulses associated with at least two electrodes... to provide a total potential at a given position that is substantially equal to a desired potential

Methodology Applied
Scientific EffectSuperposition of electrical fields: Electric Field

Implementation Method 2

The stimulator 105 generates the stimulation patterns and conducts them to the nerve tissue by means of an electrode array 107

Methodology Applied
Scientific EffectElectrical conduction through tissue: Conduction (electrical)

Implementation Method 3

high interface impedances, which restrict the efficiency of electrical nerve stimulation

Methodology Applied
Scientific EffectElectrical impedance: Electrical Resistance

Data Source

PatentEP2364749B1Simultaneous stimulation for low power consumption
Publication Date: 2015.10.21 MED EL ELEKTROMEDIZINISCHE GERAETE GMBH
  • EP2364749B1 patent drawingFigure 1
  • EP2364749B1 patent drawingFigure 2
  • EP2364749B1 patent drawingFigure 3

AI summary

A stimulation system including a stimulator having a multi-channel electrode array utilizing a monopolar electrode configuration. A processor is operatively coupled to the stimulator. The processor is configured to determine a channel interaction (CI) sequence using simultaneous, sign-correlated pulses and channel interaction compensation. The CI sequence has a CI pulse rate and a CI mean pulse amplitude, and produces resulting potentials that are substantially equal to desired potentials at given positions relative to the multi-channel array. The CI sequence may include temporal gaps between pulses, wherein the processor may be configured to increase the CI pulse rate, such that the temporal gap between pulses is decreased. Furthermore, the processor may be configured to reduce the pulse amplitude of the CI sequence while increasing pulse phase duration, such that charge per pulse remains substantially unchanged and the temporal gap between pulses is decreased.