Visual Prosthesis Fitting via Electrically Evoked Responses

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Solution Overview

Problem

Existing visual prostheses require manual adjustment to individual patient neural characteristics, which becomes tedious and impractical with increasing numbers of active electrodes, and existing automatic fitting techniques are expensive and inefficient.

Innovation Solution

A method using electrically evoked electroretinogram (eERG) responses to determine the minimum and maximum stimulation levels for each electrode, incorporating noise filtering and wavelet transforms to accurately measure neural activity and automate the fitting process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If manual adjustment is used to fit visual prosthesis to individual patient neural characteristics, then the fitting can be customized to patient needs, but the process becomes tedious and impractical with increasing numbers of active electrodes

Engineering Contradiction:

Improvecustomization to patient neural characteristicsVSAvoidfitting time

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The system performs automatic fitting by having the patient provide simple visual responses (e.g., looking at LEDs) while the system automatically adjusts stimulation parameters based on detected neural responses, eliminating the need for tedious manual adjustment by clinicians

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system uses real-time feedback from electrically evoked retinal responses (EERs) to automatically adjust stimulation parameters, creating a closed-loop system that adapts to individual patient neural characteristics without manual intervention

Inventive Principle:

Principle #23Feedback

2Extent of automation

If existing automatic fitting techniques are used, then the fitting process is automated, but the techniques are expensive and inefficient

Engineering Contradiction:

Improveautomation of fitting processVSAvoidfitting efficiency

Core Design Contradiction:

Extent of automationVSProductivity

Solution Approach 1:

The system replaces complex mechanical and manual adjustment procedures with a simplified electronic system that uses basic visual response detection and automated algorithmic adjustment, achieving both automation and efficiency

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system automatically adjusts stimulation parameters (intensity, duration, frequency) based on detected neural responses, enabling efficient adaptation to individual patient characteristics without expensive equipment or lengthy procedures

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11019991B2Method and apparatus for fitting a visual prosthesis using electrically evoked responses

Publication Date: 2021.06.01 CORTIGENT INC

AI summary

The invention is a method of automatically adjusting a visual prosthesis electrode array to the neural characteristics of an individual patient. By recording electrically evoked responses to a predetermined input stimulus, one can alter that input stimulus to the needs of an individual patient. A minimum input stimulus is applied to a patient, followed by recording an electrically evoked response to the input stimulus. By gradually increasing stimulus levels, one can determine the minimum input that creates a neural response, thereby identifying the threshold stimulation level. One can further determine a maximum level by increasing stimulus until a predetermined maximum neural response is obtained.