Closed-loop Vagus Nerve Stimulation Parameter Optimization

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Solution Overview

Problem

Current Vagus Nerve Stimulation (VNS) therapies for refractory major depressive disorder (MDD) and temporal lobe epilepsy (TLE) face challenges in optimizing stimulus parameters, leading to variable efficacy and side effects, with a lack of understanding of the underlying pathophysiology and reproducible biomarkers for depression.

Innovation Solution

A closed-loop system using symptom- or disorder-linked biomarkers for real-time stimulus parameter optimization, predicting electrical pulse durations and amplitudes to activate specific nerve fiber groups, and an automated VNS stimulator that adjusts parameters based on recruitment patterns without biomarker sensing, improving therapeutic efficacy and reducing invasive procedures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional VNS therapy uses fixed stimulus parameters, then the device operation is simple, but the therapeutic efficacy is variable and not optimized for individual patients

Engineering Contradiction:
Improvetherapeutic efficacyVSAvoidstimulus parameter optimization system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system performs self-calibration by automatically determining optimal stimulus parameters through neural signal analysis without requiring manual physician adjustment. The processor autonomously analyzes recorded neural signals, identifies fiber type-specific patterns, and configures stimulation parameters to activate target fibers, enabling the device to optimize its own operation based on individual patient physiology.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system records neural signals during stimulation, analyzes these signals to determine which nerve fibers are being activated, and uses this feedback information to adjust and optimize stimulus parameters. This closed-loop approach ensures that the stimulation parameters are continuously refined based on actual neural response, improving therapeutic efficacy while maintaining automated operation.

Inventive Principle:
Principle #23Feedback

2Reliability

If VNS therapy uses high intensity stimulation to ensure therapeutic effect, then the efficacy is improved, but side effects increase

Engineering Contradiction:
Improvetherapeutic efficacyVSAvoidside effects
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system selectively activates specific nerve fiber types (A-fibers, B-fibers, or C-fibers) based on the therapeutic condition being treated, rather than stimulating all fiber types uniformly. By analyzing neural signals to identify fiber-specific activation patterns and tailoring stimulus parameters to target only the relevant fiber type, the system achieves condition-specific therapy with minimized off-target effects and reduced side effects.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system dynamically adjusts stimulus parameters (amplitude, pulse width, frequency) based on the identified nerve fiber type and desired therapeutic outcome. Rather than using fixed high-intensity stimulation, the processor optimizes parameters to achieve effective activation of target fibers at the lowest necessary intensity, thereby improving efficacy while minimizing harmful effects.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If manual calibration of VNS parameters is performed by physicians, then the device complexity is low, but the time required for optimization increases and consistency decreases

Engineering Contradiction:
Improveparameter optimization speedVSAvoidautomated calibration system
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system replaces the manual mechanical adjustment process with an automated computational system. The processor analyzes neural signals, applies algorithms to identify fiber type-specific patterns, and automatically configures stimulation parameters without requiring manual intervention. This substitution of manual calibration with automated signal processing and decision-making algorithms dramatically reduces optimization time while maintaining or improving consistency.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The device performs self-calibration by autonomously determining optimal stimulus parameters through neural signal analysis. The system records neural responses, processes these signals to identify activation patterns, and automatically configures stimulation parameters without requiring external physician input, thereby eliminating time-consuming manual calibration processes.

Inventive Principle:
Principle #25Self-service

4Measurement precision

If VNS therapy requires invasive procedures for parameter adjustment, then the measurement precision can be high, but the patient discomfort and risk increase

Engineering Contradiction:
Improvenerve fiber activation measurementVSAvoidinvasive procedure risks
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The system uses recorded neural signals as an intermediary to indirectly assess nerve fiber activation without requiring invasive measurement procedures. By analyzing the electrical signals naturally produced by activated neurons, the system achieves high measurement precision through non-invasive electrophysiological monitoring, eliminating the need for surgical exposure or invasive sensing of nerve fibers.

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

Enhances the efficacy of VNS therapy by autonomously optimizing stimulus parameters, providing predictable and reproducible therapeutic outcomes for refractory MDD and TLE, with potential for reduced side effects and prolonged treatment duration without the need for invasive recalibration.

Implementation Method 1

a vagus nerve stimulator to apply electrical stimulation to a patient's left cervical vagus nerve

Methodology Applied
Scientific EffectElectrical stimulation: Electrical Impedance Tomography

Implementation Method 2

to record evoked compound action potentials (CAPs) from the vagus nerve rostral to the stimulation site

Methodology Applied
Scientific EffectElectrical signal detection: Electrical Impedance Tomography

Data Source

PatentUS10335547B2Method and apparatus for closed-loop control of nerve activation
Publication Date: 2019.07.02 PURDUE RES FOUND
  • US10335547B2 patent drawing
  • US10335547B2 patent drawing
  • US10335547B2 patent drawing

AI summary

The present disclosure is directed to a method and apparatus to autonomously stimulate a plurality of nerve fiber groups. The method and apparatus predicts stimulus parameters that can activate 0-100% of the nerve fiber groups selectively according to a patient's characteristics and proportional to therapeutic outcomes, such as determined by experimental data. The method and apparatus may further be configured to input experimental third-party data to obtain a high efficacy from a patient without invasive neurosurgery.