Implantable Telemetry Receiver Noise Rejection During Therapy

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Solution Overview

Problem

Existing implantable medical devices face challenges in receiving telemetry signals during electrical stimulation therapy due to noise interference, which can disrupt therapy and require prolonged interruptions for communication, especially at high pulse rates like those in neurostimulators.

Innovation Solution

A system with a true differential input receiver and common mode filtering, combined with diodes for full wave rectification and a logarithmic front end, allows for simultaneous telemetry communication during electrical stimulation therapy by minimizing noise interference and increasing signal strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If telemetry receiver is turned on between electrical stimulation pulses to receive telemetry signals, then telemetry communication is enabled, but electrical stimulation therapy must be interrupted which causes side effects to return

Engineering Contradiction:

Improvetelemetry communication reliabilityVSAvoidpatient side effects

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent enables continuous electrical stimulation therapy delivery without interruption while simultaneously receiving telemetry signals. The receiver operates continuously during therapy delivery, eliminating the need to stop therapy for telemetry communication, thus maintaining continuous therapeutic action and preventing side effects from returning.

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The patent converts the harmful noise from electrical stimulation pulses into a benefit by using the same noisy period for telemetry reception. Instead of stopping therapy to receive telemetry, the system utilizes the therapy pulse timing to enable telemetry communication, transforming the previously harmful interference into a useful signal reception opportunity.

Inventive Principle:

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

2Productivity

If telemetry is attempted during high rate electrical stimulation therapy (260 Hz or higher), then concurrent therapy and telemetry are enabled, but data rate is greatly diminished due to noise interference

Engineering Contradiction:

Improveconcurrent therapy and telemetry capabilityVSAvoidtelemetry data rate

Core Design Contradiction:

ProductivityVSLoss of information

Solution Approach 1:

The patent changes the receiver operating parameters to operate during the high-rate stimulation therapy periods. By adjusting the receiver timing and synchronization to match the 260 Hz or higher pulse rate, the system enables concurrent operation while managing the reduced data rate through optimized reception windows and signal processing.

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If telemetry receiver is turned off during electrical stimulation pulses to avoid noise, then noise interference is reduced, but telemetry communication cannot occur during therapy

Engineering Contradiction:

Improvenoise interference levelVSAvoidtelemetry communication availability

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent maintains continuous receiver operation during electrical stimulation therapy, eliminating the need to turn the receiver off and on. This continuous operation ensures telemetry communication availability throughout therapy delivery while managing noise through signal processing rather than receiver shutdown.

Inventive Principle:

Principle #20Continuity of useful action

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

Enables reliable bi-directional transcutaneous telemetry without interrupting electrical stimulation therapy, reducing potential side effects and ensuring successful communication even in noisy environments.

Implementation Method 1

The receiver used in an embodiment of the present invention provides a true differential input receiver and has extremely good common mode noise rejection. Common mode filtering was accomplished by splitting a single parallel tank tuning capacitor into two series capacitors with the midpoint referenced to ground.

Methodology Applied

Scientific EffectCommon mode filtering:

Implementation Method 2

Diodes are placed in parallel to the split capacitors for full wave rectification while providing a reference to ground and input circuit protection.

Methodology Applied

Scientific EffectFull wave rectification: Diode

Implementation Method 3

A logarithmic front end is used to increase the signal to noise ratio (which allows a higher success to communicate rate in a noisy environment by moving the programming head closer to the device)

Methodology Applied

Scientific EffectLogarithmic amplification:

Data Source

PatentUS8428712B2Concurrent delivery of treatment therapy with telemetry in an implantable medical device

Publication Date: 2013.04.23 MEDTRONIC INC

AI summary

A system, method and implantable medical for concurrently providing a therapeutic output to a patient while communicating transcutaneously with an external device. The therapeutic output is provided to the patient with an implantable medical device wherein an electromagnetic signal is associated with at least one of recharging of a rechargeable power source and providing the therapeutic output. Bi-directional transcutaneous communication is conducted via via telemetry between the implantable medical device and an external device using a telemetry signal while the telemetry signal and the electromagnetic signal occur simultaneously.