Tissue Resistance Measurement Error Correction
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Solution Overview
Problem
Existing medical devices face challenges in accurately measuring tissue resistance due to circuit bandwidth limitations, leading to errors in determining therapy parameters for electrical stimulation, particularly in implantable devices like deep brain stimulators.
Innovation Solution
The implementation of a method that generates and processes electrical signals at different frequencies to isolate and remove error values from tissue resistance measurements, utilizing a chopper circuit and averager circuit to differentiate between resistive and reactive components, allowing for accurate determination of tissue resistance without the need for high-bandwidth amplifiers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If bandwidth limitations of the amplifier are accepted, then device complexity is reduced, but measurement precision deteriorates due to error values in tissue resistance determination
Solution Approach 1:
The patent applies parameter changes by measuring tissue resistance at multiple different frequencies rather than a single frequency. By taking measurements at frequency f1, f2, and potentially other frequencies, the system can distinguish between actual tissue resistance and error values that vary with frequency. The actual tissue resistance remains constant across frequencies while error values change, allowing the true resistance to be extracted through mathematical processing of the frequency-dependent measurements.
Solution Approach 2:
The patent implements a feedback mechanism where the measured resistance values at different frequencies are processed to identify and eliminate error components. The system uses the relationship between frequency-dependent error values and frequency-independent actual resistance to calculate corrected resistance values, feeding this corrected information back into the therapy delivery system for more accurate therapy parameter determination.
2Measurement precision
If multiple frequency measurements are performed, then measurement precision improves by removing error values, but loss of time increases due to additional processing steps
Solution Approach 1:
The patent employs periodic action by performing resistance measurements at multiple discrete frequency points in a systematic sequence. Rather than continuous measurement, the system periodically switches between different test frequencies (f1, f2, etc.), takes measurements at each frequency, and processes the collected data. This periodic multi-frequency approach efficiently captures the frequency-dependent error characteristics while maintaining a structured measurement process that minimizes unnecessary delays.
Data Source
AI summary
The disclosure describes tissue resistance measurement techniques. To avoid errors caused by bandwidth limitations of the amplifier that amplifies a signal used to determine the tissue resistance, the disclosure describes determining values at different frequencies, where the values include respective error values. The respective error values are proportional to the respective frequencies, and based on this relationship the error value can be removed from the tissue resistance measurement.