Sub-perception Neural Modulation Using Short Pulse Widths
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Solution Overview
Problem
Conventional spinal cord stimulation systems often induce paresthesia, which can be uncomfortable for patients, as they activate large sensory dorsal column nerve fibers, and there is a need for a therapy that can effectively treat pain without causing these sensations.
Innovation Solution
The development of a system that includes electrodes and a neural modulator configured to deliver sub-perception neural modulation, using a feedback system and control system to calibrate and generate a modulation field with an intensity below the patient-perception threshold, selectively stimulating dorsal horn or dorsal root tissue over dorsal column tissue at frequencies less than 1,200 Hz, and employing techniques like fractionalization of current to minimize activation of dorsal column fibers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional spinal cord stimulation is used to treat pain, then pain relief is achieved, but paresthesia is induced which causes discomfort
Solution Approach 1:
The patent changes the stimulation parameters by using shorter pulse widths (e.g., 60-200 microseconds) and specific amplitude levels to selectively activate small sensory fibers while avoiding large sensory fibers that cause paresthesia. This parameter optimization allows pain relief without the uncomfortable sensations associated with conventional stimulation.
Solution Approach 2:
The patent delivers stimulation with localized spatial distribution targeting specific neural structures (dorsal horn or dorsal root tissue) while avoiding activation of dorsal column fibers. By controlling the spatial quality of the modulation field and using fractionalization techniques, the therapy achieves selective neural modulation that provides pain relief without inducing paresthesia.
2Reliability
If stimulation intensity is increased to improve pain relief, then therapeutic effectiveness increases, but patient perception of stimulation increases causing discomfort
Solution Approach 1:
The patent optimizes the balance between amplitude and pulse width parameters to deliver effective therapeutic stimulation below the patient perception threshold. By using shorter pulse widths with appropriately calibrated amplitudes, the system achieves sub-perception neural modulation that provides pain relief without causing uncomfortable sensations.
Solution Approach 2:
The patent employs a feedback system with sensors to detect patient response and adjust stimulation parameters in real-time. This closed-loop control ensures that stimulation remains effective for pain relief while staying below the perception threshold, automatically adapting to maintain therapeutic effectiveness without causing discomfort.
3Measurement precision
If calibration process uses multiple pulse widths to derive sub-perception data, then sub-perception modulation accuracy improves, but calibration time and complexity increase
Solution Approach 1:
The patent performs preliminary calibration by delivering test pulses at multiple different pulse widths to map the strength-duration curve and identify sub-perception parameters before actual therapy delivery. This preliminary characterization of the patient's neural response enables accurate sub-perception modulation while reducing the need for extensive calibration during treatment.
Solution Approach 2:
The patent implements a dynamic calibration process that adapts the number and characteristics of test pulses based on initial patient responses. The system adjusts the calibration protocol in real-time, using feedback from early measurements to optimize subsequent test parameters, thereby reducing overall calibration time while maintaining measurement precision.
Data Source
AI summary
A system example may include electrodes operationally positioned for use in delivering sub-perception neural modulation, a neural modulator configured to use at least some electrodes to generate a modulation field, and a feedback system configured to receive a feedback signal that a generated modulation field provides a perceived or measurable response. A control system may implement a calibration process including controlling the neural modulator to generate the modulation field using a first and second stimulus pulse with a first and second pulse width, respectively, and using the feedback system to determine a first and second reference point that represents an intensity of the modulation field generated using the first and second pulse widths, respectively, that provides the response, and deriving sub-perception calibration data specific to sub-perception modulation delivered using a sub-perception pulse with a sub-perception pulse width.