Neurostimulation Pulse Width and Amplitude Adjustment
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Solution Overview
Problem
Current neurostimulation systems face challenges in selectively stimulating specific ranges of nerve fiber diameters across varying stimulation amplitude levels, leading to side effects and limited therapeutic coverage due to the differential activation of larger and smaller nerve fibers.
Innovation Solution
A method and system that adjust pulse amplitude and pulse width values to increase the intensity of electrical stimuli, allowing for selective stimulation of nerve fibers of specific diameters while preventing the activation of smaller Adelta nerve fibers, using an external control device with a user interface and processor to vary these parameters and generate optimized stimulation parameter sets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the stimulation amplitude is increased to activate larger nerve fibers for therapeutic benefit, then the therapeutic effect is improved, but smaller Adelta nerve fibers are also activated causing side effects and pain
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting pulse width in inverse proportion to amplitude increases. When amplitude is increased to activate larger therapeutic nerve fibers, pulse width is simultaneously decreased to prevent activation of smaller Adelta fibers that cause pain. This dual parameter adjustment resolves the contradiction by changing both amplitude and pulse width parameters in a coordinated manner.
2Adaptability or versatility
If the stimulation intensity is increased to expand therapeutic coverage, then more nerve fibers are activated, but the volume of non-target tissue stimulated increases causing unwanted sensations
Solution Approach 1:
The patent applies local quality by creating a non-uniform stimulation profile through coordinated amplitude and pulse width adjustments. Larger nerve fibers (therapeutic target) are activated with higher amplitude and longer pulse width, while smaller Adelta fibers (harmful target) are protected by simultaneously decreasing pulse width when amplitude increases. This creates different effective stimulation conditions for different fiber types within the same tissue volume.
3Device complexity
If fixed electrode combination and pulse width are used to simplify the system, then device complexity is reduced, but selective control over nerve fiber diameter recruitment is limited
Solution Approach 1:
The patent applies dynamics by making the pulse width parameter dynamic rather than fixed. The pulse width automatically adjusts in response to amplitude changes, creating a dynamic stimulation regime that adapts to different therapeutic needs. This dynamic adjustment enables selective control over nerve fiber recruitment without requiring complex additional hardware, resolving the contradiction between simplicity and adaptability.
Data Source
AI summary
A method of stimulating nerve tissue, a tissue stimulation system, and an external control device are provided. The method, system, and control device causes an electrical stimulus to be applied to at least one electrode adjacent the nerve tissue of a patient. The applied electrical stimulus comprises a plurality of pulses defined by a pulse width value and an amplitude value. The pulse amplitude value is increased (e.g., manually), and the pulse width value is automatically decreased in response to increasing the pulse amplitude value in a manner that increases the intensity of the applied electrical stimulus. Alternatively, the pulse width value may be decreased (e.g., manually), and the pulse amplitude value automatically increased in response to decreasing the pulse width value in a manner that increases the intensity of the applied electrical stimulus.