High-Charge Electrode Contacts for Non-Damaging Neural Block
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Solution Overview
Problem
Existing methods for neural conduction block, such as High Frequency Alternating Current (HFAC) and Direct Current (DC), face challenges in achieving a reversible block without causing onset responses or nerve damage, respectively.
Innovation Solution
The use of therapy delivery devices with electrode contacts made of high-charge capacity materials, applying multi-phase DC currents with cathodic and anodic phases to block neural signal transmission while balancing net charge, optionally combined with HFAC to reduce onset responses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If HFAC is applied to achieve a localized reversible conduction block, then the block is immediate and complete, but an onset response occurs that can last many seconds and cause painful sensations and muscle contractions
Solution Approach 1:
A DC pre-pulse is applied before the HFAC stimulus to depolarize the neural membrane in advance. This preliminary action raises the threshold potential, preventing action potentials from occurring during the HFAC onset phase, thereby eliminating the painful onset response while maintaining the immediate and complete conduction block benefit
Solution Approach 2:
The patent changes the electrical parameters by applying a DC component with specific amplitude and duration before the HFAC stimulus. By carefully controlling the DC pre-pulse parameters (amplitude, duration, timing), the neural membrane potential is shifted to a state where subsequent HFAC stimulation produces block without activation, resolving the contradiction between speed and harmful effects
2Object-generated harmful factors
If DC is applied with slowly ramped amplitude to avoid onset response, then no painful sensation occurs, but nerve damage results due to free radical creation at the electrode interface
Solution Approach 1:
The patent merges DC and HFAC into a combined waveform where a brief DC pre-pulse is followed by HFAC stimulation. This combination allows the DC component to prevent onset responses without requiring prolonged DC application, thereby avoiding the nerve damage associated with extended DC exposure while maintaining the benefit of painless activation
Solution Approach 2:
The patent uses periodic HFAC stimulation following the DC pre-pulse. The periodic nature of HFAC allows for intermittent neural block without continuous DC exposure, reducing cumulative charge delivery and minimizing the risk of electrode interface damage and free radical formation while maintaining effective neural control
3Duration of action of moving object
If large HFAC amplitudes and higher frequencies are used to shorten the onset response, then the block duration is reduced, but the initial portion lasting one to two seconds cannot be eliminated
Solution Approach 1:
The DC pre-pulse is applied immediately before the HFAC stimulus, creating a preliminary depolarization state that persists through the critical one to two second onset period. This timing ensures that when HFAC is applied, the neural membrane is already in a refractory state, preventing the harmful initial portion of the onset response regardless of HFAC amplitude or frequency parameters
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
Achieves a safe, reversible neural conduction block without nerve damage, allowing prolonged application of DC currents and minimizing onset responses through charge balancing.
Implementation Method 1
A localized, reversible, electrical nerve conduction block would be an attractive way of addressing these conditions
Implementation Method 2
High Frequency Alternating Current (HFAC) waveforms have been shown to provide a very localized, immediate, complete, and reversible conduction block for motor and sensory nerve fibers
Data Source
AI summary
Devices and methods for blocking signal transmission through neural tissue. One step of a method includes placing a therapy delivery device into electrical communication with the neural tissue. The therapy delivery device includes an electrode contact having a high charge capacity material. A multi-phase direct current (DC) can be applied to the neural tissue without damaging the neural tissue. The multi-phase DC includes a cathodic DC phase and anodic DC phase that collectively produce a neural block and reduce the charge delivered by the therapy delivery device. The DC delivery can be combined with high frequency alternating current (HFAC) block to produce a system that provides effective, safe, long term block without inducing an onset response.