Neurostimulation Waveform Pre-Pulse Selectivity
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Solution Overview
Problem
Current Deep Brain Stimulation (DBS) systems face limitations in selectively targeting neural elements due to the amplitude-limited nature of stimulation waveforms, which restricts the strength and depth of the electric field, thereby limiting the population of neural elements that can be impacted, and results in diminished selectivity between recruiting nerve cells and fibers.
Innovation Solution
The introduction of waveforms with pre-pulse or post-pulse phases that gradually change amplitude from below to above the initial recruitment threshold, allowing for extended spatial influence without recruiting non-target neural elements, and the use of graphical user interfaces to program implantable pulse generators with customizable waveform parameters to selectively modulate different ratios of neural targets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the amplitude of stimulation waveform is increased to expand spatial influence and recruit more neural elements, then the population of neural elements impacted is improved, but the selectivity between recruiting nerve cells and fibers deteriorates
Solution Approach 1:
The stimulation waveform is segmented into multiple phases: a pre-pulse phase at lower amplitude to selectively recruit target neural elements, followed by a main stimulation phase at higher amplitude. This temporal segmentation allows different phases to target different neural populations, resolving the contradiction between expanding spatial influence and maintaining selectivity.
Solution Approach 2:
A pre-pulse phase is applied before the main stimulation pulse. This preliminary action at lower amplitude selectively activates target neural elements (e.g., nerve cells) before the higher amplitude main pulse, ensuring that the subsequent stimulation builds upon already-recruited elements rather than indiscriminately activating all elements in the field.
2Manufacturing precision
If the amplitude of stimulation waveform is limited to maintain selectivity, then the selectivity between neural elements is improved, but the spatial influence and depth of electric field deteriorate
Solution Approach 1:
The stimulation waveform dynamically adjusts amplitude over time within a single stimulation cycle. The pre-pulse phase uses lower amplitude for selective recruitment, while the main stimulation phase increases amplitude to expand spatial influence. This dynamic amplitude modulation allows the system to achieve both selectivity and spatial coverage that would be impossible with a fixed amplitude waveform.
Solution Approach 2:
The stimulation is delivered as periodic pulses with distinct phases. Each pulse cycle includes a pre-pulse phase followed by a main stimulation phase, creating a periodic pattern that repeatedly applies selective then expansive stimulation. This periodic structure allows the electric field to alternately focus on selectivity and spatial influence, achieving both goals over time.
3Device complexity
If standard amplitude-limited waveforms are used, then device simplicity is maintained, but the ability to selectively modulate different ratios of neural targets deteriorates
Solution Approach 1:
The waveform parameters (amplitude, duration, timing) are changed within different phases of the stimulation cycle. The pre-pulse phase uses specific amplitude and duration parameters optimized for selective recruitment, while the main pulse uses different parameters for broader stimulation. This parameter variation across phases enables selective modulation of neural target ratios without requiring multiple separate devices or complex external programming.
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
This approach enables more precise targeting of neural elements, enhancing the selectivity and effectiveness of DBS by tailoring waveforms to preferentially stimulate either nerve cells or fibers, thereby improving the treatment outcomes for conditions like Parkinson's disease while minimizing side effects.
Implementation Method 1
the amplitude of the pulses, the frequency and duration of the pulses, as well as the electrodes selected to provide such stimulation
Implementation Method 2
one or more of the electrodes to issue a stimulation waveform at the one or more electrodes
Data Source
Figure 1~2
Figure 3
Figure 4A~4C
AI summary
Medical device systems, methods, and algorithms are disclosed for providing complex stimulation waveforms. The waveforms may selectively modulate or activate specific neural targets or selected ratios of specific neural targets. Some of the waveforms include pre-pulse phases defined by parameters, the value of which changes during the pre-pulse phase. Also disclosed herein are graphical user interfaces (GUIs) that allow the selection of waveforms configured to selectively modulate or activate specific neural targets or selected ratios of the neural targets. Adjustable parameters of the waveforms are adjusted automatically based on selection of user-defined parameters.