Neural Stimulation Device ECAP Feedback Control
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Solution Overview
Problem
Existing spinal cord electrical stimulation (SCS) systems require multiple comparisons to adjust stimulation pulse amplitude, leading to prolonged patient discomfort and inefficient power consumption, as they struggle to timely and accurately adjust the pulse to an appropriate state.
Innovation Solution
A neural stimulation device comprising a pulse generator, an evoked compound action potential (ECAP) sensor, and a neural stimulation controller that senses the ECAP after each pulse generation cycle and adjusts the amplitude of subsequent pulses to ensure the peak-to-peak value falls within a comfort range, allowing for immediate and accurate adjustment in two steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple comparisons of ECAP value and target value are performed to adjust pulse amplitude, then the stimulation pulse can approach the target value continuously, but the adjustment time is prolonged and patient discomfort increases
Solution Approach 1:
The patent pre-calculates and stores the correspondence relationship between ECAP values and pulse amplitudes before actual stimulation. When adjustment is needed, the controller directly queries the pre-established mapping table to obtain the target pulse amplitude, eliminating the need for multiple iterative comparisons during real-time operation. This preliminary preparation significantly reduces adjustment time while maintaining precision.
2Measurement precision
If multiple comparisons are performed to adjust pulse amplitude, then the target ECAP intensity can be approached continuously, but power consumption increases
Solution Approach 1:
The mapping table between ECAP values and pulse amplitudes is pre-calculated and stored in memory during device initialization or calibration phase. During actual stimulation, the controller performs a simple table lookup operation rather than conducting multiple iterative measurements and adjustments, dramatically reducing computational load and power consumption while achieving the same adjustment precision.
3Reliability
If the stimulation pulse amplitude is adjusted through multiple comparisons, then the ECAP intensity can be maintained constant, but the adjustment efficiency is low
Solution Approach 1:
The system continuously monitors ECAP values during stimulation and uses the pre-established mapping table to determine the appropriate pulse amplitude adjustment. The controller compares the measured ECAP value with the target value, queries the mapping table for the corresponding optimal pulse amplitude, and adjusts the stimulation accordingly. This feedback mechanism maintains constant ECAP intensity while improving adjustment efficiency through the pre-prepared lookup table.
Data Source
AI summary
A neural stimulation device is disclosed, including: a pulse generator, an evoked compound action potential (ECAP) sensor, and a neural stimulation controller. The neural stimulation controller instructs the ECAP sensor to sense an ECAP after a pulse is generated by the pulse generator within a first pulse generation cycle, adjust an amplitude of a pulse generated within a second pulse generation cycle in response to a peak-to-peak value of the ECAP being not in a comfort range, and adjust, according to an expected peak-to-peak value, an amplitude of a pulse generated within a third pulse generation cycle in response to a peak-to-peak value of the ECAP after the pulse is generated within the second pulse generation cycle being still not in the comfort range. The expected peak-to-peak value is in the comfort range including an amplitude dimension of the pulse and a peak-to-peak value dimension of the ECAP.