Nerve Stimulation Apparatus Using ECAP Peak-to-Peak Ratio Feedback
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Solution Overview
Problem
The existing closed-loop spinal cord electrical stimulation systems rely solely on the peak-to-peak value of evoked compound action potential (ECAP) for feedback, which cannot comprehensively reflect the action potentials caused by nerve fibers of different diameters, leading to suboptimal clinical outcomes.
Innovation Solution
A nerve stimulation apparatus comprising a pulse generator, an ECAP sensor, and a controller that adjusts the amplitude of stimulation pulses based on the peak-to-peak ratio of ECAP, ensuring the ratio falls within a comfort range to effectively manage the excitability of nerve fibers of varying diameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the peak-to-peak value of ECAP is used as the feedback basis for spinal cord electrical stimulation, then the control system can be simplified, but the measurement precision is insufficient to reflect action potentials from nerve fibers of different diameters
Solution Approach 1:
The patent segments the ECAP waveform analysis into multiple components: peak-to-peak value, peak-to-peak ratio, and area under the curve. Each parameter provides different information about nerve fiber activation, allowing the system to comprehensively assess stimulation effects on nerve fibers of different diameters while maintaining a relatively simple control architecture.
Solution Approach 2:
The patent transitions from using a single-dimensional metric (peak-to-peak value) to multi-dimensional metrics by introducing the peak-to-peak ratio (comparing positive and negative peaks) and area under the curve. This dimensional expansion enables more precise characterization of ECAP waveforms and nerve fiber activation states.
2Ease of operation
If only the peak-to-peak value of ECAP is monitored, then the feedback control is simpler to implement, but the clinical efficacy is suboptimal due to inability to reflect stress on nerve fibers of different diameters
Solution Approach 1:
The feedback control mechanism is segmented into multiple assessment dimensions: peak-to-peak value for overall activation level, peak-to-peak ratio for differential fiber activation patterns, and area under the curve for total neural response. This segmentation enables comprehensive clinical assessment while maintaining automated control.
Solution Approach 2:
The patent implements a closed-loop feedback system that continuously monitors ECAP parameters (peak-to-peak value, peak-to-peak ratio, area under the curve) and adjusts stimulation parameters accordingly. This feedback mechanism ensures optimal clinical efficacy by adapting stimulation to the patient's real-time neural response while maintaining automated operation.
3Reliability
If the amplitude of stimulation pulses is adjusted to increase ECAP amplitude for stronger patient perception, then the stimulation effectiveness is improved, but the patient comfort may deteriorate due to excessive stimulation sensation
Solution Approach 1:
The patent employs closed-loop feedback control that continuously monitors ECAP parameters (peak-to-peak value, peak-to-peak ratio, area under the curve) and adjusts stimulation amplitude accordingly. This feedback mechanism maintains stimulation effectiveness by adapting to the patient's neural response while preventing excessive amplitude that would cause discomfort.
Solution Approach 2:
The system dynamically changes stimulation parameters (amplitude, pulse width, frequency) based on real-time ECAP measurements. By adjusting multiple parameters simultaneously rather than solely increasing amplitude, the system achieves effective stimulation while maintaining patient comfort through optimized parameter combinations.
Data Source
AI summary
Disclosed are a nerve stimulation apparatus and system, and a control method. The apparatus comprises: a pulse generator, an evoked compound action potential (ECAP) sensor, and a controller. The pulse generator is used for generate a pulse according to an instruction of the controller; the ECAP sensor is used for sensing an evoked compound action potential according to an instruction of the controller; and the controller is used for instructing, after a pulse is generated within a current pulse generation cycle, the ECAP sensor to sense an evoked compound action potential, acquiring a peak-to-peak ratio of the evoked compound action potential, and when the peak-to-peak ratio is not within a comfort range, adjusting the amplitude of a pulse to be generated within a subsequent pulse generation cycle iteratively until the peak-to-peak ratio is within the comfort range.