DBS Waveform Emulator Synchronizes fMRI with Stimulation Cycles
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Solution Overview
Problem
Current deep brain stimulation (DBS) treatments lack real-time feedback mechanisms to optimize stimulation parameters, and functional magnetic resonance imaging (fMRI) is not easily achievable in patients with implanted DBS pulse generators due to communication time lags and FDA restrictions, leading to inaccuracies in assessing DBS excitation states during fMRI scans.
Innovation Solution
A system and method that detect bioelectrical signals from DBS and generate timing pulses to synchronize image data acquisition with the DBS excitation cycle, using a DBS waveform emulator to transform bioelectrical signals into digital logic pulses and predict future active periods, allowing for accurate binning of medical images corresponding to DBS ON and OFF conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fMRI is performed on patients with implanted DBS pulse generators, then real-time feedback on brain response to DBS can be obtained, but communication time lags between programming and actual stimulation cause large errors in assessing stimulation state
Solution Approach 1:
The system pre-determines the stimulation state (ON or OFF) before fMRI data acquisition begins, using the known timing of DBS parameter changes. This allows the system to account for communication delays and accurately associate each fMRI volume with the correct stimulation state, eliminating errors from time lags between programming and actual stimulation.
Solution Approach 2:
The system implements a feedback mechanism that tracks the actual stimulation state throughout the fMRI scan by monitoring when parameter changes are communicated to the pulse generator. This feedback loop allows accurate binning of fMRI data according to the true stimulation state, resolving the timing discrepancy between programming and delivery.
2Ease of operation
If DBS parameters are programmed outside the MRI scanner, then programming can be completed before scanning, but a multi-second time lag occurs during communication from controller to pulse generator to electrodes
Solution Approach 1:
The system determines the stimulation state in advance, before fMRI acquisition begins, by tracking when parameter changes are communicated to the pulse generator. This preliminary determination of stimulation states allows accurate association of each acquired image volume with the correct ON or OFF condition, compensating for the communication time lag.
3Measurement precision
If long time interval exists between pulse generator programming and fMRI onset, then setup time is sufficient, but large errors occur in assessing stimulation state leading to significant drops in fMRI sensitivity
Solution Approach 1:
The system pre-determines stimulation states before fMRI acquisition by tracking communication timing between the controller and pulse generator. This preliminary establishment of the stimulation state timeline allows accurate binning of fMRI data even after long intervals, preventing sensitivity drops that would occur from timing errors.
Data Source
AI summary
A system and method for analyzing bioelectrical signals generated during a deep brain stimulation (DBS) includes an apparatus having a housing having a signal input and a signal output and an electrical circuit disposed within the housing and electrically coupled between the signal input and the signal output. The electrical circuit is configured to receive bioelectrical signals corresponding to a cyclic excitation signal transmitted by a pulse generator during a DBS and generate an output signal comprising a series of timing pulses, wherein each timing pulse simulates an envelope of the cyclic excitation signal. The signal output of the housing is electrically coupleable to an auxiliary trigger input of an imaging system and the series of timing pulses can be used to trigger image data acquisition.