Examining How Impedance Mismatches Impact Local Field Potential Recordings for Deep Brain Stimulation
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Deep brain stimulation (DBS) is a surgical procedure in which electrodes are inserted in the brain to mitigate the symptoms of different neurological disorders. In recent years, there has been a keen interest on the emergence of bi-directional DBS (bdDBS) devices. Unlike normal DBS, bdDBS is also able to record local field potentials (LFP) while stimulating the brain. Clinicians can use the recorded LFP data to optimize the stimulation parameters to effectively mitigate symptoms. BdDBS devices typically record LFPs using a differential recording setup. Such a setup is advantageous for it ability to reduce noise from distal sources. However, given today’s engineering constraints, it also has the potential to distort the recording. Impedance mismatches between the contacts used to record LFPs can amplify the signal. Combined with front end amplification circuitry, impedance mismatching can result in gain compression which would introduce misleading information into the LFP recording. This project will model the relationship between impedance mismatches and gain compression. It will also examine how gain compression may impact LFP recordings and provide methods to compensate for them.