Abstract Details

Title Assessing the Long-term Stability of Chronic Wireless Floating Microelectrodes in the Visual Cortex of Human Participants

Topic Neuro-ophthalmology/Neuro-otology

Presentation(s) P10 - Poster Session 10 (8:00 AM-9:00 AM)

Poster/Presentation
Number 17-015

Objective To develop and apply a reproducible image-based methodology of the positional stability of the wireless floating microelectrode arrays (WFMAs) of the Intracortical Visual Prosthesis (ICVP) implanted in the visual cortex of two human participants with blindness.

Background Quantifying the stability of the implanted electrodes is essential to the long-term viability and safety of the chronically implanted systems. The ICVP uniquely avoids surface and cabled arrays, which are known in the literature to lose positional integrity in the primate brain. Each WFMA contains 16 stimulating electrodes inserted into the parenchyma. Although quantitative evidence of electrode stability in humans is limited, the stability of penetrating WFMAs in canine cortices has demonstrated no histological evidence of migration. Using preoperative MRI and serial, post-operative CT scans, electrode migration can be quantitatively monitored.

Design/Methods Two participants with blindness were implanted with WFMAs in the right dorsolateral occipital cortex: Participant 1 (53-year-old male) received 25 implanted WFMAs; Participant 2 (65-year-old male) received 32 implanted WFMAs. Preprocessing and cortical surface reconstruction were performed using FreeSurfer v.8.1.0. Co-registration of the preoperative MRI and serial CT scans (0 days to 3 years for Participant 1; 0 days to 6 months for Participant 2) was performed using MATLAB 2021b and iELVis repository. Electrode localization and displacement were quantified using 3D Slicer v.5.8.1.

Results Anatomical preoperative MRI scans and postoperative CT scans were obtained for each participant at defined time intervals. Image preprocessing and co-registration using MATLAB 2021b/iELVis repository was implemented in both participants. Electrode localization and longitudinal analysis is in progress to quantify positional stability.

Conclusions This study establishes a reproducible image-based method for evaluating WFMA stability in individuals implanted with the ICVP system. Upon completion of the analysis, this approach will provide quantitative data for the viability and safety of the wireless penetrating arrays for the chronic implantation of the cortical visual prosthesis.

Authors/Disclosures
Katarina Stephan PRESENTER	Miss Stephan has nothing to disclose.
John Collins, MD, PhD	Dr. Collins has received personal compensation in the range of $5,000-$9,999 for serving as an Expert Witness for Various legal firms.
Yiwen Jiang	Mr. Jiang has nothing to disclose.
Carmen Pons, MD, PhD	Dr. Pons has nothing to disclose.
Philip Troyk, PhD	Dr. Troyk has received personal compensation for serving as an employee of Sigenics, Inc. Dr. Troyk has stock in Sigenics, Inc. Dr. Troyk has received personal compensation in the range of $500-$4,999 for serving as a Reviewer with NIH.
Vernon L. Towle, PhD (University of Chicago)	No disclosure on file

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