Flexible, high-resolution cortical arrays with large coverage capture microscale high-frequency oscillations in patients with epilepsy
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7 2023
Source: Epilepsia. 64(7):1910-1924
Details:
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Alternative Title:Epilepsia
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Personal Author:
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Description:Summary
Objective:
Effective surgical treatment of drug resistant epilepsy depends on accurate localization of the epileptogenic zone (EZ). High frequency oscillations (HFOs) are potential biomarkers of the EZ. Previous research has shown that HFOs often occur within submillimeter areas of brain tissue and that the coarse spatial sampling of clinical intracranial electrode arrays may limit the accurate capture of HFO activity. In this study, we sought to characterize microscale HFO activity captured on thin, flexible micro-electrocorticographic (μECoG) arrays, which provide high spatial resolution over large cortical surface areas.
Methods:
We used novel liquid crystal polymer thin-film (LCP-TF) μECoG arrays (0.76–1.72 mm inter-contact spacing) to capture HFOs in eight intraoperative recordings from seven patients with epilepsy. We identified ripple (80 – 250 Hz) and fast ripple (250 – 600 Hz) HFOs using a common energy thresholding detection algorithm along with two stages of artifact rejection. We visualized microscale subregions of HFO activity using spatial maps of HFO rate, signal-to-noise ratio, and mean peak frequency. We quantified the spatial extent of HFO events by measuring covariance between detected HFOs and surrounding activity. We also compared HFO detection rates on microcontacts to simulated macrocontacts by spatially averaging data.
Results:
We found visually delineable subregions of elevated HFO activity within each μECoG recording. 47% of HFOs occurred on single 200 μm diameter recording contacts with minimal high frequency activity on surrounding contacts. Other HFO events occurred across multiple contacts simultaneously, with covarying activity most often limited to a 0.95 mm radius. Through spatial averaging, we estimated that macrocontacts with 2–3 mm diameter would only capture 44% of the HFOs detected in our μECoG recordings.
Significance:
These results demonstrate that thin-film microcontact surface arrays with both high resolution and large coverage accurately capture microscale HFO activity and may improve the utility of HFOs to localize the EZ for treatment of drug resistant epilepsy.
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Source:
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Pubmed ID:37150937
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Pubmed Central ID:PMC10524535
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Document Type:
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Supporting Files:No Additional Files
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