Wireless high-density electroencephalography in the perioperative setting

Electroencephalographic (EEG) systems used in the operating room are constrained to frontal channels, providing limited neuroanatomical insights into altered perioperative brain states. Our objective is to present pragmatic strategies for placing whole-scalp, high-density EEG systems perioperatively that enable more comprehensive analysis.

We present the successful implementation of wireless high-density (72-channel) EEG in the perioperative setting for the ongoing Caffeine, Postoperative Delirium, and Change in Outcomes after Surgery (CAPACHINOS-2) clinical trial (NCT05574400). Placement time was calculated, impedance and data quality were assessed, and data acquisition and analysis pipelines were established. Lastly, proof-of-principle analyses using source localization were conducted.

High-density wireless EEG data have been successfully acquired for n = 45 participants, with median (interquartile range) placement time of 34 (25 - 52) minutes. Data acquisition was supported by an established workflow, and a subsequent data processing pipeline was used to evaluate channel quality, remove artifacts, and generate proof-of-principle high-density analyses.

Compared to a low-density system used for a similar, previous clinical trial (n = 54 participants), preoperative median impedance values (kΩ) were lower with the high-density system (13 [11-16] vs. 39 [28-47] kΩ; p < 0.001). Additionally, proof-of-principle analysis demonstrates a more complex connectivity matrix and broader distribution of cortical alpha rhythms after induction of general anesthesia with the high-density system, highlighting an expanded capacity for neurophysiologic analysis.

Wireless high-density EEG serves as a feasible, promising tool to advance understanding of altered perioperative brain states by providing high spatiotemporal resolution of cortical oscillations.