Dynamic Evolution of Quantitative Electroencephalography During Graded Intracranial Hypertension and Screening of Candidate Early-Warning Features in a Rabbit Model

Background and Objectives: Elevated intracranial pressure (ICP) is common to many encephalopathies, but the evolution of quantitative electroencephalography (qEEG) indices along a pressure gradient—and their relative suitability for early warning—have not been systematically compared. In this exploratory study we established a stepwise, steady-state rabbit model of graded intracranial hypertension and screened candidate early-warning features against prespecified criteria. Materials and Methods: Eight male New Zealand rabbits were studied; two were excluded—one for circulatory failure during catheterization and one for refractory status epilepticus that reached a humane endpoint—leaving six that completed the protocol. Repeated small-volume inflation of a left parenchymal water balloon was used to define five windows: baseline (BL; ICP < 10 mmHg), 15–20, 25–30 and 35–40 mmHg, and an end stage (END). Eight-channel EEG was recorded synchronously, and δ, θ, α and β power, together with the amplitude-integrated EEG (aEEG) upper margin, lower margin and bandwidth, were computed. Seven candidate features and three criteria (evolution timing, individual consistency and strength of association with ICP) were fixed before analysis; selection stability was assessed by leave-one-rabbit-out (LORO) cross-validation.