Distinct epileptiform abnormalities are associated with clinical seizures in Alzheimer’s disease

Objective: Examine the relationship between scalp EEG biomarkers of hyperexcitability in Alzheimer’s disease (AD) and determine how these electrical biomarkers relate to the clinical expression of seizures in AD. Methods: In this cross-sectional study, we performed 24-hour ambulatory scalp EEGs on 43 cognitively normal elderly healthy controls (HC), 41 early-stage AD participants with no history or risk factors for epilepsy (AD-NoEp), and 15 early-stage AD participants with late-onset epilepsy related to AD (AD-Ep). Two epileptologists, blinded to diagnosis, visually reviewed all EEGs and annotated all potential epileptiform abnormalities. A panel of 9 epileptologists, blinded to diagnosis, was then surveyed to generate a consensus interpretation of epileptiform abnormalities in each EEG. Results: Epileptiform abnormalities were seen in 53% of AD-Ep, 22% of AD-NoEp, and 4.7% of HC participants. Specific features of epileptiform discharges, including high frequency, robust morphology, ri...