Refining Detection of Subclinical Epileptiform Activity in Alzheimer's Disease: A Case-Control Study and Call for a...

Sleep-predominant network hyperexcitability is increasingly recognized as a potential disease-accelerating comorbidity in Alzheimer's disease (AD). However, its prevalence and risk-factors remain debated, largely due to cohort-specific and methodological differences across studies. In this prospective case-control study, we investigated potential ways of improving detection, from translational approaches focusing on rapid eye movement (REM)-sleep to refined electroencephalogram (EEG) setups and added clinical questionnaires.

We recruited 30 patients with early-stage AD without a history of epilepsy and 30 age-matched controls. Participants underwent overnight polysomnography with video-EEG. Interictal epileptic discharges (IEDs) were identified through a structured 3-step review by multiple independent experts using recommended criteria. Neuroanatomic patterns and sleep-related abnormalities were investigated as potential risk factors. Clinical symptoms in favor of epileptic seizures were evaluated through a tailored questionnaire at follow-up.

IEDs were detected in 3 patients (10%) and 1 control (3.33%), a difference not reaching statistical significance (p = 0.612). Most events occurred during non-REM (NREM) sleep. Eight patients (26.67%) reported symptoms compatible with epileptic seizures-one of whom also presented with IEDs. Patients with IEDs or reported symptoms suggestive of potential seizures exhibited more severe sleep-disordered breathing and reduced precuneus volume compared with those without.

Despite efforts to optimize detection accuracy, our findings reveal a lower-than-expected percentage of patients with AD with IEDs, yet support previous findings suggesting that sleep-disordered breathing and specific atrophy patterns could flag at-risk patients, guiding screening in clinical settings. Our findings also favor validation efforts of questionnaires to support the diagnostic process. Finally, we highlight methodological issues in IED detection and call for the re-evaluation and standardization of diagnostic methods and criteria in this population to improve patient care. ANN NEUROL 2026;99:1046-1058.