Factors associated with epileptiform discharges in patients visiting a memory clinic: A retrospective study

Epilepsy is a common comorbidity in older adults, particularly those with neurodegenerative diseases such as Alzheimer's disease. However, recognizing epilepsy in patients with dementia can be challenging, as its symptoms often mimic cognitive fluctuations. Reliable clinical indicators validated by electroencephalography (EEG) are needed for timely diagnosis and management. This study investigated predictors of epileptiform discharges in patients visiting a memory clinic, focusing on the diagnostic role of EEG. We retrospectively screened 159 patients who underwent medical interviews with physicians and EEG testing between April 2022 and March 2023. Data from dementia-related questionnaires, comprehensive geriatric assessments, EEG, magnetic resonance imaging, and single-photon emission computed tomography were evaluated. Among the 156 patients with dementia (after excluding 3 with epilepsy), 77 exhibited epileptiform discharges, predominantly left temporal (87%) or bilateral (13%), and female patients were more often affected (p < 0.05). Logistic regression analysis revealed that discharges were associated with variable cognitive decline. Approximately two-thirds of patients with epileptiform discharges answered "yes" to the interview item assessing "cognitive decline with variability," highlighting the predictive value of this symptom. However, the remaining cases required EEG testing for detection. Our findings underscore the importance of recognizing epilepsy during dementia screening. While clinical interviews provide valuable insights, EEG remains indispensable for accurate diagnosis and treatment.