EEG features in late-onset epilepsy: possible correlation with cognitive impairment

Area of Science:

• Neurology
• Neurophysiology
• Geriatrics

Background:

• Late-onset epilepsy (LOE) is a significant risk factor for cognitive impairment and dementia.
• The relationship between LOE and cognitive decline is bidirectional and complex.
• Scalp electroencephalography (EEG) is a potential tool for assessing cognitive function in LOE, but its utility is underexplored.

Purpose of the Study:

• To investigate the association between specific EEG patterns and cognitive impairment in individuals with late-onset epilepsy.
• To identify EEG markers that can predict cognitive impairment in LOE.
• To explore potential neurodegenerative origins of LOE with unknown etiology.

Main Methods:

• A cross-sectional study involving patients with LOE (seizure onset ≥55 years) and age-matched healthy controls who underwent 24-h EEG monitoring.
• Standardized neuropsychological metrics were used to diagnose cognitive impairment.
• EEG features were extracted using computer-based methods and analyzed using regression models and the least absolute shrinkage and selection operator (LASSO) model.

Main Results:

• EEG markers of temporal neural hyperexcitability, including temporal intermittent rhythmic delta activity (TIRDA) and anterior temporal epileptiform discharges, were associated with cognitive impairment in LOE.
• Bilateral anterior temporal epileptiform discharges were the strongest predictor of cognitive impairment in LOE of unknown etiology (OR 53.280).
• The LASSO model achieved high discriminative accuracy (AUC 0.869) for cognitive impairment in LOE.

Conclusions:

• Specific EEG patterns, especially those indicating temporal hyperexcitability, are associated with cognitive impairment in late-onset epilepsy.
• LOE of unknown etiology may share neurodegenerative mechanisms with conditions like Alzheimer's disease.
• Further longitudinal research is warranted to elucidate the role of EEG features in the LOE-dementia relationship.