Investigation of lateralized periodic discharge features associated with epileptogenesis

Objective

To identify factors, especially the electrographic features, that predispose patients with lateralized periodic discharges (LPDs) to epilepsy development.

Methods

We included adults, without epilepsy history, who had LPDs on continuous EEG (cEEG) monitoring during hospitalization. We characterized LPDs based on American Clinical Neurophysiology Society rhythmic and periodic pattern modifiers. The outcome variable was epilepsy development as defined by clinical seizure after discharge. We used a Cox regression model to calculate adjusted hazard ratios (aHR) for epilepsy development.

Results

Of 174 patients, 52 (30 %) developed epilepsy during a median follow-up time of 15.0 (IQR 62.1) months. We found that an LPD-plus pattern was associated with an increased risk of epilepsy development during the follow-up period [aHR 2.67 (95 %CI 1.26–5.64)]. We also found that LPD frequency ≥ 1.5 Hz was associated with an increased risk of epilepsy development during the first year of follow-up [aHR 2.27 (95 %CI 1.02–5.05)].

Conclusions

Among patients with LPDs, the presence of a plus pattern and discharge frequency ≥ 1.5 Hz are both independently associated with more than two-times increased risk of epilepsy development.

Significance

Identification of EEG-based predictors of epileptogenesis in patients with LPDs can help early identification of patients at higher risk for future seizures and help tailor their management.