Seizure localization by chronic ambulatory electrocorticography.

Aims: To present two patients with medically-refractory focal epilepsy who, following non-diagnostic intracranial monitoring studies, had seizures localized by chronic ambulatory electrocorticography with an implanted neurostimulation device.

Methods: Case reports with clinical details and electrocorticograms showing seizures.

Results: Using electrodes placed at the suspected seizure onset zones, the neurostimulator recorded seizures in both patients at long intervals following implantation (49 days and 7.5 months).

Conclusions: Chronic ambulatory electrocorticography can provide valuable diagnostic information when there is a narrow hypothesis about seizure localization, though there are important caveats related to limited spatial sampling.