Investigation of Paediatric Occipital Epilepsy Using Stereo-Eeg Reveals a Better Surgical Outcome Than in Adults, Especially when the Supracalcarine Area is Affected.

Occipital epilepsy is the least common among surgical series because: (1) the location makes it hard to asses by EEG; (2) the seizure semiology often reflects propagation; and (3) surgery entails a high risk of neurological deficits. In children, subjective symptoms are harder to assess, adding to the difficulty of a proper diagnosis. We aimed to determine electroclinical characteristics of occipital lobe epilepsy in a paediatric population by reviewing 20 children between one and 16 years, who had undergone intracranial recordings with depth electrodes. Eight patients had pure occipital epilepsies and 12 had "occipital plus" epilepsies. We identified four different seizure spreading patterns: (1) pure occipital (40%) with oculomotor symptoms; (2) temporal (30%) with hypomotor behaviour and automatisms; (3) frontal (20%) with movements of the limbs; and (4) spasms (10%). Two thirds of the children above 11 years reported visual aura, but this was probably underestimated in younger children as some seizures began with non-specific motion arrest. Automatisms were only observed when the lateral temporal lobe was involved. Patients with a pure occipital form had a seizure onset zone strictly in the occipital lobe. Lingual and cuneus gyri were the most epileptogenic structures. Scalp EEG showed diffuse EEG abnormalities in two thirds of the patients and 25% of these led to false lateralization of the SOZ. Although MRI lesions were always visible, imaging and scalp EEG could be misleading and often not sufficient to guide surgery. After surgery, 68% of the patients were classified as Engel Class I, and surgical outcome was even better for patients in whom the supracalcarine area was affected, with 87.5% reaching seizure freedom. Seizure spread patterns in occipital epilepsy are similar in paediatric and adult populations, even though it is often impossible to obtain subjective symptoms in children. Postsurgical outcome is better than in adults, especially in patients in whom the supracalcarine area is affected.