Anatomo-clinical correlations in patients with lateral occipital seizures: A systematic review

Epilepsies presenting with lateral occipital seizures (LOS) pose diagnostic challenges due to their rarity and association with complex visual symptoms. We performed a systematic review to characterize the ictal semiology, electroencephalographic, imaging, and surgical features of LOS.

A comprehensive literature search was conducted between 1990 and March 2024 to identify patient-level studies reporting focal seizures originating from the occipital lobe, confirmed whenever possible by invasive EEG, MRI lesion, and postoperative outcome. Cases with occipital semiology due to propagation from extra-occipital onset zones were excluded.

A total of 105 abstracts were considered resulting in 13 articles reviewed, and 248 patients were analyzed. Visual symptoms were present in 8%-88% of patients: visual hallucinations and illusions, and oculomotor disturbances being the most frequent manifestations. Oculomotor signs, including eye deviation and eyelid myoclonia, were common but non-specific for lateralization. Scalp EEG frequently demonstrated false lateralization, and only a median of 23% of patients underwent invasive monitoring. LOS originating from the lateral occipital cortex exhibited propagation along ventral and dorsal streams, accounting for associated temporal, parietal, and frontal manifestations. MRI lesions were present in 75%-79% of patients, including focal cortical dysplasia, tumors, and cavernomas. Surgical resection yielded Engel class I outcomes in 22%-70% of cases, with pediatric patients demonstrating higher seizure-free rates. Postoperative visual deficits occurred in 17%-80% of patients.

LOS represent a clinically and anatomically distinct form of occipital epilepsy. Their hallmark semiology reflects lateral extrastriate cortical activation and propagation through ventral and dorsal pathways. Accurate localization requires integration of semiology, multimodal imaging, and invasive EEG. Tailored surgical interventions achieve favorable seizure outcomes, particularly in pediatric populations, while careful mapping is essential to preserve visual function. Future studies should refine lateral versus mesial occipital differentiation and optimize surgical planning through advanced imaging and electrophysiology.