Comprehensive Literature Review on EEG Findings in Focal Epilepsies: Methodology and Selection Criteria

A comprehensive literature review was conducted to investigate electroencephalographic (EEG) findings in focal epilepsies. Two independent researchers performed a search on January 20th to May 30th, 2020, using the following Pubmed and Medline descriptors, both individually and in various combinations: 'focal', 'partial', 'epilepsy', 'electroencephalographic findings', 'EEG'. Additional filters were applied, including 'review', 'original articles', and language restricted to Spanish and English. All ages were considered.

This search yielded a total of 1223 articles. However, 1063 articles did not provide EEG descriptive findings in focal epilepsies and were subsequently eliminated. Only 160 articles contained data related to EEG. Eleven manuscripts were written in languages other than English and Spanish and were excluded from the review.

After a meticulous review of the remaining 149 papers' methodology, only articles meeting specific criteria were included. These criteria included studies with more than 10 subjects, including a series of cases, previous reviews on different focal epileptic syndromes, ILAE task force positions regarding essential concepts, and papers that provided a detailed description of electrode positions, montage, activation maneuvers, videorecording, and/or electromyography electrodes in their methods section. A total of 69 articles fulfilled these criteria.

Both researchers thoroughly read and analyzed the selected articles. Any discrepancies in selection were resolved through consensus.