Ictal semiology in supplementary motor area and pre-supplementary motor area epilepsy: A systematic review and meta-analysis.

We conducted a systematic review and meta-analysis of the ictal semiology associated with supplementary motor area (SMA) and pre-supplementary motor area (pre-SMA) epilepsy, to summarize current knowledge of related anatomo-clinical correlations in the context of presurgical evaluation. We conducted the review and reported its results according to the Preferred Reporting Items for Systematic Review and Meta-Analysis statement (PRISMA). We searched PubMed and Embase using relevant keywords related to the SMA and pre-SMA localization, seizure semiology, and scalp electroencephalography (EEG) or stereo-EEG. The risk of bias was evaluated using the QUADAS2 score. Twenty articles were included, with extractable data from 37 patients. We analyzed the included studies and extracted data on the presence of 12 different symptoms. We then performed a meta-analysis of the proportion of patients with each symptom. The most frequently reported ictal feature in SMA epilepsy was asymmetric tonic posturing, observed in 47% of cases. Automatisms (25%) and versive seizures (23%) were also common, while loss of consciousness occurred in 19% of patients. Sensory phenomena (11%) and speech arrest/inhibition (10%) were less frequent. Other features, including symmetric tonic posturing, elementary motor signs, hyperkinetic patterns, affective phenomena, grimacing, and negative motor phenomena, were rarely observed. Little evidence is available on the distinct involvement of the pre-SMA. Although asymmetric tonic posturing appears to be the most common feature of SMA epilepsy, it occurs in fewer than 50% of patients and the level of evidence of this association remains low. The same semiological feature may result from the rapid propagation to adjacent or connected regions; hence, semiology should always be interpreted in the context of a multimodal evaluation. Stereo-EEG investigation remains crucial when EEG and imaging are inconclusive or conflicting.