[Combined epilepsy with generalized and focal seizures]

Combined epilepsy (with generalized and focal seizures) is a recently accepted and yet underreported epilepsy type. We intended to review the literature of combined epilepsy and to report the individual findings of the 31 combined epilepsy patients in our database. Thereafter, we investigated the characteristics of the patients at the group level.

The individual findings of the 31 patients were tabulated. We characterized the group with special reference to epidemiology, timing and the sequence of generalized and focal seizures, family history of seizures and severity of the electro-clinical phenotype. The variables were compared to those of the generalized epilepsy and the focal epilepsy groups of our database. We carried out statistical analyses by the two-sided Fishers's exact test and the Kruskal-Wallis and post-hoc Dunn tests.

The prevalence of combined epilepsy was 1.56% within the total sample of the classifiable epilepsy patients. Females were affected more often than males (67.7% and 32.3%, respectively). Statistically significant associations emerged firstly between the "short interval" subgroup (where the generalized and focal seizures occurred with short time difference) and the lack of other cerebral abnormality, and secondly between the "long interval" subgroup (where 4 to 37 years elapsed between the occurrence of the two seizure types) and the presence of other brain abnormality (p = 0.02). The proportion of patients with positive family history of seizures was greater in the combined epilepsy- than in the generalized epilepsy group (p = 0.03) and the focal epilepsy group (p < 0.0001) of the database. The electro-clinical phenotype of the absence seizures showed more atypical findings (indicating poor prognosis) in combined epilepsy than in the generalized absence epilepsy patients of the database (p < 0,0001). Despite dissimilar patient selection and study design, our main findings were in accord with those of prior studies. The dissection of the combined epilepsy group into the "long interval" and "short interval" subgroups was a novel approach that highlighted the dissimilar pathogenetic and clinical correlates of each.

The case reports might facilitate the spread of information about combined epilepsy in the medical community. Analyses of the patients at the group level resulted in clinically useful pieces of evidence.