PREDICTORS OF 5-YEAR REMISSION IN FOCAL EPILEPSY OF UNKNOWN CAUSE

Purpose: To study prognosis and prognostic predictors in patients with FEUC. Method: Two thousand eighty-three patients with FEUC were consecutively seen from 1987 to 2010 in two Epilepsy Centers (Reggio Calabria and Catanzaro, Italy). Nine hundred nine were excluded because of insufficient data, psychogenic seizures, absence of neuroimaging or presence of brain lesions on MRI. The following variables were considered: age, gender, age at onset, family history of epilepsy or febrile seizures (FS), perinatal factors, history of FS, history of status epilepticus, type of seizures, presumed lobar localization, EEG, type of recruitment (incident or prevalent case). Survival curves were generated with Kaplan–Meier method and compared with log-rank test. The end point was cumulative time-dependent chance of 5-year remission. Independent predictors of remission were tested by multivariate analysis (Cox proportional hazards function models). Results: One thousand one hundred seventy-four patients were followed for 1019.4 person-years. One hundred five cases presented 5-yr remission. The cumulative probability of remission was 9% at 5 years, and 14, 18, and 21% at 10, 20, and 30 years. At univariate analysis, factors predicting remission included female gender, older age at onset, family history of epilepsy, drop attacks, and presumed lobar localization. Independent predictors of remission were older age at onset (Hazard Ratio, HR for each increasing year 1.001; 95% confidence interval, CI 1.000–1.002), family history of epilepsy (HR 1.6; 95% 1.1- 2.4), seizures with loss of consciousness (HR 1.7; 95% CI 1.1–2.6), secondarily generalized seizures (HR 1.6; 95% CI 1.0–2.5), drop-attacks (HR 0.2; 95% CI 0.0–0.8), parietal epilepsy (HR 3.2; 95% CI 1.4–7.1), occipital epilepsy (HR 1.8; 95% CI 1.1–3.2), and being an incident case (HR 2.9; 95% CI 1.84.6). In incident cases, independent prognostic predictors were loss of consciousness and occipital epilepsy. Conclusion: One-fifth of cases with FEUC attain 5-yr remission during follow-up. Older age at onset, family history of epilepsy, seizure type, and lobar localization are independent prognostic predictors. However, only lobar localization and seizures with loss of consciousness are favorable prognostic predictors in incident cases.