The prognosis for control of seizures with medications in patients with MRI evidence for mesial temporal sclerosis

Purpose: Mesial temporal sclerosis (MTS) is the most common and important pathology in temporal lobe epilepsy (TLE), and its presence in magnetic resonance imaging (MRI) scans is strongly correlated with a successful surgical outcome. Despite the general assumption that patients with MTS respond poorly to medication, the long-term prognosis for such patients has not yet been investigated. We studied the overall clinical prognosis of patients with MTS and analyzed the factors related to the degree of medical responsiveness. Methods: Case patients were actively followed up at the Yonsei Epilepsy Clinic in Seoul, Korea, for >2 years. A structured interview and a thorough clinical evaluation were conducted, MRI scans, at the field strength of 1.0 or 1.5 Tesla, were performed with T-1- and T-2-weighted coronal and axial spin-echo images. All coronal slices were less than or equal to 5-mm thick with no gap. Two neurologists and one radiologist determined the presence of MTS in MRIs by visual analysis. Results: The MTS group consisted of 104 patients. Of these, 26 (25%) were completely controlled with adequate therapy, and 40 (38%) were intractable, despite aggressive anticonvulsant polytherapy. The remaining 37% had their seizure frequencies reduced by greater than or equal to 50%, but were not seizure free. The age of seizure onset was significantly younger in the intractable group than in the well-controlled group. patients with a history of febrile convulsions or with epileptiform discharges in their electroencephalogram (EEO) had poorer seizure control (p < 0.05) than those who did not. Among the 16 patients who had no previous treatment, five (31%) became seizure free, and two were intractable. Conclusions: Not all patients with MTS are medically intractable; 25% of the patients in our study achieved complete control while receiving medication. Poor seizure control was related to an early age of seizure onset, a history of febrile convulsions, and epileptiform discharges on the EEG.