Clinical features and postsurgical outcomes of medial temporal lobe epilepsy resulting from focal lesions in children with onsets under 3 years of age

Abstract

  Objective: To clarify the clinical characteristics and surgical prognosis of medial temporal lobe epilepsy (mTLE) resulting from focal lesions in infants and young children. Methods: We retrospectively reviewed the medical charts of 18 patients with mTLE and an onset under 3 years of age. All subjects underwent focal resection surgery at the National Center of Neurology and Psychiatry hospital between January 2007 and July 2018 and were followed-up for more than a year after surgery. Results: The 18 patients consisted of 7 males and 11 females. The median age of onset, age at surgery, and follow-up period were 16, 37, and 55 months, respectively. Although the most frequent seizure symptom at onset was motion arrest (50%), atypical and poorly localized symptoms were observed, including cyanosis (33%), epileptic spasms (28%), tonic seizures (28%), and apnea (11%). While 50% of the patients showed focal abnormalities following an EEG analysis, 39% showed atypical bilateral abnormalities, and 11% had normal readings. On initial imaging, an absence of lesions was seen in 44% of the patients. Furthermore, an interictal ^99mTc-ECD SPECT showed either hypo or hyperperfusion in 75% of the patients, while a ¹⁸F-FDG PET showed hypometabolism in the lesions of all patients. Tumors, focal cortical dysplasia, and hippocampal sclerosis occurred in 12 (67%), 3 (17%), and 2 (11%) cases, respectively. Finally, seizures disappeared in 78% of the patients after surgery. A lack of relationship was found between the localization of the preoperative EEG and the seizure prognosis. Conclusions: Although symptoms and EEG findings may be poorly localized in cases of mTLE in infants and young children, resection surgery can successfully improve patient outcomes. Moreover, performing imaging at regular intervals is helpful for the detection of lesions.