The pathogenesis of hippocampal sclerosis may involve an injury acquired during early life (when the patient is younger than 5 years of age) combined with primary or secondary hippocampal atrophy associated with chronic epilepsy.38 Previous reports, however, have suggested that up to 15% of patients with the diagnosis of MTLE may have normal hippocampal volumes on MR imaging.26 This subgroup of patients presents with clinical and scalp EEG findings consistent with MTLE but, paradoxically, no appreciable hippocampal atrophy or signal changes on T2-weighted MR images, even though the hippocampus is considered the most likely electrographic seizure generator observed during long-term intracranial electrode monitoring. We have designated this subgroup of MTLE as PTLE. We have previously reported immunohistopathological changes in a similar group of patients.13 In this report, we attempt to define clinical, electrophysiological, and additional pathological characteristics of patients with PTLE and provide an analysis of surgical outcomes in these patients.
Williamson PDFrench JAThadani VMKim JHNovelly RASpencer SSet al: Characteristics of medial temporal lobe epilepsy: II. Interictal and ictal scalp electroencephalography, neuropsychological testing, neuroimaging, surgical results, and pathology. Ann Neurol 34:781–7871993Ann Neurol 34: