NEUROPSYCHOLOGICAL CHARACTERISTICS OF THE SYNDROME OF MESIAL TEMPORAL-LOBE EPILEPSY

Objective: To identify the neuropsychological features of the syndrome of mesial temporal lobe epilepsy (MTLE), a surgically remediable epil eptic syndrome defined by the presence of hippocampal sclerosis, using a broad and comprehensive neuropsychological test battery. Setting: E pilepsy surgery center. Patients: After scalp and invasive electroence phalographic monitoring, a consecutive series of 107 adults were found to have intractable complex partial seizures of unilateral left (n=62 ) or right (n=45) temporal lobe origin. Patients were included if they were not retarded and had left hemisphere dominance for speech but no magnetic resonance imaging abnormalities other than hippocampal scler osis. Histopathological analyses of resected hippocamppi showed that 6 6 patients had hippocampal sclerosis (MTLE+), and 41 did not have evid ence of significant hippocampal sclerosis (MTLE-). Interventions: None . Main Dependent Measures: A comprehensive battery of neuropsychologic al tests that included measures of intelligence, academic achievement, language, visuoperceptual or visuospatial function, memory and learni ng, attention, and problem-solving abilities. Results: The syndrome of MTLE was associated with considerable generalized cognitive impairmen t (in intelligence, academic achievement, language, and visuospatial f unctions), but not related to adequacy of performances in other select ed cognitive domains (attention or concentration, executive functions) . Material-specific memory effects were obtained--primarily for verbal memory in association with left-sided MTLE. Conclusions: Distinct neu ropsychological features of spared, compromised, and laterality-specif ic cognitive impairments characterize the syndrome of MTLE. This infor mation needs to be incorporated into formal syndrome criteria.