Neuropsychological heterogeneity in patients with mesial temporal lobe epilepsy

Introduction. Cognitive dysfunction in mesial temporal lobe epilepsy (MTLE) is still a cantroversal subject. Since refractory MTLE is considered a surgically remediable syndrome, the neuropsychological assessment to establish the presence of cognitive impairment in the surgical candidate became an important issue, given its possible relevance in predicting outcome after surgery. Objective. Our aim was to study the cognitive profile of MTLE patients and to correlate the cognitive status with the presence or absence of hippocampal sclerosis. Patients and methods, Fifty patients with MTLE and 20 control subjects were matched by age and educational level. All subjects were studied with EEC, MRI scan, SPECT, and a comprehensive neuropsychological battery that included measures of language (naming and verbal fluency), visuospatial function (Block Design Test), memory (Signoret Battery), attention (Digit Span and Trail Making Test A) and executive abilities (Trail Making Test B and Wisconsin Card Sorting Test). Results. MTLE patients, particularly those with hippocampal sclerosis, were found to have a considerable lower performance in learning (p< 0.01), naming (p< 0.05), attention (p< 0.05) and executive functions (p< 0.001). Among the MTLE patients a considerable number of subjects showed results within the normal range (n= 27) while others evidenced laterality specific cognitive impairments (n= 13). Material specific memory effects were seen in some patients but not all. Conclusions. Our results showed the neuropsychological heterogeneity of temporal lobe epilepsy, thus ruling out the existence of a single specific cognitive pattern of impairment in all MTLE patients, and suggesting the need of a thorough pre-surgical neuropsychological evaluation to be used with post-surgical prognosis purposes [REV NEUROL, 1999; 29: 1160-3].