Atypical neuropsychological profiles and cognitive outcome in mesial temporal lobe epilepsy

Patients with left mesial temporal lobe epilepsy (MTLE) have deficits in verbal memory processes, while patients with right MTLE have visuospatial memory impairment. However, atypical cognitive phenotypes among patients with MTLE may occur. In this study, we analyzed preoperative memory deficits in a cohort of 426 right-handed patients with unilateral MTLE. We also evaluated the cognitive outcome after anterior temporal lobectomy (ATL) of patients with atypical profiles in comparison with those with typical memory profile. We found that 25% of our patients had a typical cognitive profile, with verbal memory deficits associated with left side hippocampal sclerosis (HS) and visuospatial memory deficits associated with right side HS. However, 75% of our patients had atypical memory profiles. Despite these atypical profiles, patients submitted to right ATL had no significant cognitive deficit after surgery. In patients submitted to left ATL, the higher the presurgical scores on verbal memory and naming tests, the higher the cognitive decline after surgery.