MRI hippocampal volume and neuropsychology in epilepsy surgery

A review is provided of recent findings on relationships between neurocognitive test data and magnetic resonance imaging (MRI)-determined hippocampal volumes in nonlesional temporal lobectomy patients. The difference between the right and left hippocampal volumes is correlated with postoperative verbal memory in left temporal lobectomy patients who do not have lesional pathology. MRI hippocampal volume data are not associated with measures of executive functioning or naming. Sex differences have been found for verbal memory outcome as women have better verbal memory following left temporal lobectomy. Sex differences have also been found in the relationships between verbal and visual memory, and hippocampal volume data. The systematic combination of MRI-acquired morphological data and neuropsychological test data may further our understanding of neurocognitive function, and provide clinically useful data for counseling epilepsy surgery patients. The current data are promising with regard to prediction of memory outcome following temporal lobectomy, but they do not yet allow for prediction of specific individual patient outcomes. Rather, the currently available data support counseling patients based on the memory outcome of others with similar characteristics.