Chemical shift imaging spectroscopy and memory function in temporal lobe epilepsy

Purpose: Hippocampal neuron loss and associated memory deficits are charact eristic of intractable temporal lobe epilepsy (TLE). Proton chemical shift imaging (CSI) spectroscopy is a sensitive tool for detecting neuronal loss. The aim of this study was to investigate the correlation between memory fu nctions and results provided by CSI spectroscopy of the hippocampal structu res. Methods: Ten patients with cryptogenic TLE participated. The study protocol involved both the acquisition of high-spatial-resolution CSI spectroscopy and neuropsychological evaluation, including memory testing and intracaroti d sodium amytal test (IAT). The analysis of the CSI data was based on norma tive data obtained in 30 healthy volunteers. Memory functions were represen ted by verbal, visual, and general memory indices. Results: A significant correlation was found between CSI spectroscopy of th e hippocampal formation and the verbal memory indices far the dominant hemi sphere. In addition, there was a significant correspondence of the qualitat ive judgment "hippocampal pathology indicated by CSI spectroscopy" and both "material specific memory deficit" and "memory deficit in the IAT." Conclusions: Our results demonstrate that CSI spectroscopy of the hippocamp al structures is strongly related to lateralized memory deficits in patient s with TLE. This suggests that CSI spectroscopy may be useful in the predic tion of postoperative outcome in respect of seizure control and memory.