MRI extrahippocampal volumes and visual memory: Correlations independent of MRI hippocampal volumes in temporal lobe epilepsy patients

Limbic system atrophy and memory dysfunction are common in patients with te mporal lobe epilepsy (TLE). However, the relationship between extrahippocam pal Limbic structures and memory functioning within TLE has received little attention. The present study examined associations of Mill volumetric meas urements of the mammillary body, fornix, amygdala, and hippocampus to measu res of episodic verbal and visual memory. The Logical Memory and Visual Rep roduction subtests from the Wechsler Memory Scale were administered to 47 u nilateral TLE patients (25 right, 22 left). Normalized right and left MRI: volumes were determined for each patient by cursor tracing 1.5 mm slices fr om 3D-MRI. Significant associations were found between left hippocampal vol ume and the immediate, delayed, and percent retention scares of the Logical Memory Test; between the left mamillary body volume and the Logical Memory Test delayed and percent retention scores; immediate Visual Reproduction p erformance was significantly related to the right and left amygdala volumes , and right mammillary body volume; only the right amygdala and right mammi llary body volume were associated with the delayed Visual Reproduction tria l. However, neither right nor left hippocampal volumes were related to visu al memory performance. Multiple limbic system structural volumes were indep endently associated with verbal and nonverbal memory performance. Results s uggest that visual memory, as measured by the Visual Reproduction Test, may be uniquely associated with extrahippocampal volumes in patients with TLE.