Effects of temporal lobe epilepsy on spatial and figural aspects of memory for a complex geometric figure

The preoperative delayed memory performance on the Rey-Osterrieth Complex Figure (Lezak, 1983) of 54 patients with complex partial seizures of temporal lobe origin was analyzed using 3 different indices. One index (composite) was derived using a common scoring method that included both spatial and figural aspects of memory in its score. The other two indices were derived emphasizing either spatial or figural aspects of memory for the elements of the figure separately. All 3 indices distinguished between individuals with right-sided (RTLE) and left-sided (LTLE) seizure onset. However, spatial memory was significantly lower than figural memory in individuals with RTLE as compared to those with LTLE. Both the spatial and figural memory indices were significantly lower in the presence of magnetic resonance imaging (MRI) evidence for hippocampal sclerosis in individuals with RTLE. Results suggest that while both the spatial and figural aspects of nonverbal memory are sensitive to right hippocampal dysfunction, figural memory may be less vulnerable to the effects of RTLE.