Abstracts

Neuroimaging research in temporal lobe epilepsy (TLE) has documented that verbal material-specific functioning is often associated with the integrity of the hippocampal structures in the language dominant hemisphere. However, similar research has produced inconsistent empirical support that nonverbal material-specific functioning is associated with the integrity of nondominant hippocampal structures. We hypothesized that decreasing perceptual-motor clustering performances on a complex design copying task would be correlated with right, as compared to left, hippocampal volumes in patients with intractable TLE. We evaluated 45 patients with intractable, unilateral TLE and left hemisphere language dominance. We scored each patient[apos]s design copying performance on the Rey-Osterrieth Complex Figure Test using a perceptual-motor clustering scoring system. We obtained hippocampal volumes from T2-weighted MRI images using our previously published protocol and evaluated the correlation between perceptual-motor clustering and hippocampal volumes. We found that decreased design copying performances were significantly correlated with decreasing right (p [lt] .05), but not left (p [gt] .20), hippocampal volumes. These results were significant after statistically removing the effects of the WAIS-R Full Scale IQ and chronicity of seizures. Our findings, using a perceptual-motor clustering scoring system, document a previously unreported relationship between design copying and right, but not left, hippocampal volumes in patients with unilateral TLE. Although constructional praxia is generally believed to be more closely related to parietal lobe functioning, the current results are consistent with hypothetical contributions of anterior and inferior-mesial structures in visual-motor and perceptual-organizational functioning.