Visual learning deficits in nonresected patients with right temporal lobe epilepsy.

A visual learning test Diagnostikum für Zerebralschäden (DCS) was revised and applied to three matched patient groups defined by interictal and ictal EEG findings: 24 patients with left temporal lobe epilepsy (LTE), 19 patients with right temporal lobe epilepsy (RTE) and 34 patients with a bitemporal epileptic involvement (BTE). Fifty seven healthy subjects served as controls. Performance on a measure of sustained attention and visual construction was also assessed. Results were as follows: (1) In contrast to controls and LTE patients, patients with right temporal epileptic involvement (RTE/BTE) showed a significantly reduced immediate recall as well as a reduced learning capacity and mean learning performance. (2) Patients made significantly more errors than controls, with RTE patients exhibiting the most visuo-spatial errors. (3) RTE/BTE patients additionally showed impaired performances on visuo-construction, but when visual construction scores were used as covariate, they did not diminish the strong group effects upon learning. (4) Attentional deficits were independent from memory deficits and rather reflected the bitemporal extention of epilepsy. As a conclusion, the data suggest an impairment of visual-spatial consolidation processes in patients with right temporal lobe epilepsy.