Temporal lobe epilepsy does not impair visual perception

Temporal lobe epilepsy (TLE) can impair interictal cognitive function. In the perceptual domain, previous psychophysical studies demonstrated specific deficits in auditory and tactile perception in patients with TLE. This study compared performance of 25 TLE subjects and 27 controls on two low-level, visual tasks: luminance discrimination and frequency discrimination. Both tasks were performed under a relatively easy and a relatively difficult condition, by adjusting the stimulus duration. TLE subjects performed as well as controls on both tasks at both stimulus durations. These results imply that interictal occipital lobe function, as reflected in performance on low-level visual tasks, is not impaired in TLE, consistent with functional imaging data. Furthermore, since TLE subjects performed normally while taking therapeutic doses of multiple AEDs, the data suggest that these AEDs do not impair visual perception.