Pre-attentive cognitive processing in epilepsy. A pilot study on the impact of epilepsy type and anti-epileptic treatment

Patients suffering from epilepsy often complain of deficits in attentive cognition affecting, for instance, concentration, reaction time, memory and psychomotor speed. We were interested in the impact of epilepsy and its treatment on pre-attentive cognitive functions and enrolled 107 subjects (50 male, 57 female; mean age 26 years): 50 patients with partial epilepsy, 15 with primary generalised epilepsy and 42 healthy controls. We used a new computer-adapted neuropsychological test (called textest), measuring the pre-attentive visual processing speed. The subjects had to discriminate 5 different stimuli presented on a computer screen. As a primary result, we calculated the time the subject needed to detect 50% of the demonstrated stimuli correctly (t-50 time). We also applied the d2 test. For the textest results, no significant group differences between the different patient and healthy groups could be revealed, except for a significantly increased t-50 time in patients with polytherapy compared with the control group. Compared with healthy controls, significantly worse d2 test results were found in patients with epilepsy in general, a duration of disease >1 year, anti-epileptic drug therapy in general and in patients receiving polytherapy in particular (all p < 0.001). Our data suggest that polytherapy, but not monotherapy or the subtype of epilepsy, might have a slowing impact on pre-attentive cognitive processing.