Abstracts

Rationale: Cognitive impairment in epilepsy patients is variable and can be induced by antiepileptic drug. To evaluate the changes of attention after levetiracetam administration, we measured the P300 and Continuous Performance Tests (CPT) in newly diagnosed epilepsy patients before and after levetiracetam medication. Methods: Auditory & visual P300 studies and CPT were performed in 15 newly diagnosed patients (M:F=8:7, mean age 28.6 ± 8.8 years) and 16 healthy control M:F=8:8, mean age 28.9 ± 10.5 years). Epilepsy patients had repeated auditory & visual P300 studies and CPT two months since levetiracetam treatment (1000-1500mg/day) was started. For auditory P300 recordings, patients were presented with tones at two different frequencies (1 and 2 kHz) using earphones. The non-target stimulus (1 kHz) occurred 80%, and the target stimuli (2 kHz) were randomly interspersed with the non-target stimuli at a probability of 20%. For visual P300 recordings, a small circle was a frequent stimulus and a large circle a rare stimulus. We performed three steps of CPT. In the first step, 428 letters were presented in rapid succession. When the target “X”, “Y” or “Z” appeared, the patient pushed a button as quickly as he or she can. In the second and third steps of CPT, 408 letters were presented. Subjects responded to the letter “X” or “Y” (second trial) and “X”, “Y”, or “Z” (third trial) only when they were presented in order. The target stimulus occurred 20% and were randomly presented. Results: Mean auditory P300 latency was significantly prolonged at electrode F3, FC3, TP7, CPz, P3, Pz, Oz (p=0.035~0.044) in epilepsy patients compared to that of normal controls. But there were no differences in mean visual P300 latency, mean amplitudes of auditory and visual P300s between epilepsy patients and control group (p >0.05). In all three steps of CPT, mean correction rate was non-significantly lower in epilepsy patients than that in control group (p>0.05). After levetiracetam treatment, the auditory P300 latency was significantly prolonged at electrode T7, C4, T8, TP7, CPz, P7, P3, Pz, P4 (Wilcoxon Signed ranks Test, p=0.009~0.029). The visual P300 latency, amplitudes of auditory and visual P300 were not changed by levetiracetam administration (p>0.05). After levetiracetam medication, the correction rate was significantly increased in the first step of CPT (Wilcoxon Signed ranks Test, p=0.008~0.009). In the second and third steps, the correction rate was non-significantly increased (p>0.05). Conclusions: The mean latency of auditory P300 was significantly prolonged in epilepsy patients compared to healthy controls. A long-term administration of levetiracetam indcuced a prolongation of auditory P300 latency but the improvement of Continuous Performance Test in newly diagnosed epilepsy patients.