Short-term withdrawal of antiepileptic medication: effects on attention and memory

The aim of this study was to determine the effect of routine withdrawal of antiepileptic drugs (AEDs) during preoperative evaluation on cognitive functions and also to clarify whether short-term withdrawal of AED would help to lateralize the epileptic focus and to highlight focal dysfunction of memory in patients with temporal lobe epilepsy.

Cognitive function was evaluated in 25 patients on full medication and after 1-week during the ongoing AED withdrawal. Six additional patients without AED withdrawal were studied during the same time interval and served as controls. The effect of AED withdrawal on memory tests was evaluated in a subgroup of 11 patients with temporal lobe epilepsy (TLE group).

In the TLE group, verbal recurrent-sequences learning tasks deteriorated significantly in patients with left-sided foci during AED withdrawal. In the whole group, attention, concentration and mental flexibility improved both in patients and in controls; the improvement was interpreted as being the result of the practice effect. During AED withdrawal, the number of errors in these tests decreased or remained unchanged.

We suggest that preoperative neuropsychological testing can be scheduled at any time in patients referred for epilepsy surgery. In patients with temporal lobe epilepsy, the lateralizing results of selective memory tests may be most reliable if the testing is performed during AED withdrawal.