Abstracts

RATIONALE: Quantitatively evaluating the rapid withdrawal effects of lamotrigine (LTG) and carbamazepine (CBZ) on ictal seizures during presurgical evaluation in patients with pharmacoresistant partial epilepsy.
METHODS: The duration, intensity and frequency ictal seizure phenomena of 41 patients totally withdrawing from CBZ monotherapy (n=20), LTG monotherapy (n=10) and CBZ and LTG combined therapy (n=11) were intensively studied by TISA (therapeutic intensive seizure analysis) method. Study phases ran from the baseline phase to the AED withdrawal phase until the AED free phase, three days for each phase.
RESULTS: Seizure duration and frequency obviously increased during the withdrawal process in each group (p[lt]0.05). No change of seizure intensity was observed. Prolongation in duration of ictal signs like hypermotoric, oro-alimentary automatisms, fumbling and ictal speech were significant in each group (p[lt]0.05), especially during the AED free phase. The duration and intensity of secondarily generalized clonic signs markedly increased with the tapering of each drug, tonic signs, however, only in the AED free phase (p[lt]0.05). The frequency of all ictal signs only increased in the CBZ and CBZ+LTG group. Intergroup comparisons of all variables were insignificant (p[gt]0.05). There was no change of ictal EEG localization during each withdrawal protocol.
CONCLUSIONS: All patients experienced increased duration and frequency during the withdrawal processes without an obvious change of seizure intensity. Prolonged duration and frequency of ictal automatisms, ictal speech and hypermotoric signs were mostly observed during the AED free phase. A discrepancy exists in the later part of the seizure structure during the secondary generalization. Tonic signs increased more in the AED free phase, whereas clonic sign already began from the AED withdrawal phase. Difference between the withdrawal effects of LTG monotherapy and CBZ monotherapy and polytherapy is mainly in the frequency change of ictal signs.