The prognostic value of the electroencephalogram in antiepileptic drug withdrawal in partial epilepsies.

We evaluated the prognostic value of the EEG in 120 seizure-free epileptic patients (49 with complex partial seizures with or without episodic secondarily generalization [CPS], 20 with simple partial seizures with or without episodic secondarily generalization [SPS], 51 with only secondarily generalized seizures [PSG] during and after antiepileptic drug withdrawal. All patients had EEG examination before; during; and 3, 12, 24, and 36 months after drug withdrawal. Relapse rates were 45% in CPS, 100% in SPS, and 65% in PSG. Before reduction, 36 patients had epileptiform EEG and 69% relapsed; in the group with normal EEG, 60% relapsed. EEG worsened in 36 patients, 83% relapsed, whereas only 54% of patients with unchanged EEG relapsed. EEG during but not at the start of drug withdrawal has a prognostic value in partial epilepsy.