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

Abstract

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.

Evaluating the Rate of Recurrence of Epilepsy after Therapy Discontinuation in 2-Year Seizure-Free Epileptic Patients

“…Anderson et al observed that patients with epileptiform waves on their EEG prior to therapy discontinuation were more likely to experience recurrence compared to those who did not have epileptiform waves (67% versus 33%) [16].…”

Withdrawal of antiepileptic drugs in seizure-free adults

“…It found that although the interictal EEG at time of antiepileptic drug withdrawal did not predict recurrence, a worsening of the EEG after withdrawal was predictive of seizure recurrence. 4 …”

“…3 One study reported 63% of patients with partial seizures relapsed on drug withdrawal. 4 Remote symptomatic seizures (defined as seizures occurring in patients with a prior neurologic insult such as head injury, stroke or history of intellectual disability) are associated with a high risk of seizure relapse following discontinuation of therapy. 2 …”

EEG in adults in the laboratory or at the patient's bedside

“…Besides diagnosis and monitoring of the disease, the relevance of EEG has been studied in a third situation: when the epilepsy seems well controlled, with no seizures over the course of several years, can the treatment be stopped and does the EEG have a real predictive value for evaluating the risk of recurrence after treatment withdrawal? The few prospective studies that included EEG in their protocol found a greater risk of seizure recurrence in cases with abnormal EEG [1,30,155], except for two of them, whose negative results might easily be explained by selection bias. Indeed, decision to withdraw or not the treatment was partly based upon EEG results [147], and paroxysmal EEG abnormalities could even be an exclusion factor if generalized [105].…”

“…Indeed, decision to withdraw or not the treatment was partly based upon EEG results [147], and paroxysmal EEG abnormalities could even be an exclusion factor if generalized [105]. Finally, timing seems essential since Tinuper et al [155] found a predictive value when EEG became abnormal during the withdrawal process, but not if the abnormalities were already present before beginning drug withdrawal.…”