Electroclinical aspects and therapy of Han patients with juvenile myoclonic epilepsy in northern China

Abstract

Objective: The objective of this study was to assess the electroclinical aspects and treatment of Han patients with juvenile myoclonic epilepsy (JME) in northern China.

Methods: One hundred fifty-six outpatients with JME from six epilepsy centers, between January 2011 and June 2012, were followed up for at least two years. They underwent twenty-four-hour video-EEG recording. Brain imaging was performed using magnetic resonance imaging (MRI). Clinical aspects, electroencephalographic (EEG) features, and antiepileptic drugs (AEDs) received were reviewed.

Results: Generalized tonic-clonic seizures (GTCS) were found in 150/156 patients. Delay of diagnosis was 4.60±9.92years. Photosensitivity was more common in eye closure condition during IPS in patients with JME; in addition, patients with JME with myoclonic seizures (MS) and GTCS as seizure types were likely to present photoparoxysmal responses (PPRs). The 82 nontreated patients showed a median latency to first interictal or ictal generalized spike-wave discharge (GSWD) of 50min (IQR: 22-102min). The first GSWDs were recorded in 63%, 76%, 90%, and 98% patients within one, two, three, and 4h, respectively; only 2% of patients had first GSWDs after 4h. One hundred eleven patients (111/156) chose extended-release valproate (VPA) at daily doses ≤1000mg. The percentages of seizure-free patients among MS, GTCS, and absence seizure (AS) groups were 88.3%, 99.0%, and 94.9%, respectively.

Conclusion: Photoparoxysmal responses were more common in patients with JME with MS and GTCS and rare in patients with JME with MS and AS in northern Chinese Han patients. Most patients with JME in northern China chose VPA as first therapeutic choice, and low dose (500 to 1000mg daily) of extended-release VPA may be an optimal choice for them. Video-EEG monitoring for at least 4h may be helpful in detecting the first interictal or ictal GSWD in patients with potential JME. Moreover, video-EEG monitoring performed at about 9 o'clock in the morning with patients in the awake state might be useful to find the first GSWD. For JME diagnosis, Class II criteria are more helpful than Class I counterparts, the latter yielding more missed diagnoses.

Keywords: Electroclinical characteristics; Generalized spike–wave discharge; Photoparoxysmal responses; Valproate.