Focal clinical and electroencephalographic features in patients with juvenile myoclonic epilepsy.

Objective: To identify prevalence and factors associated with occurrence of focal clinical and electroencephalogram (EEG) abnormalities in patients with juvenile myoclonic epilepsy (JME).
Materials and Methods: Clinical asymmetries in the seizures and focal EEG abnormalities were analyzed in 266 patients with JME.
Results: All the patients had myoclonic jerks (MJ) and generalized tonic-clonic seizures (GTCS); 56 (21%) had absence seizures. Asymmetry in clinical seizures was reported in 45 (16.9%) and focal EEG abnormalities were noted in 92 (45.5%) patients. Amplitude asymmetry or focal onset of generalized discharges was noted in 41 (44.6%) and independent focal EEG abnormalities in 30 (32.6%) patients. A statistically significant association was seen with the presence of GTCS and MJ (P = 0.007), a family history of epilepsy (P = 0.001) and drug resistance (P = 0.04) and the occurrence of focal EEG abnormalities.
Conclusion: Patients with JME showed focal clinical and EEG features. These features should not be misinterpreted as indicative of partial epilepsy.
((c) 2009 The Authors Journal compilation (c) 2009 Blackwell Munksgaard.)