Eyelid myoclonia with absences: Routine EEG is sufficient to make a diagnosis

Abstract

To identify the prevalence, clinical characteristics and routine EEG features of the syndrome of eyelid myoclonia with absences (EMA) using a retrospective case control study design. EEGs from 1996 to 2005 were searched using the following keywords: eyelid flutter, eyelid blinking, tics, idiopathic generalized epilepsy, clinical absence, atypical absence and photoparoxysmal response. During the same period, patients with a diagnosis of idiopathic generalized epilepsy were identified. Patients with mainly eyelid fluttering/eyelid blinking as their seizure semiology were divided into EMA and non-EMA groups using previously published criteria and compared using parametric (Student's t-test) and non-parametric tests (Chi square) where appropriate. A p-value of <0.05 was considered significant. The keywords identified 997 patients, 288 patients were diagnosed with idiopathic generalized epilepsy; 126 had eyelid fluttering/blinking as their major seizure semiology. After excluding 51 patients due to incomplete data, of 75 remaining patients, 26 (9.03%) had EMA. Patients with EMA were (1) older at time of first EEG (OR=2.86; 95% CI=7.00-10.23; p=0.005) (2) more likely to have an event on routine EEG (OR=3.62; 95% CI=1.28-10.19; p=0.01) (3) had >3 events per day (OR=9.73; 95% CI=2.06-45.96; p=0.0012) (4) had higher prevalence of developmental delay (OR=4.46; 95% CI=1.36-14.67; p=0.01) and (5) had normal EEG background compared to the non-EMA group. EMA is not uncommon; diagnosis can be made with good clinical history and routine EEG. As developmental delay is a common association with EMA in this study, early identification and treatment are important.