Myoclonic jerks are commonly associated with absence seizures in early-onset absence epilepsy.

Typical absence seizures are observed in various epilepsy syndromes, however, few series have focused on early-onset absence epilepsy (EOAE). We aimed to evaluate the occurrence of this seizure type in children under 4 years of age in order to evaluate their electroclinical characteristics and outcome. We retrospectively studied (2006-2014) the electroclinical features of children with normal development and typical absence seizures starting before the age of 4 (with available pre-treatment video-EEG). Nine patients were included. Among them, eight patients had rhythmic myoclonic jerks involving the muscles of the upper face (eyebrows and eyelids) or neck, present from the onset to the end of the typical absence discharge. The myoclonia were synchronous with spike-wave complexes. One patient with GLUT-1 deficiency was refractory to antiepileptic polytherapy. The other eight became seizure-free; five with one antiepileptic drug and three with a combination of two drugs. The treatment was successfully withdrawn in five of the six patients who achieved two years of seizure freedom. None of them exhibited any other seizure type. Four of the eight patients with normal schooling required some support. We observed a positive correlation between the duration of absence seizure and the age of the patient at examination. Most of the patients under four years with only typical absence seizures had EOAE, and the motor symptoms may represent a distinctive age-related feature of EOAE. Further investigations are required to better correlate the role of brain maturation with the duration of the absence. [Published with video sequence on www.epilepticdisorders.com].