Myoclonic astatic epilepsy: an age-dependent epileptic syndrome with favorable seizure outcome but variable cognitive evolution

Abstract

The objective of the study was to explore clinical, electroencephalography (EEG), neuropsychological features and prognosis of myoclonic-astatic epilepsy (MAE). Of 327 children aged between 1 and 9 years with a diagnosis of generalized epilepsy followed between 2000 and 2008, 18 (5.5%) had MAE. Male significantly predominated (88.9%). Age at onset ranged from 2.3 to 4.9 years (mean 3.6 years). Median follow-up period was 6.3 years. In addition to myoclonic-astatic seizures patients had myoclonic seizures (66.7%), drop attacks (72.2%), head drops (77.8%) absences (88.9%), tonic-clonic generalized seizure (77.8%), tonic seizures (38.9%), non-convulsive status epilepticus (16.7%). Seven patients (38.9%) had an epileptic encephalopathy. At onset, interictal epileptiform and slow abnormalities were recorded, respectively, in 100% and 77.8% of patients. EEG abnormalities disappeared in all patients within 4 years since the onset. At long-term follow-up, two patients developed focal abnormalities typical of rolandic epilepsy and two patients photosensitivity. On neuropsychological testing 66.7% of patients had a normal IQ (mean 81.2±17.0, range 47-105, median 84.5) after a mean period of 4.4 years since the last seizure. Sixteen out of 18 patients remitted within 3.5 years since the onset and in two patients tonic seizures persisted. MAE is generalized childhood epilepsy: although cognitive functions might deteriorate, outcome is good regarding seizures.