Neuropsychological Aspects of Severe Myoclonic Epilepsy in Infancy

Abstract

Severe Myoclonic Epilepsy in Infancy (SMEI) was first described in 198212 and rec- ognized as a syndrome in 1989.7 This disorder is characterized by 1) a high familial inci- dence of epilepsy or febrile convulsions; 2) repeated convulsive seizures from the middle of the first year of life, that are clonic or tonic-clonic, either generalized or unilateral, and often prolonged; 3) the later occurrence of myoclonic jerks, atypical absences and partial seizures; 4) a progressive slowness of psychomotor development during the second year; 5) behavioral problems including hyperkinesia and poor interpersonal relationships. To date, no underlying pathology or degenerative disease has been identified. This epilepsy is cryptogenic, affecting patients who were considered normal at the onset. Treat- ment is difficult and seizures persist into the adult age. We reviewed the neuropsycho- logical course of 20 patients diagnosed as suffering from SMEI at the Centre Saint-Paul in Marseilles. In some cases, it was possible to correlate characteristics of the epilepsy (including seizure pattern and EEG features) to the neuropsychological pattern. Col- lecting detailed information on the neuropsychological development of these children may contribute to the understanding of mechanisms involved in both the deterioration and recovery of cognitive functions. 1.