Other Phenotypes of Benign Childhood Seizure Susceptibility Syndrome

Abstract

Benign Infantile Focal Epilepsy with Midline Spikes and Waves During Sleep (BIMSE) In 2000, this form was first described as benign focal epilepsy in infancy with vertex spikes and waves during sleep (BVSE, Capovilla and Beccaria 2000). Its electroencephalographic marker had been previously described by Bureau and Maton in 1998 without identification of a new epileptic syndrome. Subsequently, the authors renamed this form as benign infantile focal epilepsy with midline spikes and waves during sleep (BIMSE), to avoid confusion with physiological sleep vertex spikes (Capovilla et al. 2006). All the patients show normal psychomotor development, before and after seizure onset, and neuroradiological studies. Age at onset is comprised between 4 and 30 months, with a peak around 18 months, and seizures disappear between 2 and 4 years. Seizure semiology is typical, characterized by cyanosis, hypotonia, stiffening, and staring. Automatisms, or lateralizing signs are rare. Depending on age, loss of consciousness is often difficult to evaluate by parents. Seizure length is comprised between 1 and 5 min and post-ictal sleep is the rule. Usually, the seizures are sporadic even if, in some cases, the fits repeat for —three to four times in 24–48 h. Seizures occur at awake state, in rare cases during sleep too. Midline spikes appear as low-voltage abnormalities followed by higher bell-shaped slow-waves, isolated or grouped in short sequences. These peculiar EEG findings are evident in midline regions, spreading to central and less frequently temporal regions. They are absent while awake and appear in sleep stage I and II. The disappearance of EEG abnormalities is comprised between 3 and 6 years. This peculiar EEG marker is easy to distinguish, morphologically, both from rolandic abnormalities and physiological sleep vertex spikes. In the evaluation of the EEG records of suspected infants,