The spectrum of benign infantile seizures

Benign epilepsies during infancy are a wide topic, which needs both clinical and nosological clarifications. Already in 1963 Fukuyama reported patients with seizures during infancy with a benign outcome. In the late 80s and early 90s, Watanabe reported series of infants with complex partial seizures or partial seizures with secondary generalization, with a normal development before onset and a benign outcome. In the same years Vigevano focused on familial cases: he described several families with seizures with onset around the 6-month of age, and autosomal dominant mode of inheritance. To define this condition, he coined the term "benign familial infantile seizures" (BFIS). Afterwards, studying families with this phenotype, loci on chromosomes 19, 16 and 2 responsible for BFIS were detected. Similar loci were found in families affected by BFIS and subsequent choreoathetosis, and BFIS associated with familial hemiplegic migraine. In most recent years a new form of benign epilepsy has been proposed, with an intermediate onset between the neonatal and infantile age, which was defined with the term benign familial neonatal-infantile seizures (BFNIS). This condition could have some clinical and genetic features overlapping with BFIS. Seizures with a benign outcome have been reported also in infants during episode of mild gastroenteritis (BIS with MG) frequently with positive Rotavirus antigen. Lastly, sleep EEG abnormalities have been reported in children with a peculiar form of epilepsy by Capovilla, who defined this condition as benign infantile focal epilepsy with midline spikes and waves during sleep (BIMSE). Some of these entities have been included in the last classification proposed by the ILAE and have been differentiated in familial and non-familial forms. The aim of this review is to describe these entities, discuss their nosological aspects, pointing out the similarities and differences with benign neonatal seizures and benign focal epilepsies appearing later in life such as early-onset benign occipital seizure susceptibility syndrome (EBOSS), or benign epilepsy of childhood with centro-temporal spikes (BECTS).