Infantile spasms are either due to a variety of known etiological factors (symptomatic (v. symptomatic West Syndrome)), or are without apparent causes (idiopathic/cryptogenic (v. cryptogenic West Syndrome)). Some authors suggest a distinction between cryptogenic and idiopathic: idiopathic referring to patients with a possible hereditary predisposition, such as a family history of epilepsy or febrile seizures or EEG genetic patterns, and cryptogenic referring to patients with a presumed underlying etiology, that cannot be demonstrated (Dulac et al 1993; Vigevano et al 1993)