A rare epilepsy syndrome characterised by late-onset (after 1 year old) epileptic spasms that occur in clusters, associated with tonic seizures, atypical absences and cognitive deterioration. Language difficulties and behaviour problems are frequently present. EEG is characterised by a temporal or temporofrontal slow wave or spike focus combined with synchronous spike-waves and no hypsarrhythmia or background activity. [from
SNOMEDCT_US]