Please refer to specific syndromes and etiologies in which this seizure type occurs for specific information. As a general rule, EEG abnormality may be first evident / enhanced in sleep and on wakening.
Epileptic spasms are most commonly accompanied by a high voltage triphasic sharp or slow wave followed by low amplitude fast activity and voltage attenuation. The EEG pattern may be generalized (for generalized epileptic spasms) or seen focally (for focal epileptic spasms). This EEG pattern may be seen in sleep with or without clinical seizures seen.