Unique clinical phenomenology can help distinguish primary from secondary generalized seizures in children

The physical manifestations a seizure produces provide critical information. It is assumed that all generalized convulsions are ostensibly the same, regardless of whether they are primary or secondary generalized seizures. We undertook a pilot study to determine if the clinical phenomenology of secondary generalized seizures in children with epilepsy is different from classic descriptions of generalized tonic-clonic convulsions. A data capture sheet was created and applied to the video-electroencephalographic (EEG) records of 64 secondary generalized seizures from 13 children with intractable and/or refractory epilepsy. Many features of secondary generalized seizures were different from traditional descriptions of generalized convulsions. In 100% of cases, the mouth either remained open or repeatedly opened and closed rather than slamming shut. In 77% of cases, a variety of late motor activities were seen to occur after the seizure activity had ceased and the EEG record was quiet. The clinical features of a generalized convulsion in a child, especially mouth opening and late motor events, can be useful in establishing the origin as either focal or primary generalized.