Abstracts

Rationale: "Drop attacks" have been observed in a number of different seizure types. However, they are remarkably brief and dramatic due not only to the seizure itself but also to gravity, such that it is often difficult to make an exact seizure diagnosis based on a witness description. Recent progress in electrophysiological devices has demonstrated that atonic seizures, myoclonic-atonic seizures, and epileptic (flexor) spasms are the main seizure types causing drop attacks. We report herein a special type of drop attack associated with an initial vocalization in children with cryptogenic myoclonic-astatic epilepsy (CMAE). Methods: The subjects were 5 patients (male: 2, female: 3) whose epilepsy was ultimately diagnosed as CMAE. Drop attacks with an initial vocalization were investigated employing simultaneous video and electroencephalography-electromyography (EEG-EMG) recordings. All events were analyzed in slow motion and frame-by-frame video replay mode. Results: The video-polygraphic examination captured a total of 36 drop attacks in these 5 cases. There were 24 drop attacks associated with brief vocalizations. Detailed analyses demonstrated that all were classifiable as myoclonic-atonic seizures with or without the preceding initial vocalizations, which precisely corresponded to myoclonic EMG components of the myoclonic-atonic seizures. The ictal EEG showed generalized spike-and-wave or polyspike-and-wave complexes. Conclusions: Drop attacks associated with an initial brief vocalization were found to be myoclonic-atonic seizures whose myoclonic component appeared to momentarily involve the thorax, thereby producing the brief vocalization. Myoclonic-atonic seizures preceded by vocalizations are also the main seizure type of CMAE and should be considered in the differential diagnosis of drop attacks in childhood epilepsy.