Department of Pediatrics, Tokyo Women's Medical University, Tokyo 162, Japan
Epilepsy Center, TMG Asaka Medical Center, 1340-1 Mizonuma, Asaka-city, Saitama 351-0023, Japan
Yotsugi Medical Center for the Severely Disabled, 4-44-1-101 Higashiyotsugi, Katsushika-Ku, Tokyo 124-0024, Japan
Correspondence: Hirokazu Oguni
Department of Pediatrics,
Tokyo Women's Medical University,
8-1 Kawada-cho, Shinjuku-ku,
Tokyo 162-8666, Japan
The aim of this study was to investigate ictal vocalizations associated with myoclonic (MS) and myoclonic-atonic seizures (MAS) in patients with myoclonic epilepsy in infants (MEI) and epilepsy with myoclonic-atonic seizures (EMAS, Doose syndrome), respectively.
Subjects were retrospectively recruited among patients with MEI and EMAS for whom ictal video-polygraphs were recorded between 1990 and 2019. We reviewed all MS and MAS in order to estimate how often they were associated with vocalizations, and analyze the temporal relationship between vocalizations and spike-wave complexes (SWCs) and myoclonic EMG potentials based on simultaneous examination of the polygraphs and sound signals.
Ictal video-polygraphs from 15 patients with MEI (2-34 MS per patient) and 26 with EMAS (2-26 MAS per patient) were examined. Ictal vocalizations were audible in two patients with MEI (11%; 3-18 MS per patient) and nine with EMAS (35%; 2-11 MAS per patient). Sounds were always non-speech and were immediately followed by head or body dropping in the case of MAS. Detailed analysis based on simultaneous and synchronous examination of video-polygraphs and sound signals in one patient with MEI and five patients with EMAS demonstrated that the onset of the ictal vocalizations corresponded to that of the myoclonic EMG potentials and negative spike components of SWC. Comparison of the length of myoclonic EMG potentials as well as the strength of drop seizures between MAS with and without vocalizations revealed that MAS with vocalizations were associated with longer myoclonic EMG potentials and stronger drop seizures than MAS without vocalizations (p<0.05), suggesting that the vocalizations result from strong contraction of axial muscles.
Ictal vocalizations due to massive motor seizure activity are a relatively common finding in MAS in Doose syndrome, which may help in the differential diagnosis of epileptic drop attacks.