[P2-76] Chronological changes in electroencephalogram features of three cases with progressive myoclonus epilepsy
[Introduction] Children with Huntington disease (HD) and dentatorubral-pallidoluysian atrophy (DRPLA) are known to present progressive myoclonus epilepsy (PME), a devastating form of epilepsy with heterogeneous etiologies. We herein report chronological changes in electroencephalogram (EEG) features for a case with HD and two siblings with DRPLA. [Case Reports] Case 1. A girl with HD suffered from intractable epilepsy since 8 years of age. At 10 years of age, EEG showed a unique pattern of paroxysmal activity resembling periodic lateralized epileptic discharges. Case 2. An 11-years-old girl with DRPLA developed intractable epilepsy since 3 years of age. Paroxysmal activity was noticed on EEG at the age of 7, while periodic synchronization of epileptiform discharges were barely seen. The EEG at 11 years of age was dominated by clustered segments of high-voltage, slow waves and epileptic discharges that were frequently synchronized and occasionally showed periodicity. Case 3. A one-year-older brother of Case 2 with DRPLA had the onset of epilepsy at 8 years of age. The EEG at 10 years of age showed irregular backgrounds and diffuse multifocal spike-and-wave complex formations with few periodic synchronization. He had progressive signs of cerebellar ataxia while his seizure increased in frequency by 12 years of age. Serial EEGs revealed prominent features of diffuse paroxysmal discharges with periodically synchronized electrical activity. [Conclusion] Periodic complexes in electroencephalography may emerge at advanced stages of childhood PME as a consequence of rapidly degenerating processes of their brain functions.