Abstract: Objective To explore the clinical features of neck myoclonia with absence seizures in children. Method The clinical and electroencephalogram (EEG) features of neck myoclonia with absence seizures in 2 children were analyzed retrospectively, and the related literature was reviewed. Results Both cases were boys and the age at onset was 7 years and 9 months, 9 years and 10 months respectively. There was no abnormal birth history or growth history, and no family history of genetic diseases or epilepsy. Cranial imaging showed no abnormality. The video-EEG (VEEG) showed no abnormality in the background rhythm, and the anterior head or generalized spinous and slow spinous waves were recorded in the sleep period between attacks. All the episodes were characterized by rhythmic head shaking movement with lateral deflection of the head and neck, accompanied by disturbance of consciousness, lasting about 6 - 13 seconds. During the seizure, the EEG showed a spinous slow-wave rhythmic burst with wide and extremely high amplitudes (about 3 Hz). One side of sternocleidomastoid muscle had about 50 ms of rhythmic myoelectric bursts synchronized with spinous waves, accompanied by tonic potentials. Hyperventilation could induce attack without light sensitivity. There was no abnormality in gene detection. The seizures of the both children were controlled by sodium valproate. Literature search found 4 children reported abroad with neck myoclonus with absence seizures confirmed by VEEG. The seizure was controlled after 4 months to 3 years of treatment with one or two antiepileptic drugs. Conclusion Neck myoclonus with absence seizures is a type of generalized epilepsy with independent EEG clinical characteristics.

Key words: neck myoclonus with absence seizure; epilepsy; video-electroencephalogram