Nonepileptic myoclonus of infancy and early childhood (an observation of 33 patients)

Abstract

Fejerman syndrome, a benign nonepileptic myoclonus of infancy (BNMI), is a rare type of paroxysmal events, which mimics epileptic spasms. It is difficult to determine the nature of myoclonus without video electroencephalography (VEEG) monitoring. Objective: to present the clinical and electroencephalographic characteristics of new cases of benign nonepileptic myoclonus of infancy and early childhood. Patients and methods. The data of 33 children (19 boys and 14 girls) aged 5 months to 3 years with BNMI, who had been followed in 2011 to 2017, were analyzed. Results and discussion. The age at onset of paroxysms ranged from 4 to 24 months and that was 5–8 months in most cases. The most common movements were extensor muscle jerks (30.3%), head titubation with rotation (27.3%), axial spasms (27.3%), and nods (24.2%). The same child may have different types of paroxysms. Motor paroxysms were sporadic in all the patients and formed into clusters in 33.3% of cases. The frequency of clusters was up to 10 times daily. There were 2 to 50 paroxysms in the cluster. There was delayed psychomotor development in 5 of the 33 children and hyperexcitability was present in 10. VEEG monitoring indicated that the brain bioelectrical activity conformed to the age in 97% of cases; none of the children showed abnormal movements accompanied by EEG pathological activity. The duration of the disease was 2 to 19 months, averaging 7 months. In all cases paroxysms were stopped without using antiepileptic drugs. Conclusion. It is extremely important to timely recognize BNMI, since anti-epileptic therapy can be unreasonably prescribed in cases of an erroneous diagnosis. VEEG monitoring plays a crucial role in diagnosing nonepileptic and epileptic myoclonus.