Myoclonic seizures mimicking epileptic spasms: An infant case with semi‐rhythmic jerks

Myoclonic epilepsy in infancy (MEI) is a rare epilepsy characterized by myoclonic seizures that begin between 4 months and 3 years of age.1-3 These seizures occur during wakefulness or drowsiness, mainly involving the upper limbs and head, and may appear in clusters, making their differentiation from epileptic spasms difficult1-3 (Video 1). Epileptic spasms are the hallmark of infantile epileptic spasms syndrome (IESS), which may lead to developmental stagnation or regression. Early diagnosis and treatment of IESS are crucial, even when developmental delay or typical hypsarrhythmia is absent.1 Therefore, distinguishing between seizure types is essential. Myoclonic seizures show brief electromyographic (EMG) bursts (<50 ms) without sustained tonic components, whereas epileptic spasms consist of an initial phasic contraction (<2 s) followed by a less intense tonic phase lasting 2–10 s4-6 (Table 1). These features aid in accurate diagnosis. We thank the patient and his family for their participation and for providing consent for the publication of this case report. The authors declare no conflicts of interest. The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions. Data S1: Tanaka, teaching slides. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article. Answers may be found in the supporting information.