Early-onset spontaneously relieved spasms of infancy in sleep: Electroclinical characteristics and differential diagnoses

Purpose: Infantile spasm-like paroxysms are often difficult to classify as epileptic or non-epileptic. We aimed to study sponta-neously relieved (non-epileptic) spasms of infancy in sleep. Elucidation of the electroclinical characteristics and differential diagnoses of such spasms could facilitate accurate diagnosis in the future. Methods: We retrospectively analyzed the clinical data, video-EEG recordings, and other laboratory test results of patients with spontaneously relieved spasms of infancy during sleep. All the enrolled patients were followed up for at least 5 months. Results: Seven infants were included in this study. The median age at spasm onset was 0.5 months (range: 0.1-2 months). The episodes were characterized by clusters of non-epileptic spasms of the head, trunk, or extremities lasting approximately 0.5-2 s, and were validated by ictal electromyography (EMG)/video EEG. Episodes occurred several times daily in clusters, particularly during sleep; two patients also experienced episodes while awake. Additionally, non-epileptic jerks were recorded in 3 patients. All non -epileptic spasms were completely resolved 2 weeks to 3 months after onset. Moreover, neuropsychomotor development in all patients was normal at the last follow-up (5 to 12 months). Conclusions: Spontaneously relieved spasms of infancy in sleep is a self-limiting movement disorder characterized by onset between 0.1 and 2 months of age, and by clusters of spasms occurring in sleep. Correct differential diagnosis relies on familiar clinical and electrophysiological features.(C) 2022 The Japanese Society of Child Neurology Published by Elsevier B.V. All rights reserved.