Repetitive sleep starts: An important differential diagnosis of infantile spasms.

Abstract Objective Repetitive sleep starts (RSS) are clusters of nonepileptic, spasm-like movements occurring during sleep onset. However, their characteristics have yet to be defined. We conducted a clinicoelectroencephalographic study of children with RSS to clarify their detailed characteristics. Methods To differentiate starts from epileptic spasms, we recruited children with brief “crescendo–decrescendo” muscle contractions that simultaneously involved the limbs and trunk without electroencephalogram changes, and that fulfilled the following criteria: (1) repeated occurrence (five or more) and (2) manifestation during sleep stage N1–N2. A total of nine children met these criteria. Their clinical information and video-electroencephalogram data were analyzed retrospectively. Results The background conditions observed at onset of RSS were perinatal hypoxic–ischemic encephalopathy (n = 4), West syndrome of unknown etiology (n = 1), and traumatic brain injury (n = 1). The age at onset of RSS, the number of starts in a given RSS cluster, the interval between starts, and the duration of surface electromyogram activity were between 3 and 46 months, 5 and 547, Conclusion This is the largest case series of RSS clarifying their clinicoelectroencephalographic characteristics reported to date. To avoid unnecessary antiepileptic therapies, clinicians should be aware of RSS and distinguish it from other disorders involving involuntary movements or seizures, especially epileptic spasms.