Benign myoclonus of early infancy or benign non-epileptic infantile spasms.

Lombroso and Fejerman (1983) described a syndrome which shares with West syndrome the clinical features of flexion spasm with onset in early infancy. However the syndrome differs from West syndrome in the absence of mental and psycho-motor involvement and having a normal EEG during wakefulness and sleep. We report four cases of these benign spasms of early infancy with polygraphic recording of the spasms providing the following information: the spasms are clinically similar to those often observed in West syndrome; namely they are characterized by a short (2-4 sec.) tonic contraction, there are no significant changes of the EEG concomitant to the spasm, series of spasms can occur not only during the daytime but also during sleep and immediately after awakening. Differential diagnosis is discussed with West syndrome and benign myoclonic epilepsy in infancy and with non-epileptic syndromes. The authors propose to name this syndrome: Benign Non-Epileptic Infantile Spasms.