Benign Myoclonus of Early Infancy
(Benign Infantile Spasms)
Benign myoclonus of early infancy (BMEI) is characterized
by episodes of myoclonic spasms involving flexion
of the trunk, neck, and extremities in a manner
resembling the infantile spasms of West syndrome.7,8
The myoclonic spasms typically occur in clusters.
In some cases they involve a shuddering movement of
the head and shoulders, and in others the movements
of the trunk and limbs are extensor.9 There is no change
in consciousness during the spells. Unlike benign neonatal
sleep myoclonus, the movements in BMEI only
occur in the waking state. The onset of these spells is
usually between ages 3 and 9 months, but they may
begin in the first month of life. The spells usually cease
within 2 weeks to 8 months of onset,10 but may persist
for 1 to 2 years.7 Both ictal and interictal EEGs are
normal, distinguishing this entity from infantile
spasms. Treatment is not required. Development and
neurologic
outcome are normal