Benign neonatal sleep myoclonus

common non-epileptic condition misdiagnosed as epileptic seizures and even as infantile spasms.

Onset is from the first day to 3 weeks of life with a peak at the seventh day

The myoclonus occurs during non-REM sleep in otherwise normal neonates

mainly affects the distal parts of the upper extremities with the lower limbs and axial muscles less often involved

the myoclonic jerks, synchronous or asynchronous, unilateral or bilateral, mild or violent, usually last for 10–20 s

occasionally they may occur in repetitive clusters of 2–3 s for 30 min or longer imitating myoclonic status epilepticus or a series of epileptic fits

the myoclonic jerks may get worse with gentle restraint

they abruptly stop when the child is awakened

sleep is not disturbed

not associated with apnoea, autonomic disturbances, automatisms, eye deviation, oral–buccal–lingual movements or crying.

normal neurology

unknown

does not appear to be familial

likely to be generated in the brain stem.

all investigations including sleep EEG are normal

neonatal seizures

hyperekplexia

Benign non-epileptic myoclonus of early infancy (benign non-epileptic infantile spasms)

excellent with the myoclonus commonly remitting by the age of 2–7 months.

no need for any treatment

minute doses of clonazepam before bed are often beneficial^[1]. Other anti-epileptic drugs are contraindicated.