Narcolepsy is characterized by excessive
sleepiness,
hypnagogic hallucinations, and
sleep paralysis, and can occur with or without
cataplexy. Here, we report two children with
narcolepsy presenting with
cataplexy mimicking epileptic
seizures as determined by long-term video-electroencephalography (EEG) and electromyography (EMG) monitoring. Case 1 was a 15-year-old girl presenting with recurrent episodes of "convulsions" and
loss of consciousness, who was referred to our hospital with a diagnosis of
epilepsy showing "convulsions" and "
complex partial seizures". The long-term video-polygraph showed a clonic attack lasting for 15 s, which corresponded to 1-2 Hz with interruption of mentalis EMG discharges lasting for 70-300 ms without any EEG changes.
Narcolepsy was suspected due to the attack induced by hearty laughs and the presence of sleep attacks, and confirmed by low
orexin levels in cerebrospinal fluid (CSF). Case 2 was an 11-year-old girl presenting with recurrent episodes of myoclonic attacks simultaneously with dropping objects immediately after hearty laughs, in addition to sleep attacks,
hypnagogic hallucinations, and
sleep paralysis. The long-term video-polygraph showed a subtle attack, characterized by dropping chopsticks from her hand, which corresponded to an interruption of ongoing deltoid EMG discharges lasting 140 ms without any EEG changes. A diagnosis of
narcolepsy was confirmed by the low
orexin levels in CSF. These cases demonstrate that children with
narcolepsy may have attacks of
cataplexy that resemble clonic or
myoclonic seizures.