Narcolepsy 373
b. In children or in individuals within 6 months of onset, spontaneous grimaces or
jaw-opening episodes with tongue thrusting or a global hypotonia, without any
obvious emotional triggers.
2. Hypocretin deficiency, as measured usi ng cerebrospinal fluid (CSF) hypocretin-1
immunoreactivity values (less than or equal to one-third of values obtained in
healthy subjects tested using the same assay, or less than or equal to 110 pg/mL).
Low CSF levels of hypocretin-1 must not be observed in the context of acute brain
injury, inflammation, or infection.
3. Nocturnal sleep polysomnography showing rapid eye movement (REM) sleep la-
tency less than or equal to 15 minutes, or a multiple sleep latency test showing a
mean sleep latency less than or equal to 8 minutes and two or more sleep-onset
REM periods.
Specify whether:
347.00 (G47.419) Na rcolepsy without cataplexy but  with hypocretin deficiency:  Cri-
terion B requirements of low CSF hypocretin-1 levels and positive polysomnography/
multiple sleep latency test are met, but no cataplexy is present (Criterion B1 not met).
347.01 (G47.411) Narcolepsy with cataplexy but without hypocretin deficiency:
In this rare subtype (less than 5% of narcolepsy cases), Criterion B requirements of
cataplexy and positive polysomnography/multiple sleep latency test are met, but CSF
hypocretin-1 levels are normal (Criterion B2 not met).
347.00 (G47.419) Autosomal dominant cereb ellar ataxia, deafness, and narco-