Our aim was to investigate the natural evolution of
cataplexy and polysomnographic features in untreated children with
narcolepsy with
cataplexy. To this end, clinical, polysomnographic, and
cataplexy-video assessments were performed at diagnosis (mean age of 10 ± 3 and disease duration of 1 ± 1 years) and after a median follow-up of 3 years from symptom onset (mean age of 12 ± 4 years) in 21 children with
narcolepsy with
cataplexy and
hypocretin 1 deficiency (tested in 19 subjects). Video assessment was also performed in two control groups matched for age and sex at first evaluation and follow-up and was blindly scored for presence of hypotonic (negative) and active movements. Patients' data at diagnosis and at follow-up were contrasted, compared with controls, and related with age and disease duration. At diagnosis children with
narcolepsy with
cataplexy showed an increase of sleep time during the 24 h; at follow-up sleep time and nocturnal sleep latency shortened, in the absence of other polysomnographic or clinical (including body mass index) changes. Hypotonic phenomena and selected facial movements decreased over time and, tested against disease duration and age, appeared as age-dependent. At onset, childhood
narcolepsy with
cataplexy is characterized by an abrupt increase of total sleep over the 24 h, generalized
hypotonia and motor overactivity. With time, the picture of
cataplexy evolves into classic presentation (i.e., brief
muscle weakness episodes triggered by emotions), whereas total sleep time across the 24 h decreases, returning to more age-appropriate levels.