The incidence ranges from 0.25 to 0.60 per 1000 live births worldwide.[6]Cowan LD, Hudson LS. The epidemiology and natural history of infantile spasms. J Child Neurol. 1991 Oct;6(4):355-64.
http://www.ncbi.nlm.nih.gov/pubmed/1940138?tool=bestpractice.com
[7]Sidenvall R, Eeg-Olofsson O. Epidemiology of infantile spasms in Sweden. Epilepsia. 1995 Jun;36(6):572-4.
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[8]Riikonen R, Donner M. Incidence and aetiology of infantile spasms from 1960 to 1976: a population study in Finland. Dev Med Child Neurol. 1979 Jun;21(3):333-43.
http://www.ncbi.nlm.nih.gov/pubmed/467816?tool=bestpractice.com
[9]Kalra V, Gulati S, Pandey RM, et al. West syndrome and other infantile epileptic encephalopathies: Indian hospital experience. Brain Dev. 2002 Mar;24(2):130-9.
http://www.ncbi.nlm.nih.gov/pubmed/11891107?tool=bestpractice.com
Prevalence ranges from 0.15 to 0.2 per 1000 children under the age of 10 years.[10]Matsuo A, Matsuzaka T, Tsuru A, et al. Epidemiological and clinical studies of West syndrome in Nagasaki Prefecture, Japan. Brain Dev. 2001 Nov;23(7):575-9.
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[11]Cowan LD, Bodensteiner JB, Leviton A, et al. Prevalence of the epilepsies in children and adolescents. Epilepsia. 1989 Jan-Feb;30(1):94-106.
http://www.ncbi.nlm.nih.gov/pubmed/2463913?tool=bestpractice.com
There is a slight male preponderance, although no strong sex difference is observed.