BACKGROUND: Subacute sclerosing panencephalitis (SSPE) is a chronic central 
nervous (CNS) system infection caused by measles virus. Because changing 
immunization practices affect the epidemiology of measles and consequently SSPE, 
we examined the epidemiological data of our SSPE registry.
MATERIALS AND METHODS: Age of onset, age at onset of measles, duration of Latent 
period and immunization status were examined in cases recorded at the SSPE 
Registry Center in Turkey between 1975 and 1999.
RESULTS: Age of onset diminished from 13 years before 1994 to 7.6 years after 
1995; age at onset of measles declined from 29 months to 20 months and the 
Latent interval from 9.9 years to 5.9 years. Age at onset of measles and 
immunization status did not directly affect the duration of the Latent period.
CONCLUSION: Although its incidence has decreased in Turkey, SSPE has been seen 
at younger ages in recent years. This change cannot be attributed solely to 
younger age at onset of measles. Factors affecting the duration of the Latent 
period should be investigated further.