[Subacute sclerosing panencephalitis (SSPE); clinical and epidemiological observations of 56 cases studied from 1956 to 1978].

Epidemiological observations on 56 cases of SSPE studied at the Institute of Virology of the University of Milan between 1956 and 1978 and the clinical features of 47 of them, all hospitalized at the Neurologic Institute "C. Besta" of Milan, are reported. The criteria adopted for the diagnosis of the cases, the symptoms at onset and the signs of involvement of CNS eventually present before SSPE and illustrated. Age at onset of SSPE was between 2 and 25 years, average 9,4 years; survival varied from 2 months to 2 years in 20 cases, from 25 months to 7 years in 9 patients while 3 children are still living after 9--11 years. In 1 case a substantial long remission of clinical symptomatology has been observed. As to the distribution of cases, both in the Lombardy region and in the Milan province a low incidence has been noted in the first 10 years, followed by a first increase in the successive decade (1965-1974) and by an abrupt increase from 1975 on. In the Milan province, to be pointed out a lack of cases in the period 1958-1962 and in some of the subsequent years, while since 1971 one or more cases have been observed each year with a maximum of 4-5 subjects from 1975 on. This last figure for an average resident population of 4 millions, averages an SSPE yearly rate of 1-1,15 cases/10(6) inhabitants. Similar to that of other reports are the higher prevalence among males than among females (ratio M/F = 1,4 : 1), and an average distance of 5,6 years from measles. It is also evident an association of SSPE with measles at early age although recent patients seem to have had their infection later in life.