[Viral meningoencephalitis: late development].

Two years ago, we performed a precocious evolutive EEG study of a specimen not selected from the virus ME to ECHO 4 burst (cepa prima) late 1972 to early 1973 (6). Some time between the appearance of the first symptoms and the 8 weeks following, alterations of cerebral electrogenesis became manifest in this study. These alterations disappeared or dimished in significance in the more tardy outlines: focalization tendency, tendency to change from "suffering" to "irritative" aspect. During this year, the test has been repeated on 82% of these patients, plus at the same time a minimum clinical survey. Until now, the results are the following. There are no clinical signs of the CNS in any case. School progress has not been affected, except moderately, for two patients. The EEG has become totally normal in more than 2/3 of the cases. Persistent EEG net signs of minimum "suffering" in three cases. There are "irritative" generalized signs in only 2 patients and "irritative" certified focal signs in 6 patients. Other EEG manifestations are of doubtful interpretation due to the age of the patients.