This prospective study evaluated the electroencephalographic (EEG) dia
gnostic and prognostic value in childhood HN infection. It was carried
out on 125 subjects and included all Piemonte's seropositive children
. The EEG was repeated every three months during the first 15 months o
f life, and then, at least, annually in the P1 and P2 group. Data of g
roup P2 was compared bindly to that of the seroconverted control group
of the same age and risk. EEG results were normal in PO, P1 and contr
ol patients. In group P2, EEG was abnormal in 35.5% of subjects, of th
ese 54.6% developed an encephalopathy with a delay of 2.5 months to 2
years 11 months. EEG is therefore useful to evaluate early CNS damage
and to identify onset features and evolution of encephalopathy in P2 p
atients.