[Atypical aspects of the electroencephalogram in subacute sclerosing panencephalitis]

Diffuse paroxysmal and periodic discharges in subacute sclerosing panencephalitis (SSPE), have a specific temporo-spatial character in about 90% of cases. A random selection of 100 among 358 cases was performed in this study and the following results were obtained. Twelve cases showed no initial diffuse paroxysmal and periodic discharges but an atypical pattern consisting in: 1) unilateral periodic activity (three cases); 2) bifrontal rhythmic delta activity (two cases); 3) epileptic discharges, one of which was absence (four cases); focal delta activity (one case); 5) normal EEG (two cases). One apparently benign case is also reported.