[Atypical aspects of the electroencephalogram in subacute sclerosing panencephalitis]. / Aspects atypiques de l'électro-encéphalogramme au cours de la panencéphalite sclérosante subaiguë.

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.

[Electroencephalographic study of 40 patients with subacute sclerosing panencephalitis]. / Etude électro-encéphalographique de 40 malades atteints de panencéphalite sclérosante subaiguë.

Among viral diseases, subacute sclerosing panencephalitis is one of the most frequent in Iran (more than 300 cases in two neurological centers and for the last ten years). This paper is devoted to an electroencephalographic study of 40 patients: visual analysis of EEG rhythms (frequency, amplitude, lability, morphology), effects of activation methods, description of pathological EEG patterns (periodic paroxysmal complexes in 38 cases; slow or fast spikes, polyspikes and bifrontal or diffuse spikewaves in 9 cases; localized comitial abnormal patterns in 5 cases; bifrontal delta rhythm in 13 cases). From this description, we suggest an hypothesis of a diffuse localisation at the origin of periodic paroxysmal patterns: the periodic discharge of immune complexes from cerebral tissue into the cerebral circulation would constitute a synchronizing system which periodically modifies the blood-brain barrier permeability.