Periodic electroencephalographic compleses and subacute sclerosing panencephalitis. A case report and a survey of literature.

The authors report the case of a child with a presumable diagnosis of subacute sclerosing panencephalitis (SSPE). But pathological examination of the brain showed only a moderate neuronal loss in the cortical and subcortical grey matter. From this case and from the data in the literature it is concluded that the electroencephalogram in stage II of SSPE is characterized by the appearance of paroxysmal wave complexes which recur pseudo-periodically against a disorganized basic activity. The criteria for these complexes are not as strict and the periodicity is not as regular as formerly believed. Such a tracing is not pathognomonic of SSPE and may also occur-although rarely-in other brain diseases. The theory that the periodic discharges originate from a diffuse alteration of cortical and subcortical grey matter seems the most plausible.