ELECTROENCEPHALOGRAPHIC STUDY OF PATIENTS WITH ACUTE ASEPTIC MENINGITIS

Abstract

One hundred fifty-eight patients with aseptic meningitis were studied electroencephalographically during the acute phase of the illness. Slow activity was more common among children below 10 years of age (44%) than among adults (10%). With the exception of two cases, the electroencephalogram either normalized quickly after recovery from the acute illness or returned to what was believed to be the pre-illness abnormality. In one of the two persons who developed persistent abnormalities, slow activity continued long after the acute phase of the illness was over, and in the other the slow activity was complicated by the development of 6-per-second positive spike discharges. See figure in the PDF.file See table in the PDF.file See figure in the PDF.file Slow activity in the acute phase of the illness was more common when the infection was caused by ECHO virus (26%) than when it was caused by Coxsackie (14%). The sporadic cases of aseptic meningitis that were usually caused by a nonidentifiable agent were associated with a slightly higher electroencephalographic morbidity than the cases occurring in epidemics of known etiology. From the electroencephalographic as well as from the clinical point of view, aseptic meningitis is relatively benign. It is associated with less disorder than measles, which produces slow activity in 50% of cases. About as many patients developed slow activity during the acute phase of aseptic meningitis (33%) as mumps, but like mumps (and various other virus infections) aseptic meningitis can be followed by persistent electroencephalographic abnormalities. Because the viruses that cause aseptic meningitis may produce lasting brain disorder, they cannot be considered innocuous or inconsequential.