The cases of non convulsive, complex, partial ailment are a cause of a confusional state. Such a case on an adult is here reported, and its clinical presentation was a unvarying forgetfulness together with elements of a frontal syndrome. The aetiology was most probably a viral meningo-encephalitis. Clinical semiology of these "EMPC" is variable, either made of partial, recurrent attacks, sometimes with automatisms, or made of a continuous, possibly fluctuating, confusional state. Attacks shown on the EEG are partial or generalized with a variable start, sometimes bilateral, even continuous or discontinuous. The onset is most often temporal or frontal. The cause is very rarely found out. The evolution is usually good, but extended deficiencies of memory are described, linked to the duration (more than 12 hours) of EMPC. Therefore, the treatment must be precocious using diazepam or phenytoin.