COGNITIVE RECOVERY INSTEAD OF DECLINE AFTER ACUTE ENCEPHALITIS - A PROSPECTIVE FOLLOW-UP-STUDY

Objective-Follow up of cognitive sequelae of acute encephalitis and es timation of the frequency of persisting dementia. Methods-Out of a ser ies of 45 consecutive patients with acute encephalitis prospectively s tudied in 1990-95, 40 were screened for difficulty in everyday life us ing the Blessed dementia scale (BDS) 3.7 (1.4), mean (SD), years after onset. Eight patients had had herpes simplex encephalitis (HSVE), 16 some other identified aetiology, and in 21 the aetiology was unknown. All, except two patients with a non-herpetic encephalitis, were treate d with acyclovir. All patients with disability in BDS (12/40), were in vited to a neuropsychological reassessment, and the results of this as sessment were compared with those of a similar assessment done after t he acute stage. At follow up one patient could not complete the tests due to intractable epilepsy. Results-In six of 11 cases the symptoms c ausing disability were mainly psychiatric. Five patients (two with HSV E) had a pronounced memory impairment together with other cognitive de ficits, indicating dementia (frequency of 12.8%). In eight of the 11 t estable cases cognitive performance had improved over the years, in tw o cases a decline was found and one patient with severe deficits showe d no change. Intractable epilepsy was found in four of 12 cases. Concl usion-Cognitive decline had taken place already at the acute stage, an d further deterioration was uncommon. Considerable improvement occurre d in most patients during follow up. Also in patients with HSVE treate d with acyclovir the cognitive recovery was substantial and of a magni tude not expected based on previous Literature. Intractable epilepsy c ontributed to the cognitive deterioration in some cases. Affective dis orders also had a surprisingly important role for the long term outcom e.