Cognitive Impairment After Acute Encephalitis: An ERP Study

ABSTRACT

Cognitive deficits are often observed during the acute stage of encephalitis. It is presumed, that they persist and influence the long-term outcome, but data are very limited. Forty-seven patients with a definite or highly probable diagnosis of acute encephalitis were identified through retrospective analysis and prospectively followed up 6–84 months after the acute illness. P3 was carried out by oddball auditory paradigm, and P3 latency was measured as a marker of cognitive impairment. Healthy people, who matched the patients in age, were used as controls (n = 39). Statistical group analysis revealed no significant difference of the P3 latency between the patient and the control group. However a subgroup analysis showed significant longer P3 latencies in patients with a more unfavorable functional outcome at the time of follow-up. Patients with Herpes simplex virus (HSV) encephalitis had also more often abnormal P3 values compared to other etiologic subgroups, potentially indicating a higher percentage of patients with unfavorable cognitive outcome in this subgroup.

KEYWORDS: :

• acute encephalitis
• cognitive outcome
• event-related potential
• P3