Neurocognitive and functional outcomes in persons recovering from West Nile virus illness.

Long-term neurocognitive and functional impairments following West Nile virus (WNV) disease are poorly understood. We assessed quality-of-life indices and neurocognitive performance in a cohort of 54 persons recovering from one of three WNV disease syndromes (fever [WNF], meningitis [WNM], or encephalitis [WNE]) approximately 1.5 years following acute illness. We compared findings between the three syndromic groups; the study cohort and a demographically similar group of 55 controls from a study of chronic fatigue syndrome (CFS); and the study cohort and a 'normative' control population based on cognitive test data. Persistent symptoms, diminished quality of life, and functional impairment were reported by 50% of WNF patients, and 75% each of WNM and WNE patients. Overall, objective neurocognitive performance did not differ significantly between the three syndromic groups, or between the study cohort and the CFS controls or the normative controls. In some neurocognitive subtests, the study cohort scored below the 15th percentile when compared with normative control data. Most persons who returned to independent living following hospitalization for WNV illness had persistent subjective complaints, but had normal cognitive function. However, a minority displayed subtle neurocognitive deficits more than 18 months following acute disease.