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. 2018 Aug;24(4):506-513.
doi: 10.1007/s13365-018-0641-5. Epub 2018 Apr 25.

Does intra-individual neurocognitive variability relate to neuroinvasive disease and quality of life in West Nile Virus?

David P Sheppard  1 , Steven Paul Woods  2 , Rodrigo Hasbun  3 , Lucrecia Salazar  3 , Melissa S Nolan  4 , Kristy O Murray  4
Affiliations

Does intra-individual neurocognitive variability relate to neuroinvasive disease and quality of life in West Nile Virus?

David P Sheppard et al. J Neurovirol. 2018 Aug.

Abstract

West Nile Virus (WNV) can be a neuroinvasive pathogen that may produce persistent mild-to-moderate neurocognitive impairments in some infected persons. Intra-individual variability (IIV) is an index of a person's performance across a neuropsychological test or battery, which is an indicator of neurocognitive control and integrity of prefrontal systems. The present study examined possible associations of IIV to neurological health and well-being in WNV infection. Participants included 84 adults with a range of clinical WNV disease (31 West Nile Encephalitis, 16 West Nile Meningitis, 37 West Nile Fever) who completed the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). IIV was operationalized as covariance of variation (CoV), or the intra-individual standard deviation across 5 age-adjusted RBANS standard scores divided by the mean of standard scores. Participants were assessed for health-related quality of life (QoL) using the RAND 36-item short form health survey (SF-36). Analyses revealed that the West Nile Encephalitis group had higher neurocognitive CoV compared to the West Nile Fever group, and this difference was associated with a medium effect size (Cohen's d = .52). Mixed linear models controlling for estimated IQ, activities of daily living, depression, neuroinvasive disease groups, and fatigue showed that higher RBANS CoV was associated with lower physical, but not mental health QoL. In persons with WNV infection, there is a modest association between elevations in IIV and encephalitis, and even subtle disruptions in neuropsychological functioning show relationships with important self-reported functioning as measured by physical health quality of life. Future studies should examine whether IIV predicts long-term health outcomes (e.g., mortality) in individuals infected with WNV.

Keywords: Encephalitis; Intra-individual variability; Neuroinvasive disease; Neuropsychology; Quality of life; West Nile Virus.

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Conflict of interest statement

Conflict of Interest

The authors, David P. Sheppard, Steven Paul Woods, Rodrigo Hasbun, Lucrecia Salazar, Melissa S. Nolan, & Kristy O. Murray, declare that they have no conflict of interest.

Figures

Fig. 1
Fig. 1
Association between Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) intra-individual covariance and 36-Item Short Form Survey (SF-36) quality of life for (A) physical health and (B) mental health scales among 84 patients with West Nile virus infections
See this image and copyright information in PMC

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