Intra-individual variability across neurocognitive domains in chronic hepatitis C infection: elevated dispersion is associated with serostatus and unemployment risk

Abstract

Approximately one-third of persons infected with the hepatitis C virus (HCV) evidence mild cognitive impairment that is consistent with frontostriatal systems dysfunction, including cognitive dyscontrol, and impacts everyday functioning. The present study examined the effects of HCV on neurocognitive dispersion, or within-person variability in neurocognitive performance across domains, which may be a function of poor sustained cognitive control. High dispersion was also hypothesized to increase risk for unemployment. The study sample included 37 individuals with HCV infection (HCV+) and 45 demographically comparable uninfected comparison participants (HCV-). Dispersion was operationalized as an intra-individual standard deviation (ISD) calculated across the demographically adjusted T-scores of 13 standard neuropsychological tests. Multiple linear regression and logistic regression approaches were used to evaluate associations between dispersion and HCV serostatus and employment status, respectively. HCV serostatus was significantly associated with higher dispersion, independent of mean level of neurocognitive ability, psychiatric factors, and liver disease severity. Within the HCV+ group, higher dispersion was associated with an increased risk of unemployment among individuals with higher overall mean neurocognitive ability. Increased neurocognitive dispersion among HCV+ individuals may indicate vulnerability to cognitive dyscontrol expressed as poor regulation of performance across tasks. Higher dispersion may manifest as functional difficulties in daily life, particularly among neurocognitively normal HCV-infected persons, which speaks to the potential clinical value of considering intra-individual variability when evaluating risk for everyday function problems in this population.

Figure 1a

The box and whisker plots display Dispersion values for the unemployed versus employed groups within the HCV+ sub-sample with higher mean neuropsychological performance, revealing that all unemployed individuals evidenced higher levels of dispersion relative to a range of dispersion values in the employed group. (Note. The employment status for 1 participant was not available, and therefore that individual was excluded for this analysis.)

Figure 1b

Dispersion values for the unemployed versus employed groups within the HCV+ sub-sample with lower mean neuropsychological performance were not significantly different, as shown in the box and whisker plots.