Cognitive reserve and neuropsychological functioning in patients infected with hepatitis C

Neurological and psychiatric effects of hepatitis C virus infection

Hepatitis C virus (HCV) infection is widespread and affects 71 million people worldwide. Although hepatic manifestations are the most frequent, ranging from chronic hepatitis to cirrhosis and hepatocellular carcinoma, it is also associated with several extrahepatic manifestations. Infected patients may present non-specific neurological symptoms, regardless of the presence of liver cirrhosis. Several pathogenetic mechanisms underlying neurological symptoms have been hypothesized: neuroinvasion, immune-mediated damage, neurotransmitter alterations and cryoglobulinemia. Alterations of the central nervous system include cerebral vasculopathy, acute or subacute encephalopathy and inflammatory disorders. HCV infection may be responsible for neuropathies, of which the most frequent form is symmetrical axonal sensory or sensory-motor polyneuropathy which causes loss of leg sensitivity and weakness. Up to 50% of patients with HCV infection may experience cognitive decline and psychological disorders, such as depression and fatigue. HCV associated neurocognitive disorder is independent of the presence of liver cirrhosis and affects different domains than in patients with hepatic encephalopathy. It can be studied using specific tests that mainly explore executive functions, verbal learning and verbal recall. These disorders significantly reduce the quality of life. The new antiviral therapies improve the extrahepatic symptoms of HCV infection and their success depends on the achievement of sustained virological response. However, the effect of therapy may differ depending on the type of organ involved; neurological symptoms can be irreversible if there is organic liver damage. The aim of this review is to provide a critical overview of physiopathological mechanisms, diagnostic and therapeutic strategies of the neurological and psychiatric effects of HCV infection.

Cognitive Reserve Mitigates Decline in Executive Functioning Following Hepatobiliary Diseases

Abstract. The cognitive reserve hypothesis postulates that lifelong cognitive stimulation establishes a buffer that is instrumental in maintaining cognitive health. To examine this conceptual proposition in detail, we applied a novel, more general conceptual view that included recent models of vulnerability and examined whether the longitudinal association between hepatobiliary diseases and later decline in executive functioning across 6 years varied by cognitive reserve. For this purpose, we investigated longitudinal data from 897 older individuals ( M = 74.33 years) tested using the Trail Making Test (TMT) in two waves 6 years apart. Individuals reported information on key commonly used indicators of lifelong cognitive reserve build-up (i.e., education, work, and participation in leisure activity) and hepatobiliary diseases. The results revealed a significant interaction of hepatobiliary diseases with participation in leisure activity on latent change in executive functioning. Specifically, only in individuals with little (but not greater) participation in leisure activity did hepatobiliary diseases significantly predict a steeper decline in executive functioning over 6 years (i.e., increases in TMT finishing time). In conclusion, the unfavorable aftereffects of hepatobiliary diseases on a later decline in executive functioning seem to be mitigated in individuals who have built up greater cognitive reserve via participation in leisure activity during their life.

Cognitive impairments in HCV infection: From pathogenesis to neuroimaging

Extrahepatic manifestations of hepatitis C virus (HCV) infection, in particular cognitive impairments, can be present in the absence of clinical liver dysfunction. Executive memory, attention, and concentration are cognitive domains that are most frequently affected. Microstructural and functional changes in cortical gray matter and basal ganglia associate these neuropsychiatric changes in early HCV infection. No study has covered the relationship between imaging features of HCV-related cognitive impairment and HCV pathology. Herein we summarize evidence suggesting a direct pathology of HCV in microglia, astrocytes, and microvascular endothelial cells, and a neuroinflammatory response in HCV-related cognitive decline. Lipoproteins and their receptors mediate HCV infectivity in the central nervous system and confer susceptibility to HCV-related cognitive decline. Magnetic resonance spectroscopy has revealed changes compatible with reactive gliosis and microglial activation in basal ganglia, frontal and occipital white matter, in the absence of cirrhosis or hepatic encephalopathy. Similarly, diffusion imaging shows evidence of structural disintegrity in the axonal fibers of white matter tracts associated with temporal and frontal cortices. We also discuss the cognitive benefits and side-effects of the two most popular therapeutic protocols interferon-based therapy and interferon-free therapy using direct acting anti-virals. Evidences support a network-based pattern of disruption in functional connectivity in HCV patients and a common neuronal substrate for HCV-related and interferon-therapy-associated cognitive decline. These evidences might help identify patients who benefit from either interferon-based or interferon-free treatment regimen.

Cognitive resilience in clinical and preclinical Alzheimer's disease: the Association of Amyloid and Tau Burden on cognitive performance

We explored the cross-sectional relationships between β-amyloid (Aβ) and inferior temporal tau deposition (IFT Tau) on cognitive performance and whether cognitive reserve (CR) modifies these associations. We studied 156 participants classified into groups of clinically normal (CN = 133), mild cognitive impairment (MCI = 17) and Alzheimer disease (AD = 6) dementia. AMNART IQ served as a proxy of CR and cognitive performance was assessed using the MMSE. In separate linear regression models predicting MMSE, we examined the interactions of CR x global Aβ and CR x IFT tau across all participants and within the CN group alone. In the whole sample, the interaction between CR and IFT tau was significant (p < 0.003), such that higher CR participants with elevated IFT tau had better MMSE scores compared with low CR participants with similar levels of IFT tau. The interaction between CR and Aβ status did not reach significance (p = 0.093). In CN only, no cross-sectional interactions among CR, Aβ, and IFT tau were observed on MMSE. These findings imply that CR may be protective against early AD processes and enable some individuals to remain cognitively stable despite elevated tau and Aβ burden.

Hepatitis C virus infection, and neurological and psychiatric disorders - A review

An association between hepatitis C virus infection and neuropsychiatric symptoms has been proposed for some years. A variety of studies have been undertaken to assess the nature and severity of these symptoms, which range from fatigue and depression to defects in attention and verbal reasoning. There is evidence of mild neurocognitive impairment in some patients with HCV infection, which is not fully attributable to liver dysfunction or psychosocial factors. Further evidence of a biological cerebral effect has arisen from studies using magnetic resonance spectroscopy; metabolic abnormalities correlate with cognitive dysfunction and resemble the patterns of neuroinflammation that have been described in HIV infection. Recent research has suggested that, in common with HIV infection, HCV may cross the blood brain barrier leading to neuroinflammation. Brain microvascular endothelial cells, astrocytes and microglia may be minor replication sites for HCV. Importantly, patient reported outcomes improve following successful antiviral therapy. Further research is required to elucidate the molecular basis for HCV entry and replication in the brain, and to clarify implications and recommendations for treatment.

Impact of Education on Memory Deficits in Subclinical Depression

Elevated depressive symptoms are associated with cognitive deficits, while higher education protects against cognitive decline. This study was conducted to test if education level moderates the relationship between depressive symptoms and cognitive function. Seventy-three healthy, dementia-free adults aged 18-81 completed neuropsychological tests, as well as depression and anxiety questionnaires. Controlling for age, sex, and state anxiety, we found a significant interaction of depressive symptoms and education for immediate and delayed verbal memory, such that those with a higher education level performed well regardless of depressive symptomatology, whereas those with lower education and high depressive symptoms had worse performance. No effects were found for executive functioning or processing speed. Results suggest that education protects against verbal memory deficits in individuals with elevated depressive symptoms. Further research on cognitive reserve in depression-related cognitive deficits and decline is needed to understand the mechanisms behind this phenomenon.

Processes to manage analyses and publications in a phase III multicenter randomized clinical trial

Background

The timely publication of findings in peer-reviewed journals is a primary goal of clinical research. In clinical trials, the processes leading to publication can be complex from choice and prioritization of analytic topics through to journal submission and revisions. As little literature exists on the publication process for multicenter trials, we describe the development, implementation, and effectiveness of such a process in a multicenter trial.

Methods

The Hepatitis C Antiviral Long-Term Treatment against Cirrhosis (HALT-C) trial included a data coordinating center (DCC) and clinical centers that recruited and followed more than 1,000 patients. Publication guidelines were approved by the steering committee, and the publications committee monitored the publication process from selection of topics to publication.

Results

A total of 73 manuscripts were published in 23 peer-reviewed journals. When manuscripts were closely tracked, the median time for analyses and drafting of manuscripts was 8 months. The median time for data analyses was 5 months and the median time for manuscript drafting was 3 months. The median time for publications committee review, submission, and journal acceptance was 7 months, and the median time from analytic start to journal acceptance was 18 months.

Conclusions

Effective publication guidelines must be comprehensive, implemented early in a trial, and require active management by study investigators. Successful collaboration, such as in the HALT-C trial, can serve as a model for others involved in multidisciplinary and multicenter research programs.

Trial registration

The HALT-C Trial was registered with clinicaltrials.gov (NCT00006164).

Protective effects of higher cognitive reserve for neuropsychological and daily functioning among individuals infected with hepatitis C

Higher levels of cognitive reserve (CR) can be protective against the neuropsychological manifestation of neural injury across a variety of clinical disorders. However, the role of CR in the expression of neurocognitive deficits among persons infected with the hepatitis C virus (HCV) is not well understood. Thirty-nine HCV-infected participants were classified as having either high (n = 19) or low (n = 20) CR based on educational attainment, oral word reading, and IQ scores. A sample of 40 demographically comparable healthy adults (HA) was also included. All participants completed the Neuropsychological Assessment Battery, Delis-Kaplan Executive Function System, and Behavioral Rating Inventory of Executive Function, Adult Version (BRIEF-A). Linear regression analyses, controlling for gender, depression, and lifetime substance use disorders, found significant effects of HCV/CR group on verbal fluency, executive functions, and daily functioning T scores, but not in learning or the BRIEF-A. Pairwise comparisons revealed that the HCV group with low CR performed significantly below the HCV high CR and HA cohorts, who did not differ from one another. Findings indicate that higher levels of CR may be a protective factor in the neurocognitive and real-world manifestation of neural injury commonly associated with HCV infection.

Comparison of cognitive performance in HIV or HCV mono-infected and HIV-HCV co-infected patients

PURPOSE

Our aim was to explore the interplay between human immunodeficiency virus (HIV) and hepatitis C virus (HCV) infections in the expression of cognitive disorders.

METHODS

We performed a multi-centre cross-sectional study, enrolling three groups of asymptomatic outpatients matched for age and education: (1) HIV mono-infected; (2) HCV mono-infected; (3) HIV-HCV co-infected. All subjects were subjected to the Zung depression scale and a comprehensive neuropsychological battery.

RESULTS

A total of 50 patients for each group were enrolled. Patients in the three groups did not significantly differ in the main common demographic and clinical characteristics, except for a lower proportion of past injecting drug use (IDU) in group 1 (4 %) in comparison to groups 2 (38 %, p < 0.001) and 3 (78 %, p < 0.001), a longer duration of HIV infection in group 3 in comparison to group 1 (p < 0.001) and a longer duration of HCV infection in group 3 in comparison to group 2 (p = 0.028). Overall, 39.3 % of patients showed minor cognitive impairment, with a higher proportion in group 3 (54 %) when compared to groups 1 (28 %, p = 0.015) or 2 (36 %, p = 0.108). Patients in group 3 [odds ratio (OR) 3.35, p = 0.038 when compared to group 1] and those with higher depression scores (OR 1.05, p = 0.017) showed an increased risk of cognitive impairment after adjusting for education and past injection drug use. In particular, group 3 showed worse performance in psychomotor speed tasks when compared to group 1 (p = 0.033).

CONCLUSIONS

A worse cognitive performance in HIV-HCV co-infected patients was observed, suggesting an additive role of the two viruses in the pathogenesis of cognitive disorders.

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

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.

Influence of education on subcortical hyperintensities and global cognitive status in vascular dementia

Subcortical hyperintensities (SH) on neuroimaging are a prominent feature of vascular dementia (VaD) and SH severity correlates with cognitive impairment in this population. Previous studies demonstrated that SH burden accounts for a degree of the cognitive burden among VaD patients, although it remains unclear if individual factors such as cognitive reserve influence cognitive status in VaD. To address this issue, we examined 36 individuals diagnosed with probable VaD (age = 77.56; education = 12). All individuals underwent MMSE evaluations and MRI brain scans. We predicted that individuals with higher educational attainment would exhibit less cognitive difficulty despite similar levels of SH volume, compared to individuals with less educational attainment. A regression analysis revealed that greater SH volume was associated with lower scores on the MMSE. Additionally, education moderated the relationship between SH volume and MMSE score, demonstrating that individuals with higher education had higher scores on the MMSE despite similar degrees of SH burden. These results suggest that educational attainment buffers the deleterious effects of SH burden on cognitive status among VaD patients.

Cognitive performance and mood in patients on the waiting list for liver transplantation and their relation to the model for end-stage liver disease

OBJECTIVE: To investigate the links between depression and cognitive functioning in patients with Hepatitis C and other chronic liver diseases with and without the use of alcohol on the waiting list for liver transplantation and their associations with the MELD classification. METHOD: 40 patients were evaluated on a waiting list for liver transplant by a battery of neuropsychological tests, depression scales and interview at the Liver Transplant Service, of the Hospital das Clínicas University of São Paulo Medical School. RESULTS: After splitting the sample according to the education, the results showed statistical significance in the comparisons between groups of MELD > 15 and <15 in the following functions: estimated IQ, visual-spatial delayed recall and recognition as part of episodic memory and short term memory. CONCLUSION: These findings, usually found in hepatic encephalopathy, corroborated with the literature and emphasized the need to investigate in more detail the cognitive functions of these patients in order to facilitate the adoption of different conducts.

The cognitive effects of hepatitis C in the presence and absence of a history of substance use disorder

The aim of the study was to determine whether infection with the hepatitis C virus (HCV) is associated with cognitive impairment beyond the effects of prevalent comorbidities and a history of substance use disorder (SUD). Adult veterans were recruited from the Portland Veterans Affairs Medical Center into three groups: (1) HCV+/SUD+ (n = 39), (2) HCV+/SUD- (n = 24), and (3) HCV-/SUD- (n = 56). SUD+ participants were in remission for > or =90 days, while SUD- participants had no history of SUD. Groups did not significantly differ in terms of rates of psychiatric or medical comorbidities. Procedures included clinical interviews, medical record reviews, and neuropsychological testing. Significant group differences were found in the domains of Verbal Memory, Auditory Attention, Speeded Visual Information Processing, and Reasoning/Mental Flexibility (p <or = .05). Post hoc comparisons indicated that HCV+/SUD- patients performed significantly worse than HCV-/SUD- controls on tests measuring verbal learning, auditory attention, and reasoning/mental flexibility, but only HCV+/SUD+ patients did worse than HCV-/SUD- controls on tests of speeded visual information processing. Results indicate that chronic HCV is associated with cognitive impairment in the absence of a history of SUD. The most robust deficits appear to be in verbal learning and reasoning/mental flexibility. (JINS, 2009, 15, 69-82.).

Impairments in fine-motor coordination and speed of information processing predict declines in everyday functioning in hepatitis C infection

Research increasingly supports the neurovirulence of chronic infection with the hepatitis C virus (HCV). For example, HCV infection has been associated with neuropsychological impairment in several ability areas, including psychomotor skills. This study aimed to examine whether HCV-associated neuropsychological impairment is predictive of declines in the independent performance of physical (PADLs) and instrumental (IADLs) activities of daily living. A total of 106 volunteers with HCV infection completed a comprehensive neuropsychological, medical, and psychiatric research evaluation. As compared to 30 HCV-seronegative comparison participants, the HCV-infected group reported significantly greater declines in both PADLs and IADLs. Within the HCV cohort, individuals with impaired speed of information processing reported significantly greater IADL declines, whereas impaired fine-motor coordination was associated with declines in both IADLs and PADLs. In a series of regression analyses, impaired speed of information processing and depressive symptoms (as measured by the Beck Depression Inventory) were the only independent predictors of IADL declines, whereas general affective distress (as measured by the Profile of Mood States), sex, and fine-motor coordination impairment were predictive of declines in PADLs. Although the clinical assessment of HCV typically emphasizes both affective (e.g., depression) and physical factors, findings from the present study suggest that cognitive impairment is an important contributor to everyday functioning in persons living with HCV infection and therefore warrants consideration in clinical and research evaluations.