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Biomedical subjects

Kevin R Robertson

Publications and source records attributed to Kevin R Robertson.

9 recordsLinked to original sources
PubMed2006

Neurocognitive functioning and HAART in HIV and hepatitis C virus co-infection.

OBJECTIVES: This study examined the effects of HAART on neurocognitive functioning in persons with hepatitis C virus (HCV) and HIV co-infection. DESIGN: A prospective study examining neurocognitive performance before and after HAART initiation. METHOD: Participant groups included a mono-infected group (45 HIV+/HCV- participants) and a co-infected group (20 HIV+/HCV+ participants). A neuropsychological battery (attention/concentration, psychomotor speed, executive functioning, verbal memory, visual memory, fine motor, and gross motor functioning) was used to evaluate all participants. After 6 months of HAART, 31 HIV+ mono-infected and 13 HCV+/HIV+ co-infected participants were reevaluated. RESULTS: Neurocognitive functioning by domain revealed significantly worse performance in the co-infected group when compared to the monoinfected group on domains of visual memory and fine motor functioning. Assessment of neurocognitive functioning after antiretroviral therapy revealed that the co-infected group was no longer performing worse than the monoinfected group. CONCLUSIONS: The findings of the current study suggest that persons with HCV+/HIV+ co-infection may have greater neurocognitive declines than persons with HIV infection alone. HCV+/HIV+ co-infection may accelerate the progression of HIV related neurocognitive decline.

Adult↗
PubMed2006

Better quality of life with neuropsychological improvement on HAART.

BACKGROUND: Successful highly active antiretroviral therapy (HAART) regimens have resulted in substantial improvements in the systemic health of HIV infected persons and increased survival times. Despite increased systemic health, the prevalence of minor HIV-associated cognitive impairment appears to be rising with increased longevity, and it remains to be seen what functional outcomes will result from these improvements. Cognitive impairment can dramatically impact functional ability and day-to-day productivity. We assessed the relationship of quality of life (QOL) and neuropsychological functioning with successful HAART treatment. METHODS: In a prospective longitudinal study, subjects were evaluated before instituting HAART (naïve) or before changing HAART regimens because current therapy failed to maintain suppression of plasma viral load (treatment failure). Subjects underwent detailed neuropsychological and neurological examinations, as well as psychological evaluation sensitive to possible confounds. Re-evaluation was performed six months after institution of the new HAART regimen and/or if plasma viral load indicated treatment failure. At each evaluation, subjects underwent ultrasensitive HIV RNA quantitative evaluation in both plasma and cerebrospinal fluid. RESULTS: HAART successes performed better than failures on measures exploring speed of mental processing (p < .02). HAART failure was significantly associated with increased self-reports of physical health complaints (p < .01) and substance abuse (p < .01). An interesting trend emerged, in which HAART failures endorsed greater levels of psychological and cognitive complaints (p = .06). Analysis between neuropsychological measures and QOL scores revealed significant correlation between QOL Total and processing speed (p < .05), as well as flexibility (p < .05). CONCLUSION: Our study investigated the relationship between HIV-associated neurocognitive impairment and quality of life. HAART failures experienced slower psychomotor processing, and had increased self-reports of physical health complaints and substance abuse. Contrariwise, HAART successes experienced improved mental processing, demonstrating the impact of successful treatment on functioning. With increasing life expectancy for those who are HIV seropositive, it is important to measure cognitive functioning in relation to the actual QOL these individuals report. The study results have implications for the optimal management of HIV-infected persons. Specific support or intervention may be beneficial for those who have failed HAART in order to decrease substance abuse and increase overall physical health.

Adult↗
PubMed2006

Timed Gait test: normative data for the assessment of the AIDS dementia complex.

The Timed Gait test is a standardized procedure assessing motor dysfunction of lower extremities and gait abnormalities associated with AIDS dementia complex. Heretofore, interpretations of Timed Gait results have been hampered by the lack of normative data. We provide results on this test derived from 1,549 subjects (HIV-seronegatives (HIV-) and seropositives (HIV+) classified according to ADC stage). Timed Gait was found to be a useful screening and assessment tool for evaluating ADC and correlated with clinical ADC staging as well as more extensive structured neurological and neuropsychological evaluations. Analysis of covariance results (with age and education as covariates) revealed symptomatic HIV+(SX) and AIDS groups having significantly slower Timed Gait scores than those in the HIV- and asymptomatic HIV+(ASX) groups. The SX group obtained significantly slower timed gait scores than those in the AIDS group. There was a significant increase in Timed Gait scores with each increase in dementia staging with the HIV- subjects having the fastest mean Timed Gait scores and the HIV+ dementia stage 2+ having the slowest. These normative data should prove useful in both recognition of ADC and treatment response. Given its minimal training requirements, the Timed Gait would have utility in resource limited settings.

AIDS Dementia Complex↗
PubMed2005

Cerebrospinal fluid from human immunodeficiency virus--infected individuals facilitates neurotoxicity by suppressing intracellular calcium recovery.

Neurologic decline associated with penetration of human immunodeficiency virus type 1(HIV-1) into the central nervous system is thought to be due, in large part, to inflammation and local secretion of neurotoxic substances. To examine the cellular processes that mediate neurotoxicity in vivo, the authors valuated the ability of neurons to maintain intracellular calcium homeostasis in the presence of toxic cerebrospinal fluid (CSF) (CSF(tox)) collected from a subset of HIV-infected individuals. Exposure of rat neural cultures to CSF(tox) resulted in a gradual increase in intracellular calcium in neurons (+63%), microglia (+251%), and astrocytes (+52%). Pretreatment of neural cultures with CSF(tox) resulted in an exaggerated calcium response to a brief pulse of glutamate and a > 90% suppression of the rate of recovery of intracellular calcium. Attempts to model the deficit using inhibitors of calcium transport across endoplasmic reticulum, mitochondrial, or plasma membrane indicated that blockade of the plasma membrane sodium/calcium exchanger was best able to reproduce the deficits seen during exposure to CSF(tox). Because the inability of cells to maintain calcium homeostasis would lead to exaggerated responses from a wide variety of stimuli, therapeutics designed to facilitate calcium transport from the cell may provide more comprehensive and effective intervention than strategies targeted to specific receptor pathways.

Adult↗
PubMed2004

No gender differences in the progression of nervous system disease in HIV infection.

The past decade has seen a marked increase in the number of HIV-infected women in the United States. There has been recent concern that HIV disease in general may progress more rapidly in women than men, and some studies, primarily retrospective reviews, have suggested higher rates of neurologic disease among females. The objective of this study was to assess gender differences in HIV-related central and peripheral nervous system disease over time. Participants were enrolled in a longitudinal cohort study at the University of North Carolina and had annual follow-up evaluations. At baseline, 42 HIV-negative females, 52 HIV-positive females, and 52 HIV-positive males were compared for age, education, mode of infection, absolute CD4 cell count, and plasma/cerebrospinal fluid HIV RNA load. Subjects were evaluated by standardized clinical neurologic, neuropsychological, and laboratory examinations every year. The results indicated that both HIV-positive males and HIV-positive females had poorer neurologic functioning than the control group. However, there was no evidence from the parameters measured that the rate of decline differed between HIV-positive males and HIV-positive females.

AIDS Dementia Complex↗
PubMed2004

Highly active antiretroviral therapy improves neurocognitive functioning.

Although the effects of highly active antiretroviral therapy (HAART) have resulted in substantial improvements in the systemic health of patients with HIV infection, concerns remain that these medications, which cross the blood-brain barrier poorly, may have a less beneficial effect on nervous system function. This raises the possibility that there may be a progressive long-term decline in neurologic function in patients with adequate systemic response. In a prospective longitudinal study, subjects were evaluated immediately before instituting HAART. Forty-eight subjects underwent ultrasensitive HIV RNA quantitative evaluation of both plasma and cerebrospinal fluid as well as neurologic and neuropsychological examinations. They were reevaluated 6 months after treatment initiation while receiving stable HAART. Both plasma and cerebrospinal fluid viral levels significantly declined after treatment. There was significant improvement in neurologic and neuropsychological functioning after HAART. These results indicate that despite the poor central nervous system penetration of most of these agents, there is satisfactory short-term improvement in both central nervous system viral burden and nervous system function with HAART. However, because treatment failure is increasingly likely over time, continued longitudinal evaluation of this group of subjects is required.

AIDS Dementia Complex↗
PubMed2004

Neuroimaging in human immunodeficiency virus infection.

Human immunodeficiency virus (HIV) is associated with central nervous system (CNS) changes that may affect cerebral blood flow (CBF), metabolism, structure, and diffusion. Each of the available neuroimaging techniques offers unique insight into the neural mechanisms underlying HIV, as well as a potential means of monitoring disease progression and treatment response. The purpose of the article is to provide a review of experimental studies evaluating changes related to HIV with imaging techniques, including single-photon emission computed tomography (SPECT), positron emission tomography (PET), volumetric magnetic resonance imaging (MRI), functional MRI (fMRI), magnetic resonance spectroscopy (MRS), diffusion tensor imaging (DTI), and perfusion MRI (pMRI).

AIDS Dementia Complex↗
PubMed2002

The Minnesota Multiphasic Personality Inventory-2 across the human immunodeficiency virus spectrum.

The Minnesota Multiphasic Personality Inventory-2 (MMPI-2) was used to assess individuals' patterns of psychological symptoms across the spectrum of HIV illness. Two hundred and twenty-five participants in the present sample were administered the MMPI-2, 61 were HIV-seronegative controls, 61 were asymptomatic, 36 were symptomatic, and 67 met criteria for AIDS. Symptomatic HIV-seropositive patients scored higher on the Hypochondriasis, Conversion-Hysteria, and Depression Scales. These differences appeared to be largely due to an increase in somatic complaints rather than an increase in other depressive symptoms. Group differences did not appear to be due to HIV-associated neuropsychological dysfunction. Interpretive strategies for the MMPI-2 and treatment considerations are discussed.

Analysis of Variance↗