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Biomedical subjects

Eileen M Martin

Publications and source records attributed to Eileen M Martin.

13 recordsLinked to original sources
PubMed2006

Impaired decision-making in psychopathic heroin addicts.

Substance-dependent individuals (SDIs) often show neurocognitive deficits in decision-making, such that their choices are biased toward the greatest immediate reward rather than the optimal future outcome. However, studies of SDIs are often hampered by two significant methodological challenges: polysubstance dependence and comorbid conditions, which are independently associated with neurocognitive impairments. We addressed these methodological challenges by testing heroin addicts in Bulgaria, where heroin addiction is highly prevalent but polysubstance dependence is rare. The goal of the current study was to evaluate the potential contribution of psychopathy to decision-making processes among this group of Bulgarian heroin addicts. We tested 78 male currently abstaining heroin addicts, classified as psychopathic or non-psychopathic using the Hare Psychopathy Checklist, Revised (PCL-R). Psychopathic heroin addicts showed notable deficits in decision-making in that they made significantly more disadvantageous decisions relative to non-psychopathic heroin addicts. Results indicate that the presence of psychopathy may exacerbate decision-making deficits in heroin addicts.

Adolescent↗
PubMed2006

Demographically adjusted normative standards for new indices of performance on the Paced Auditory Serial Addition Task (PASAT).

The Paced Auditory Serial Addition Task (PASAT) is a complex cognitive test sensitive to neuropsychological disorders. Its traditional Total Correct score seemingly reflects multiple cognitive abilities, including attention, working memory, and processing speed. Snyder, Aniskiewicz, and Snyder (1993) modified scoring guidelines for the PASAT to give credit only for "dyads." This method emphasizes working memory operations and has been found superior to Total Correct scores at detecting cognitive impairments in several investigations. To date, normative standards are not available for the "dyad" scoring method, thus limiting its utility in clinical and research settings. The current investigation provides demographically adjusted normative data based on a sample of 500 healthy adults of varied age, education, sex, and race (African American and Caucasian) for various indices of performance on the PASAT, including "Total Dyads" obtained across the four PASAT trials. In addition, we describe and present normative data on four other indices designed to quantify various aspects of performance on the PASAT: invalid responding, effects of varied information processing speed demands, and tendency to omit responses and to make arithmetic errors.

Abstracting and Indexing↗
PubMed2006

Association between dyads and correct responses on the Paced Auditory Serial Addition Task (PASAT).

The sensitivity of the Paced Auditory Serial Addition Task (PASAT) to working memory deficits may be enhanced by examining "dyads" (i.e., correct responses immediately preceded by a correct response) as a complement to the traditional total correct summary score. In a sample of 397 mostly African American (79%) healthy adults, total dyad and total correct scores were highly correlated (r = .96, p < .001); however, the magnitude of this association diminished in faster stimulus presentation trials, particularly among participants with impaired working memory abilities.

Adult↗
PubMed2005

Neuropsychological functioning in a cohort of HIV- and hepatitis C virus-infected women.

OBJECTIVE: To evaluate the neurocognitive function in 220 women enrolled in the Women's Interagency HIV Study (WIHS), a study of disease progression in women living with HIV/AIDS and in HIV-negative controls. METHODS: We evaluated the prevalence of abnormal neuropsychological (NP) results in hepatitis C virus (HCV)-positive compared with HCV-negative women in combination with HIV serostatus. RESULTS: NP impairment was significantly higher for HCV-positive women in comparison with HCV-negative women [odds ratio (OR), 2.03; 95% confidence interval (CI), 1.17-3.51]. Women co-infected with HCV and HIV demonstrated greater abnormal NP performance than those not infected with either, particularly if there was evidence of CD4 T-lymphocyte immunosuppression [> 200 x 10(6) CD4 cells/l (OR, 3.48; 95% CI, 1.49-8.15) and < or = 200 x 10(6) CD4 cells/l (OR, 5.38; 95% CI, 1.46-19.84)]. Women who were HCV-positive/HIV-positive and not taking antiretroviral therapy (ART) were more likely (OR, 7.03; 95% CI, 2.63-18.82) to demonstrate NP impairment than those who were HCV-negative/HIV-negative. In analyses controlling separately for education, intelligence quotient, depression, sedating drug use, head injury, ethnicity, and history of substance use, HCV continued to significantly predict NP impairment. The HCV effect did not reach significance when controlling for age in bivariate or multivariate analyses although the odds ratio for NP abnormalities in HCV-infected patients was only slightly reduced (ORs above 1.9). After testing for an interaction between age and infection status, we conducted age-stratified analysis and showed a significant effect of infection status for those aged under 40 years. CONCLUSIONS: The effect of aging on co-infected populations will require further study. This study has demonstrated the association of HCV with the risk of neurocognitive impairment in women living with HIV/AIDS and suggests that co-infection has an additive effect.

Adult↗
PubMed2005

Investigating neurocognitive features of hepatitis C virus infection in drug users: potential challenges and lessons learned from the HIV literature.

Studies of neurocognition in drug users with hepatitis C virus (HCV) infection are urgently needed but face many challenges. We review similarities between human immunodeficiency virus (HIV) and HCV infection in their neurocognitive features, discuss challenges associated with research among drug users, advocate that the HIV literature can usefully inform studies of HCV, and review findings by our group on neurocognition among substance users with HIV and/or HCV infection.

Adult↗
PubMed2005

The influence of executive functions, sensation seeking, and HIV serostatus on the risky sexual practices of substance-dependent individuals.

From a public health standpoint, identifying factors that contribute to risky sexual practices among substance-dependent individuals is critical, particularly in the context of HIV infection. This study examines the respective contributions of executive neurocognitive functions, sensation seeking, and HIV serostatus in predicting risky sexual practices among poly-substance users (with a history of dependence primarily for cocaine or cocaine/heroin). HIV+ (n=109) and HIV- (n=154) substance-dependent individuals were assessed using three neurocognitive tasks of executive functions: Stroop reaction time, delayed non-matching to sample, and the Iowa Gambling Task. Sensation seeking was assessed using the Sensation Seeking Scale-V. Greater sensation seeking was associated with more risky sexual practices among HIV+ participants, particularly among those who performed best on the Iowa Gambling Task. Our findings indicate that continued risk behavior among HIV+ drug users may be driven by sensation seeking (a personality trait common among drug users); however, the impact of executive functions is less clear.

Adult↗
PubMed2004

Cognitive impulsivity and HIV serostatus in substance dependent males.

HIV-seropositive (HIV+) drug users show impaired performance on measures of integrity of prefrontal-subcortical systems. The Iowa Gambling Task (GT) is mediated primarily through ventromedial-prefrontal systems, and poor performance on this measure ("cognitive impulsivity") is common among substance dependent individuals (SDIs) as well as patients with disease involving prefrontal-subcortical systems (e.g., Huntington disease). We hypothesized that HIV+ SDIs might be more vulnerable to cognitive impulsivity when compared with HIV-seronegative (HIV-) SDIs because recent studies report evidence of additive effects of HIV serostatus and drug dependence on cognition. Further, working memory is considered a key component of GT performance and is reliably impaired among HIV+ SDIs compared to controls. We administered the GT to 46 HIV+ and 47 well-matched HIV- males with a past or current history of substance dependence. In addition, we evaluated correlations between subjects' scores on the GT and on a delayed nonmatch to sample (DNMS) task in order to test if working memory deficits accounted for cognitive impulsivity among the HIV+ subjects. The HIV+ subjects performed significantly more poorly on the GT compared to the HIV- group but this effect could not be explained by working memory deficits. Implications of these findings for future basic and applied studies of HIV and substance dependence are discussed.

Adolescent↗
PubMed2004

Impaired decision making related to working memory deficits in individuals with substance addictions.

This study examined whether individuals with substance dependence (ISDs) show impairments in working memory and whether there is a relationship between their impairments in decision making as measured by the gambling task (GT) paradigm and working memory as measured by a delayed nonmatching to sample (DNMS) task. Using the GT, 11% of healthy control participants and 61% of ISDs opted for choices with high immediate gains in spite of higher future losses. For the ISDs and controls with equal GT impairments, the ISDs performed significantly lower than controls on the DNMS task. The nonimpaired ISDs on the GT also performed significantly worse than matched controls on the DNMS task. The DNMS task deficit in ISDs was across all delay times, suggesting the deficit may lie in the "executive" process of working memory, which supports earlier findings (E. M. Martin et al., 2003). The authors suggest that the prefrontal cortex hosts multiple distinct mechanisms of decision making and inhibitory control and that ISDs may be affected in any one or combination of them.

Adult↗
PubMed2003

Delayed nonmatch-to-sample performance in HIV-seropositive and HIV-seronegative polydrug abusers.

Working memory (WM) deficits are common in HIV-seropositive (HIV+) individuals and can be amplified by manipulating a variety of task parameters, such as increasing memory load or information complexity. The authors investigated the role of timing in HIV-associated WM defects by varying the amount of time required to maintain information online while holding memory load and information complexity constant. The authors studied 50 HIV+ and 35 HIV-seronegative (HIV-) polydrug abusers abstinent at testing and well-matched on demographic variables. The HIV- group outperformed the HIV+ group across all stimulus-response time delays. HIV-associated WM defects are not critically dependent on the amount of time stimulus representations must be maintained and might be attributed to impaired encoding or retrieval of stimulus representations.

Adult↗
PubMed2002

Neuropsychological functioning in a cohort of HIV infected women: importance of antiretroviral therapy.

We evaluated neurocognitive function in 149 HIV-seropositive and 82 seronegative women enrolled in the Women's Interagency HIV Study (WIHS), a large multi-center study of disease progression in women living with HIV/AIDS. We evaluated the prevalence of abnormal neuropsychological (NP) test findings in HIV-seropositive and seronegative women and factors associated with increased risk of abnormal NP test performance. Risk of NP impairment was no higher for HIV positive women receiving antiretroviral therapy at testing than for HIV-negative women (OR = 1.00). However, the risk of abnormal NP performance increased significantly for seropositive women not receiving antiretroviral therapy (OR = 2.43). Further, treatment status was a significant predictor of NP impairment in a multivariate analysis that included viral load (OR = 1.48) and CD4 count (OR = 1.08) which were not significant. The multivariate analyses controlled for substance use, age, education, head injury, ethnicity, estimated IQ, and psychological distress. This study emphasizes the critical association of antiretroviral therapy with the risk of neurocognitive impairment in women living with HIV/AIDS.

Adult↗
PubMed2002

Immune-specific immunoglobulin G-mediated enhancement of human immunodeficiency virus-induced IFN-alpha production.

Interferon-alpha (IFN-alpha) is synthesized as an integral part of innate immunity to viral infection. We previously provided preliminary evidence that antibody-containing serum from HIV-infected individuals enhanced HIV-induced production of IFN-alpha. Subsequently, preparations of pooled human immunoglobulin G (IgG) have also been shown to enhance poliovirus (PV)-induced IFN-alpha production. The current work establishes IgG as the serum mediator that enhances induction of IFN-alpha by HIV. Our studies also establish the ability of sera from individual subjects to enhance PV-induced IFN-alpha production. HIV-induced IFN-alpha production was enhanced maximally by >4000-fold and by an average of 25-fold. Sera from 74 people enhanced PV- induced IFN-alpha from undetectable levels to an average of 615 units (range 7-4679 units). The ability of individual sera to enhance IFN-alpha production by HIV and PV persisted undiminished in patients with AIDS. IgG-mediated enhancement of IFN-alpha production was similar to that induced by IgG and PV and was blocked by IgG Fc fragments. Demonstration of the selective enhancement of HIV-induced IFN-alpha production by IgG from HIV-seropositive individuals provides further evidence for the existence of antigen-specific upregulation of a critical component of innate antiviral immunity by the adaptive Th2 immune response.

Adult↗
PubMed2002

Executive function in schizophrenia: is it linked to psychosis and poor life functioning?

The authors examined the relationship of major aspects of executive function to acute psychosis and long-term outcome in patients enrolled in a 15-year study of the natural history of psychosis. They evaluated 157 patients, including 42 schizophrenic, 42 other psychotic, and 73 nonpsychotic psychiatric patients 15 years after index hospitalization. Patients were administered the Wisconsin Card Sorting Test (WCST) and measures of psychosis and posthospital adjustment. Schizophrenia patients performed significantly worse than both nonschizophrenic psychiatric control groups on WCST indices, regardless of psychosis. Aspects of executive function were impaired in schizophrenia patients with severe deficits in their level of overall functioning and outcome and also in many with only moderate impairment in overall functioning; however, these deficits were seen to a greater degree in schizophrenia patients with very poor overall functioning. Executive function deficits appear to be a core component of schizophrenia rather than an effect of acute psychotic disorganization, and are associated with long-term outcome.

Activities of Daily Living↗