Desiree Byrd

Sex Differences in Visual Recognition Memory: Support for a Sex-Related Difference in Attention in Adults and Children

The selectivity hypothesis of Meyers-Levy (1989) proposes that cognitive sex differences reflect underlying differences in information processing between males and females. Males are considered to be more likely to organize information in a self-related manner, whereas females are more likely to adopt a comprehensive approach to information processing. We tested this hypothesis in children (10-15 years) and adults using recognition memory tasks. Tests were devised which employed male-oriented objects, female oriented objects, or random objects. In both the child and adult samples, females performed significantly better than males on tests using random and female-oriented objects. Males performed at the level of females only when tested for recognition of male-oriented objects. These results demonstrate that this sex difference is present prior to puberty and support the concept of sex differences in information processing.

Neurocognitive impact of substance use in HIV infection

Background: To determine how serious a confound substance use (SU) might be in studies on HIV-associated neurocognitive disorder (HAND), we examined the relationship of SU history to neurocognitive impairment (NCI) in participants enrolled in the Central Nervous System HIV Antiretroviral Therapy Effects Research study. Methods: After excluding cases with behavioral evidence of acute intoxication and histories of factors that independently could account for NCI (eg, stroke), baseline demographic, medical, SU, and neurocognitive data were analyzed from 399 participants. Potential SU risk for NCI was determined by the following criteria: lifetime SU Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition diagnosis, self-report of marked lifetime SU, or positive urine toxicology. Participants were divided into 3 groups as follows: no SU (n = 134), nonsyndromic SU (n = 131), syndromic SU (n = 134) and matched on literacy level, nadir CD4, and depressive symptoms. Results: Although approximately 50% of the participants were diagnosed with HAND, a multivariate analysis of covariance of neurocogntive summary scores, covarying for urine toxicology, revealed no significant effect of SU status. Correlational analyses indicated weak associations between lifetime heroin dosage and poor recall and working memory and between cannabis and cocaine use and better verbal fluency. Conclusions: These data indicate that HIV neurocognitive effects are seen at about the same frequency in those with and without historic substance abuse in cases that are equated on other factors that might contribute to NCI. Therefore, studies on neuroAIDS and its treatment need not exclude such cases. However, the effects of acute SU and current SU disorders on HAND require further study.

INCREASING CULTURALLY COMPETENT NEUROPSYCHOLOGICAL SERVICES FOR ETHNIC MINORITY POPULATIONS: A CALL TO ACTION

US demographic and sociopolitical shifts have resulted in a rapidly growing need for culturally competent neuropsychological services. However, clinical neuropsychology as a field has not kept pace with the needs of ethnic minority clients. In this discussion we review: historical precedents and the limits of universalism in neuropsychology; ethical/professional guidelines pertinent to neuropsychological practice with ethnic minority clients; critical cultural considerations in neuropsychology; current disparities germane to practice; and challenges to the provision of services to racial/ethnic minority clients. We provide a call to action for neuropsychologists and related organizations to advance multiculturalism and diversity within the field by increasing multicultural awareness and knowledge, multicultural education and training, multicultural neuropsychological research, and the provision of culturally competent neuropsychological services to racial/ethnic minority clients. Lastly, we discuss strategies for increasing the provision of culturally competent neuropsychological services, and offer several resources to meet these goals.

Differential predictors of medication adherence in HIV: findings from a sample of African American and Caucasian HIV-positive drug-using adults.

Modest or even occasional nonadherence to combined antiretroviral therapy (cART) can result in adverse clinical outcomes. African Americans demonstrate lower rates of adherence than Caucasians or Latinos. Identifying factors that influence medication adherence among African Americans is a critical step toward reducing HIV/AIDS disease progression and mortality. In a sample of 181 African American (n=144) and Caucasian (n=37) HIV-positive drug-using individuals [age (M=42.31; SD=6.6) education (M=13.41; SD=2.1)], we examined the influence of baseline drug use, literacy, neurocognition, depression, treatment-specific social support, and patient satisfaction with health care provider on medication adherence averaged over the course of 6 months (study dates 2002-2006). Our findings suggest differential baseline predictors of medication adherence for African Americans and Caucasians, such that patient satisfaction with provider was the strongest predictor of follow-up medication adherence for African Americans whereas for Caucasians depressive symptoms and treatment-specific social support were predictive of medication adherence (after controlling for duration of drug use).

Motor Function and Human Immunodeficiency Virus-Associated Cognitive Impairment in a Highly Active Antiretroviral Therapy-Era Cohort

BACKGROUND Cognitive impairment has long been recognized as a manifestation of human immunodeficiency virus (HIV) infection. However, highly active antiretroviral therapy (HAART) has altered the neurologic manifestations of HIV. OBJECTIVES To develop a measure to quantify the motor abnormalities included in the original descriptions of HIV-associated dementia (HAD); to determine whether motor, affective, and behavioral dysfunction predict cognitive impairment; and to determine whether quantitative motor testing is a helpful adjunct in the diagnosis of HAD in a complex population from the HAART era. DESIGN Neurologic and neuropsychological data were collected from the Manhattan HIV Brain Bank, a longitudinal cohort study of patients with advanced HIV. The HIV-Dementia Motor Scale (HDMS) was developed and validated and cognitive and affective or behavioral function was quantified using global neuropsychological T scores, the Beck Depression Inventory (BDI), and an independent assessment of apathy. Relationships among cognitive, motor, affective, and behavioral performance were examined using correlation, linear regression, and analyses of variance. SETTING An urban AIDS research center. PARTICIPANTS A total of 260 HIV-positive, predominantly minority patients. MAIN OUTCOME MEASURES The HDMS scores and global neuropsychological T scores. RESULTS The HDMS and BDI scores were independent predictors of cognitive impairment. Significant cognitive impairment was found in patients with motor dysfunction. Patients diagnosed as having HAD had a greater degree of motor impairment than those with other neurocognitive diagnoses. CONCLUSIONS Motor, affective, and behavioral abnormalities predict cognitive impairment in HIV-positive patients in this HAART-era cohort. The HDMS may be useful in the assignment of HIV-associated neurocognitive impairment in HIV populations in which normative data or neuropsychological test design is not optimal.

Effects of Stereotype Threat, Perceived Discrimination, and Examiner Race on Neuropsychological Performance: Simple as Black and White?

The purpose of the current study was to examine the predictive roles of stereotype threat and perceived discrimination and the mediating role of examiner-examinee racial discordance on neuropsychological performance in a non-clinical sample of African American and Caucasian individuals. Ninety-two African American (n = 45) and Caucasian (n = 47) adults were randomly assigned to either a stereotype threat or non-threat condition. Within each condition, participants were randomly assigned to either a same race or different race examiner. All participants underwent neuropsychological testing and completed a measure of perceived discrimination. African Americans in the stereotype threat condition performed significantly worse on global NP (Mz = -.30, 95% confidence interval [CI] [-0.07, -0.67] than African Americans in the non-threat condition (Mz = 0.09, CI [0.15, 0.33]. African Americans who reported high levels of perceived discrimination performed significantly worse on memory tests when tested by an examiner of a different race, Mz = -1.19, 95% CI [-1.78, -.54], than African Americans who were tested by an examiner of the same race, Mz = 0.24, 95% CI [-0.24, 0.72]. The current study underscores the importance of considering the role of contextual variables in neuropsychological performance, as these variables may obscure the validity of results among certain racial/ethnic groups.

CCR2 on CD14+CD16+ monocytes is a biomarker of HIV-associated neurocognitive disorders

Objective: To evaluate C-C chemokine receptor type 2 (CCR2) on monocyte subsets as a prognostic peripheral blood biomarker of HIV-associated neurocognitive disorders (HAND). Methods: We characterized monocyte populations in HIV-infected individuals with and without HAND from 2 cohorts and assessed their transmigration across an in vitro model of the human blood-brain barrier (BBB). We examined CCR2 expression among the monocyte populations as a prognostic/predictive biomarker of HAND and its functional consequences in facilitating monocyte diapedesis. Results: We determined that CCR2 was significantly increased on CD14+CD16+ monocytes in individuals with HAND compared to infected people with normal cognition. CCR2 remained elevated irrespective of the severity of cognitive impairment, combined antiretroviral therapy status, viral load, and current or nadir CD4 T-cell count. There was no association between CCR2 on other monocyte populations and HAND. There was a functional consequence to the increase in CCR2, as CD14+CD16+ monocytes from individuals with HAND transmigrated across our model of the human BBB in significantly higher numbers in response to its ligand chemokine (C-C) motif ligand 2 (CCL2) compared to the cell migration that occurred in people with no cognitive deficits. It should be noted that our study had the limitation of a smaller sample size of unimpaired individuals. In contrast, there was no difference in the transmigration of other monocyte subsets across the BBB in response to CCL2 in seropositive individuals with or without HAND. Conclusions: Our findings indicate CCR2 on CD14+CD16+ monocytes is a novel peripheral blood biomarker of HAND.

State of Multicultural Neuropsychological Assessment in Children: Current Research Issues

Scientific attention to cultural considerations in child neuropsychological assessment has not developed parallel to the focus these issues have received in adult and elderly neuropsychological assessment. There are limited data on the presence, magnitude, etiology, and implications of culture-related differences in cognitive test performance among children. This preliminary report reviews the available empirical literature on the current state of multicultural neuropsychological assessment in children. The review identified articles by searching PubMed and PsycINFO databases, and the tables of contents of Developmental Neuropsychology and Child Neuropsychology from 2003–2008. Of the 1,834 abstracts reviewed, ten papers met inclusion criteria for the review. Five studies were completed in America; four of these compared performance between ethnic groups while the fifth examined neighborhood level poverty indicators exclusively within African-American children. Of the five international studies, all established local normative data and/or were exploratory investigations of neuropsychological functions in specific cultural groups, including Taiwanese infants, South African youth, and bilingual British children. Taken together, the results yield important clinical and research data that begin to inform many of the complex and fascinating mechanisms by which ethnic identity and culture impact cognitive development and the neuropsychological assessment of children. A critique of the existing literature and directions for future research are provided.

Major Depressive Disorder, Cognitive Symptoms, and Neuropsychological Performance among Ethnically Diverse HIV + Men and Women

Major depressive disorder (MDD), cognitive symptoms, and mild cognitive deficits commonly occur in HIV-infected individuals, despite highly active antiretroviral therapies. In this study, we compared neuropsychological performance and cognitive symptoms of 191 HIV-infected participants. Results indicated that participants with a formal diagnosis of current MDD performed significantly worse than participants without MDD in all seven neuropsychological domains evaluated, with the largest effect sizes in information processing speed, learning, and memory. In addition, a brief assessment of cognitive symptoms, derived from a comprehensive neuromedical interview, correlated significantly with neurocognitive functioning. Participants with MDD reported more cognitive symptoms and showed greater neurocognitive deficits than participants without MDD. These findings indicate that HIV-infected adults with MDD have more cognitive symptoms and worse neuropsychological performance than HIV-infected individuals without MDD. The results of this study have important implications for the diagnosis of HIV-associated neurocognitive disorders (HAND).

Impact of opiate addiction on neuroinflammation in HIV

To investigate the independent and interactive effects of opiate addiction and HIV on neuroinflammation, we measured microglial/macrophage activation and astrogliosis in multiple regions of human brain. Samples of thalamus, frontal gray matter, and frontal white matter were obtained from 46 individuals categorized as: HIV negatives, HIV-negative opiate addicts, HIV positives, HIV-positive opiate addicts, HIV encephalitis (HIVE), and HIVE opiate addicts. Activated brain microglia/macrophages and astrocytosis were quantified by morphometric analysis of immunohistochemical stains for CD68, HLA-D, CD163, and GFAP. The effects of HIV grouping, opiate addiction, and their interaction on expression of the markers were examined in a series of two-way ANOVAs. In opiate addicts, there was generally higher baseline expression of CD68 and HLA-D in HIV negatives, and lower expression in HIV and HIVE, compared to individuals without opiate abuse. Thus, for these markers, and for GFAP in frontal gray, opiates were associated with attenuated HIV effect. In contrast, for CD163, opiates did not significantly alter responses to HIV, and HIV effects were variably absent in individuals without opiate abuse. The divergent impact that opiate addiction displays on these markers may suggest a generally immunosuppressive role in the CNS, with decreased HIV-associated activation of markers CD68 and HLA-D that potentially reflect neurotoxic pathways, and preservation of CD163, thought to be an indicator of neuroprotective scavenger systems. These results suggest a complex impact of opiates on neuroinflammation in baseline and virally stimulated states.