The Hispanic population represents the largest and fastest growing racial/ethnic minority group in the U.S., and has also been disproportionately affected by the HIV/AIDS epidemic. This study is the first to begin to systematically characterize the neuropsychological sequelae of HIV-1 infection within an advanced HIV+ Hispanic cohort utilizing a biopsychosociocultural framework to inform measurement of sociocultural factors that may be involved in the expression of neurologic illness among HIV+ Hispanic individuals. This study is also the first of which we are aware to begin to disentangle the role of sociocultural factors (reading level and SES) from ethnicity in the prediction of neuropsychological test performance among HIV+ Hispanic participants. The current results suggest that the pattern of neuropsychological impairment demonstrated by our Hispanic cohort is consistent with other reports of HIV/AIDS-related neuropsychological impairment and higher prevalence of global neuropsychological impairment compared to previous reports with more non-Hispanic White cohorts. Further, the present findings highlight the prominent and separable roles of reading level and ethnicity in neuropsychological test performance.
Hispanic participants were primarily of Caribbean descent, and this is consistent with the demographic characteristics of the area in which this study was conducted (East Harlem, New York City; NYC Department of Health and Mental Hygiene, 2006
). To characterize the neuropsychological sequelae of HIV+ Hispanic participants, we conducted a series of analyses exclusively within the Hispanic group. We found that 71% of the Hispanic group was globally neuropsychologically impaired, with the great majority (95%) of those demonstrating a mild to moderate level of impairment. When the Hispanic NP-impaired group was compared with the Hispanic NP-normal group, the former demonstrated the greatest deficits in the areas of processing speed, abstraction/executive functioning, fine motor skills, and learning. This pattern of deficits is consistent with previous reports of HIV-associated neuropsychological sequelae and with frontal-striatal involvement, suggesting that these deficits truly represent HIV disease- induced CNS abnormality in this group (Becker et al., 1997
; Grant & Heaton, 1990
; Heaton et al., 1995
; Heaton et al., 2004
; Martin, Sorensen, Edelstein, & Robertson, 1992
; White et al., 1997
). Parallel analyses conducted with the non-Hispanic White group revealed a similar pattern of results thereby bolstering support for the detection of HIV-related neuropsychological sequelae within both ethnic groups.
The present study observed a higher prevalence of global neuropsychological impairment (70%) among the HIV+ Hispanic group than has been previously reported with samples with greater proportions of HIV+ non-Hispanic white participants (Heaton et al., 1995
; Heaton et al., 2004
). The results also demonstrated that time since HIV diagnosis and substance abuse/dependence were not associated with ethnicity or neuropsychological function. Thus, this finding provides preliminary support for Wojna et al.'s (2006)
report that HIV+ Puerto Rican women residing in Puerto Rico had a higher prevalence of HIV-Associated Dementia (HAD), and those findings by examining global and specific aspects of NP functioning (rather than just an HAD diagnosis) with U.S. Hispanic individuals of Caribbean origin that include a majority of men (78%) in the sample. Still, these findings must be interpreted with caution as several factors may be influencing these results.
The greater pervasiveness of observed neuropsychological impairment among the HIV+ Hispanic participants in this study compared to previous studies is likely to be associated with several factors, including: 1) cultural bias of the neuropsychological measures used in this study (e.g., inadequate normative data, cultural variability in response set, participant/examiner interactions, test-taking attitudes, etc.; Manly, 2005
), 2) methodological and/or sampling differences between the current and previous studies on HIV+ Hispanic & non-Hispanic white participants, and/or 3) bio-behavioral factors associated with differing Hispanic populations (e.g., genetics, health disparities, medication adherence, etc.). While certainly a more speculative hypothesis, it is also possible that there is a lowered threshold for the onset of HIV-associated neuropsychological sequelae secondary to reduced cognitive reserve within this HIV+ Hispanic population given their myriad sociocultural risk factors (educational, socioeconomic, and health disparities; Durvasula et al., 2001
; Manly et al., 2003
; Satz et al., 1993
; Stern et al., 1996
). The current findings, in concert with the recent findings of Wojna et al. (2006)
and a report of earlier onset of Alzheimer Disease symptoms among Hispanic participants compared to non-Hispanic White participants (Clark et al., 2005
), make this latter hypothesis worth future examination.
The significant association between reading level and neuropsychological functioning observed in this study goes far to contextualize the current findings. Hispanic individuals are more likely than non-Hispanic White individuals to live in poverty and reside within geographically concentrated urban areas (Llorente, Ponton, Taussig, & Satz, 1999
; The Pew Hispanic Center, 2005
; U.S. Census Bureau, 2003b
), both of which are risk factors for lower per pupil resource allocation (Carey, 2004
). Moreover, while national literacy scores have risen for African- and Asian- Americans, and have remained essentially unchanged for non-Hispanic White individuals between 1992 and 2003, they have decreased significantly for Hispanic individuals (NCES, 2006
). Therefore, although our Hispanic sample was relatively well educated in terms of duration of schooling (M
=12.5 years), this appears to be strongly mitigated by their lower reading level, which serves as a proxy for poorer quality of education. Ultimately, such educational disparities appear to put HIV+ Hispanic individuals at greater risk for poorer neuropsychological test performance.
SES was not associated with neuropsychological functioning in this study. However, due to the fact that this study's SES measure was actually a proxy (median income based on zip code), which used household ethnicity as part of the determination of SES, caution must be taken when interpreting this finding. This study's measure of SES may lack the specificity necessary to draw more definitive conclusions regarding the association between SES and neuropsychological functioning in this population.
Our most important hypotheses, regarding the combined roles of sociocultural variables (ethnicity, reading level, SES) and disease progression (CD4 count) in the prediction of neuropsychological functioning, were partially supported. As predicted, we found that only reading level significantly predicted global neuropsychological functioning, learning, and attention/working memory. In contrast to our hypotheses, only ethnicity significantly predicted abstraction/executive functioning. Posthoc analyses revealed that neither English-language verbal skills nor bilingual ability uniquely predicted abstraction/executive functioning. However, our current assessment of English and Spanish language fluency was circumscribed to brief verbal fluency measures, and more comprehensive assessment may have yielded different results. Further research is needed to examine the association between English-language fluency, bilingual ability, and abstraction/executive functioning.
Beyond potential language considerations, the unique role of ethnicity in abstraction/executive functioning may also be associated with acculturation, a construct not examined in the current study. Previous research suggests that lower acculturation (to majority, mainstream culture) is associated with poorer performance on measures of abstraction/executive functioning (Arnold, Montgomery, Castaneda, & Longoria, 1994
). It is possible that the process of nonverbal, abstract reasoning is more culturally mediated than other neuropsychological processes within the Hispanic population. However, additional research specifically examining these associations is needed in order to test this hypothesis.
The findings on the association between ethnicity and abstraction/executive function highlight a limitation of this study, e.g., that it lacked the resources to do more comprehensive cultural evaluations to examine within group variation among Hispanic participants. Additional research is needed to replicate and expand the current findings with larger, more thoroughly characterized Hispanic samples of English- and Spanish-speakers to better evaluate the prevalence of HIV-associated neuropsychological sequelae within this population and to examine the role of with-in group variation on several sociocultural factors (acculturation, language, etc.) that may associated with neuropsychological test performance.
Given the relative homogeneity of our Hispanic sample, one could make the argument that the generalizability of the current findings is limited to primarily English-speaking Hispanic individuals of Caribbean origin. While this may indeed be the case, it is alternately possible that the current findings are applicable to other Hispanic subpopulations, and potentially other racial/ethnic groups who experience similar sociocultural disadvantages. Thus, more research is needed to replicate this study with other Hispanic subpopulations as Hispanic individuals tend to exhibit nonrandom, preferential geographical affinity that could interact with other demographic/cultural factors to create distinct patterns of neuropsychological test performance (Llorente et al., 1999
The lack of demographically corrected norms, which include ethnicity, for English- speaking Hispanic individuals represents a major limitation, and within the field more broadly, to all neuropsychological studies of U.S. Hispanic individuals. While we utilized the best available norms, they did not address current educational disparities and the current findings provide strong support for the fact that even relatively well educated Hispanic individuals are likely to experience poorer quality of education compared to their non-Hispanic White counterparts. Additional research using improved norms for English-speaking Hispanic individuals is needed.
An additional limitation of this study is that HIV-seronegative controls were not included. While inclusion of such a control group would certainly enhance the current study, the goal of this study was not to compare HIV-seropositives to seronegative controls. Rather, this study sought to characterize the NP function of HIV-seropositive Hispanic participants, and to examine the combined roles of sociocultural variables in the prediction of their NP test performance. As a first step in a new area of investigation, this study met its goals using the current sample.
A final study limitation relates to the limited assessment of literacy. Consistent with previous research, this study's assessment of literacy was limited to evaluation of reading level based upon a single word reading test (WRAT-3 Reading subtest) as a proxy for quality of education (Byrd et al., 2005
; Constantino et al., 2007
; Manly et al., 2002
; Ryan et al., 2005
). Consequently, the current results cannot be used to make broad generalizations regarding the association between literacy and neuropsychological test performance, but rather provide initial insight into the role of quality of education on neuropsychological test performance among those with advanced HIV/AIDS.
Despite these limitations, this study has three important strengths. This study is the first to suggest that HIV+ Hispanic participants with advanced disease demonstrate a pattern of neuropsychological sequelae that is consistent with the frontal-striatal pattern observed in HIV-induced CNS disease. Second, this study is the first to systematically evaluate HIV-related neuropsychological complications within a sample of advanced HIV+ Hispanic participants in the U.S. In using a larger and better characterized Hispanic group with a demographically and medically equivalent non-Hispanic White comparison group, this study was able to more confidently make inferences based on the current findings than previous studies with smaller or less thoroughly characterized Hispanic groups. Third and finally, in utilizing biopsychosociocultural theory to inform hypotheses, this investigation will hopefully help to move NeuroAIDS research beyond categorical racial/ethnic variables as terminal explanatory constructs of neuropsychological functioning in favor of more conceptually and theoretically driven constructs, such as quality of education and SES (Helms, Jernigan, & Mascher, 2005
With regard to disease, this study's results affirm the utility of commonly used neuropsychological test measures in the detection of HIV-related neuropsychological impairment among HIV+ Hispanic participants. However, the results also demonstrate the need for providing culturally competent neuropsychological evaluations as an integral part of the standard of care. Specifically, it is recommended that a comprehensive sociocultural evaluation (e.g., literacy, quality of education, acculturation, linguistic information, etc.) and improved normative data be utilized. Integration of such information could potentially improve the interpretation of neuropsychological test data, aid in making more precise cognitive-diagnoses, and assist in developing culturally tailored treatment recommendations.
Research suggests HIV-related neuropsychological impairment is related to significant functional impairment across a spectrum of areas, including medication adherence (Hinkin et al., 2002
; Hinkin et al., 2004
; Heaton et al., 2004
; Rivera Mindt et al., 2003
). If it is indeed the case that a high rate of neuropsychological impairment is present among HIV+ Hispanic individuals as this and previous research suggests (Wojna et al., 2006
), then research is needed to develop culturally tailored interventions to address likely associated functional impairments (particularly in the area of medication adherence - a critical factor for positive health outcomes) - with public policy support to implement such interventions within Hispanic communities. Public policy would also go far to address the dearth of linguistically/culturally competent neuropsychologists currently in practice and research in the U.S. in order to better provide evaluation and treatment services to HIV+ Hispanic individuals. In sum, the current results suggest that HIV+ Hispanic individuals with global neuropsychological impairment demonstrate a pattern of impairments consistent with other reports of HIV-related CNS complications. Moreover, this study highlights the need to consider sociocultural factors in the interpretation of neuropsychological test performance with this population. Given the importance of sociocultural factors in the neuropsychological evaluation of HIV+ Hispanic individuals, it is likely that these same factors play important roles for consideration at every stage of the disease, from prevention to palliative care, and more research is needed to better understand these factors at every stage of care.