The above results, while admittedly tentative, are encouraging in several respects. First, the NP test battery that was chosen and adapted for use in this study was understood and accepted by the Chinese HIV+ and HIV− participants, from both urban and rural areas of the country, whose education levels ranged widely (4 to 18 years). Second, the battery, which was translated into Mandarin, appears to hold considerable promise for identifying and characterizing behavioral effects of HIV brain involvement in China. Finally, the consistent HIV effects across countries and the modest country effects in the current study () suggest that these tests may have reasonable cross-cultural equivalence. Further psychometric analyses with much larger samples of neurologically normal and abnormal people are needed to confirm this.
The NP test batteries between the two countries were identical except for three NP tests that were substituted for the Chinese individuals to increase the cross-cultural suitability (Spatial Span for Letter Number-Sequencing; Color-Trails II for Trail Making Test B; and Action Fluency for Letter Fluency). The first test substitution was chosen to respect findings of factor analyses of the WMS showing that Spatial Span and Letter Number-Sequencing grouped with the same factor (WMS-III, 1997). In addition, Color-Trails II was designed to tap similar sequencing and processing requirements as Trail Making B (Maj et al., 1993
). Finally, Action and Letter Fluency are both tests of word generation that tap into frontal neural systems (Woods et al., 2005
). Despite these similarities, slight differences in tests may have influenced the HIV effects observed in the China and U.S. cohorts. To check for this possibility, we re-computed the overall mean scaled scores without these tests and found identical results ().
Country effects on two NP Domain scores are difficult to interpret for two reasons: the significant education differences between the U.S. and China groups probably influenced there results to some degree, and different tests were used for the Verbal Fluency domain in the two countries (Letter Fluency for U.S. and Action Fluency for China). Nevertheless, the most important findings in these ANO-VAs were the consistently significant HIV effects for the total test battery and all seven ability domains, and the absence of any significant interaction effects. These results suggest comparable, significant effects of HIV on NP functioning in both countries.
Closer inspection of the pattern of HIV-related deficits reveals that NP impairment was dominated by deficits in abstraction/executive function, information processing speed, as well as learning in Chinese HIV+ individuals (). This pattern of deficits is generally consistent with what has been shown in Western studies (Cysique et al., 2006
; Grant & Martin, 1994
; Reger et al., 2002
High rates of depressed mood in HIV-infected persons were not significantly associated with NP performance in the United States or China. These preliminary results are consistent with a large body of literature showing that depressive symptoms do not account for neurocognitive impairment in HIV-infected individuals (Cysique et al., 2007
; Goggin et al., 1997
). In contrast, depressive complaints were strongly associated with self-report of neurobehavioral problems in both countries. This finding also is consistent with what has been reported in North American HIV cohorts (Carter et al., 2003
; Rourke et al., 1999
Consistent with U.S. findings on the impact of HIV-associated neurocognitive impairment on instrumental activities of daily living (Heaton et al., 2004a
) and employment (Albert et al., 1995
; Heaton et al., 1994
), we found, in the Chinese HIV+ group, a correlation between NP functioning and complaints of cognitive difficulties in everyday life (i.e., PAOFI), and also a modest association between unemployment status and overall level of NP performance. However, given the major cultural and lifestyle differences in these two countries, much more research is needed to understand the functional consequences of general and specific neurocognitive deficits in China. In particular, because NP impairment has been shown to predict poor medication adherence among HIV+ individuals in the United States (Hinkin et al., 2004
), it would be important to determine whether NP-impaired HIV+ people in China are at similar risk for poor medication management and possibly worse antiretroviral treatment outcome (d’Arminio Monforte et al., 1998
A major limitation of this pilot study is the absence of established normative standards for Chinese people on the NP test battery. Although NP norms with appropriate demographic corrections were available for the U.S. participants, it is considered likely that demographic effects are different in China. For example, very low levels of education and illiteracy are not represented in the U.S. normative samples, but such backgrounds still are relatively common in China (especially in the rural areas). As a consequence, larger education effects might be expected within our China study groups. Unfortunately, our sample sizes were much too small to address this problem in the current study. Future large scale studies of healthy Chinese with diverse backgrounds will be needed to develop norms that can be used confidently to classify disease-related “impairments” in individual cases. However, the robust HIV effect sizes in our demographically matched Chinese samples () strongly suggest that these tests have potential for identifying individuals within the Chinese population who are suffering from CNS complications of HIV. Thus, our results would support continued work to better understand the nature and causes of NP performance differences in the normal Chinese population, as well as in people affected by HIV infection and other diseases of the CNS.