39 Neurocognitive Function in People Living with HIV from Tijuana: a Comparison Between Norms for Latin-American Population and Norms for US-Mexico Border Region

Abstract

Objective:

Global neurocognitive impairment (NCI) has been reported in white people living with HIV/AIDS (PLWHA) in 40%. In Latino populations there have been variable rates described from 30 to 77%. This variation has to do with the lack of normative data for Latino population and the application of norms for English-speakers, increasing the probability of misidentification of NCI. Thus, recognizing which are the best norms available for the Mexican population is important for the accurate identification of NCI. The aim of the present study was to investigate the rate and pattern of HIV associated neurocognitive impairment (NCI) and to compare rates of NCI between rates calculated using norms for the Latin-American population (NLAP) and norms for the US-Mexico border region (NP-NUMBRS).

Participants and Methods:

CIOMS international ethical guidelines for the participation of human subjects in health research were followed. 82 PLWHA living in Tijuana (Mexico) participated in the study (Age: Mean=39.6, SD=10.9; 28.3% Female; Years of education: Mean=8.5, SD=3.6). PLWHA were recruited from the board-and-care home “Las Memorias” (73.4% on antiretroviral therapy; Years since HIV diagnosis: Mean=9.9, SD=7.1). Participants completed a neuropsychological test battery sensitive to detect HIV associated NCI that assessed four cognitive domains (verbal fluency, speed of information processing, executive function and learning/memory). Raw scores in these tests were transformed to percentiles using LAPN and transformed to T-scores using NP-NUMBRS. T-scores were averaged across tests to compute domain specific and global impairment scores. NCI was defined as percentile scores <16 and T-scores < 40. McNemar’s tests were used to compare the rate of NCI utilizing NLAP vs NP-NUMBRS.

Results:

According to NLAP, rates of global NCI were about 13.4%. Utilizing NP-NUMBRS rates of global NCI were about 34.1%. However, there is a positive and significant correlation between Global Neurocognitive Function score in PLWHA according to NLAP and NP-NUMBRS (r=0.66, p<.05). Rates of global NCI in PLWHA were significantly lower when using LAP norms (McNemar Chi-Square=29.89; p<.001). Regarding the pattern of NCI according both norms learning and memory was the most affected cognitive domain with 34% of impairment according to NLAP vs 51% of impairment according to NP-NUMBRs.

Conclusions:

Utilizing NP-NUMBRS, rates of NCI are consistent with findings of prior studies. Employing norms for LAP the rates of NCI are lower that the ones reported in the literature. This is an important finding since PLWHA included in the sample have several vulnerable factors such as deportation, prostitution, drug abuse and discrimination for sexual preference, factor that could impact cognition. The pattern of neurocognitive function was also similar to those of prior studies in HIV. To accurately make NCI diagnosis it is important to use norms that consider specific characteristics of the population. The diagnosis of NCI is important since these deficits present a strong risk of concurrent problems in a wide range of health behaviors like medication non-adherence in PLWHA.