The study was one of a series investigating the development
of an English cohort of people who had been born with HIV or acquired it as babies,
the AALPHI (Adolescents and Adults Living with Perinatal HIV) Cohort.
Data from the cohort were first published by Professor Ali Judd in 2016, with similar results to the present study. The results from both studies
were presented as Z-scores. A Z-score is defined as the degree to which observed
results differ from population norms. A Z-score of zero means that the result
is precisely in line with the norm. A result below minus one means that the result
falls within the bottom 16% of results; below minus two indicates being in the bottom
2.5% of results.
In the previously published study the global average Z-score was -0.81
in young people who had had an AIDS-related condition, indicating a result
falling within the lowest 20% or so of results. In the other
HIV-positive and HIV-negative young people average scores were -0.45 and ‑0.32 respectively, indicating results falling
within or just above the lower one-third of results.
In the present study, 234 HIV-positive people perinatally
infected with HIV and 68 HIV-negative matched peers were given the
psychological tests. Fifty-five of the HIV-positive people had had an
AIDS-related condition at some point in their lives.
Participants' average age was 18.5 years. Sixty-two per cent of the HIV-positive participants and 71% of the HIV-negative peers were young women; 86% of the positive and 76% of the negative participants were of black
African ethnicity; 65% of the positive and 44% of the negative participants were born outside the UK. Three-quarters of all participants, regardless of HIV
status, were still in secondary or tertiary education.
One difference between positive and negative participants
was that 13% of the former had been fostered or adopted, versus only 2% of the
latter. This is partly explained by the fact that 44% of the positive
participants had experienced the death or one or both parents (26% of the
negative peers). Early parental loss has been shown to have an impact on cognitive development in children.
There were differences between the HIV-positive young people
who had had an AIDS-related condition and ones who had not. The former were
diagnosed at an earlier age (two years old versus six) and started antiretroviral
therapy at 3.6 years, versus 9.2 years. They were somewhat less likely to be
currently virally undetectable – 62% versus 72%. Viraemia has been
associated in some studies with neurocognitive symptoms.
Although those who had had an AIDS-related condition had
a somewhat higher current CD4 count (641 versus 555 cells/mm3), their nadir (lowest-ever) CD4 count was 166 versus
234 cells/mm3. This median (average) figure hides the fact that 25% of
them had had a CD4 nadir below 17 cells/mm3, indicating a period of profound
As previously mentioned, in the factual memory and verbal
comprehension and fluency scores, HIV-positive and negative participants both
had average Z-scores above -0.5, in other words, their scores were above the
lower one-third of results.
The HIV-negative peers' scores in these tests were not statistically different from
population-average scores and results in HIV-positive young people were still close to normal. There was a significantly
lower score in AIDS-experienced people in the verbal fluency and comprehension
scores compared to other participants (p = 0.034) but it still fell above the
lower third of results in the wider population.
The situation was different in the verbal memory, speed and
executive function test results. Here, all participants, positive and negative
alike, had test scores significantly lower that the general-population average,
with Z-scores of about -1.0 in the HIV-negative young people, -1.4 in the
general HIV-positive group, and -1.7 in the ones who had had an AIDS-related condition.
This implies average scores no higher than the lowest 16%, 10% and 5% of the
The scores of HIV negative and HIV positive young people as a
whole overlapped and were not statistically different; however the scores of
those who had had an AIDS-related condition were statistically lower than
HIV-negative participants in the verbal learning and delayed verbal memory
tests (p = 0.026 and p = 0.004 respectively).
The significantly lower performance in verbal learning and
delayed recall in young people who had ever had an AIDS-related diagnosis
suggests that profound immune suppression in people at a young age might cause subtle
neurological deficits. Dr Arenas-Pinto said that research was ongoing to find
out if these deficits persisted or corrected themselves over time.