PROJECT SUMMARY/ABSTRACT
Since the introduction of successful treatment for human immunodeficiency virus (HIV) via antiretroviral therapy
(ART), individuals infected with HIV are now living longer with estimates that in the United States over half of all
HIV infected individuals and in California 67 percent of people living with HIV (PLWH) are over the age of 50.
Due to this major demographic shift in the HIV-infected population in the US, and as outlined in PA-20-149, there
is an urgent need to better define the underlying pathophysiology of neurological complications and
neurocognitive decline in the aging HIV-infected populations. Despite ART treatment, HIV-associated
neurocognitive disorders (HAND) occur with high heterogeneity in the pattern and severity of deficits, particularly
in people aging on modern ART regimens. Our research points to neuroimaging biomarkers that could be of
advantage for identifying diagnostic signatures and understanding the heterogeneity of CNS disease in relation to
behavioral manifestations, that would need to be followed up with longitudinal research. Bradyphrenia was
indicative of worse performance in other cognitive domains, mediated by basal ganglia-limbic brain pathway
compromise, and related to bradykinesia, a main symptom in age-related neurodegeneration in Parkinson's
disease (PD). Bradykinesia occurred in PLWH with more severe cognitive impairment and could be a sign of
disease progression involving more widespread brain networks. Our novel application of fMRI-derived amplitudes
of low frequency fluctuations (ALFF) indicated disrupted neurodynamics in subcortico-cortical circuits in older
PLWH, with some overlap with the pathophysiology in PD8. Our research points to predictors of the interindividual
variation in impairment profiles related to past HIV severity (nadir CD4, AIDS), current CD4 count, older age, alcohol
and substance use, and sleep quality as a measure of resilience. Here, we extend this work in direct response to
PA-20-149, aiming to longitudinally investigate the neurocognitive profile using the NIMH's Research Domain
Criteria (RDoC) framework to evaluate previously identified neuroimaging biomarkers of cognitive and motor
deficits in aviremic older PLWH on ART. We focus on the role of bradyphrenia and bradykinesia for the discovery
of neuroimaging biomarkers for CNS disease progression by following our established study cohorts and new
recruits of older PLWH, Parkinson's disease (PD), and age-matched healthy controls (HC).
The specific aims of this proposal are to
Aim 1: Identify neuroimaging biomarkers for worsening in cognition using a domain-based approach.
Aim 2: Determine the role of subclinical parkinsonism for later impairment in PLWH, and similarities to PD.
Aim 3: Seek modifiable risk factors and moderators for disease progression in PLWH.