Alterations in the hemodynamic response function in cognitively impaired HIV/AIDS subjects

Area of Science:

• Neuroimaging
• Neuroscience
• Infectious Diseases

Background:

• Functional magnetic resonance imaging (fMRI) is crucial for understanding Central Nervous System (CNS) alterations in HIV/AIDS.
• Assessing the blood oxygen level dependent hemodynamic response function (BOLD HRF) is a prerequisite for advanced cognitive fMRI studies in this population.

Purpose of the Study:

• To compare BOLD HRF signals between HIV/AIDS patients and control subjects.
• To establish the BOLD HRF as a baseline measure for cognitive function studies in HIV/AIDS.

Main Methods:

• Event-related fMRI was employed to measure BOLD HRF in the precentral gyrus during a sensory-motor task.
• Subjects were categorized into control, Normal/Asymptomatic Neuropsychological Impairment (ANI), and Minor Neurocognitive Disorder (MNCD)/HIV-Associated Dementia (HAD) groups.

Main Results:

• No significant differences in BOLD HRF were observed based on age, hemisphere, or HIV serostatus alone.
• MNCD/HAD subjects exhibited a BOLD HRF that did not return to baseline within 16 seconds.
• This prolonged HRF in MNCD/HAD subjects suggests potential alterations in neuronal function.

Conclusions:

• Subtle alterations in neuronal function, indicated by prolonged BOLD HRF, are present in HIV/AIDS patients with significant cognitive impairment (MNCD/HAD).
• These findings highlight potential challenges for event-related fMRI studies in this specific patient subgroup.
• Further research is needed to understand the full implications of these neurophysiological changes for cognitive assessment using fMRI.