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Patterns of relative cerebral blood flow in minor cognitive motor disorder in human immunodeficiency virus infection
M B Wiseman1, J A Sanchez, C Buechel
1Neuropsychology Research Program, University of Pittsburgh Medical Center, Pennsylvania, USA.
Abstract:
Individuals infected with HIV are at risk to develop cognitive impairment during the course of their disease. Although many patients develop an HIV-associated dementia, others may develop the less severe minor cognitive motor disorder (MCMD). In this study, relative cerebral blood flow was measured with PET imaging in HIV+ MCMD patients, HIV+ control subjects, and HIV- control subjects; analyses were performed by using statistical parametric mapping. Comparing a short-term memory task versus a rest state yielded activation in superior temporal cortex, postcentral gyrus, and cerebellum in all three subject groups. Comparing long- and short-term memory tasks yielded activation throughout the frontal cortex, including BA46. Activation in this area was reduced in the HIV+ control subjects and further reduced in the MCMD+ patients. Thus, brain activation associated with lower-level, automatic processing appears normal in HIV+ MCMD+ subjects, but activation associated with effortful retrieval and organizational processes is abnormal.
Insights
HIV infection can impair cognitive function. This study found that individuals with HIV-associated minor cognitive motor disorder (MCMD) show abnormal brain activation during effortful memory tasks, unlike basic processing.
Area of Science:
- Neuroscience
- Infectious Diseases
- Cognitive Science
Background:
- Human Immunodeficiency Virus (HIV) infection is associated with cognitive impairment.
- While some patients develop HIV-associated dementia, others experience milder cognitive deficits like minor cognitive motor disorder (MCMD).
- Understanding the neural correlates of cognitive dysfunction in HIV is crucial for targeted interventions.
Purpose of the Study:
- To investigate differences in brain activation patterns between HIV-positive individuals with MCMD, HIV-positive controls, and HIV-negative controls.
- To identify specific cognitive processes affected by HIV-associated MCMD.
Main Methods:
- Positron Emission Tomography (PET) imaging was used to measure relative cerebral blood flow.
- Statistical Parametric Mapping (SPM) was employed for data analysis.
- Participants performed memory tasks and a rest state.
Main Results:
- All subject groups showed normal brain activation in the superior temporal cortex, postcentral gyrus, and cerebellum during a short-term memory task.
- Activation in the frontal cortex, including BA46, during a long-term memory task was reduced in HIV-positive controls compared to HIV-negative controls.
- This frontal cortex activation was further reduced in HIV-positive MCMD patients.
Conclusions:
- Brain activation related to automatic, lower-level cognitive processing appears intact in HIV+ MCMD subjects.
- Effortful memory retrieval and organizational cognitive processes are impaired in HIV+ MCMD patients, as evidenced by reduced frontal cortex activation.
- These findings highlight specific cognitive deficits in HIV-associated MCMD and suggest potential targets for therapeutic strategies.