Despite active antiretroviral treatment, HIV-infected children are at risk for neurocognitive disorders and neurodevelopmental delay. This is a devastating consequence of HIV infection, with lifelong ramifications and disability. Detecting incipient neurocognitive and neurodevelopmental problems is challenging, particularly in the developing world where most pediatric HIV cases exist. Neurocognitive and neurodevelopmental test batteries take considerable time to administer (approximately 2 hours), require trained personnel, and depend on accurate normative data for interpretation. This makes them difficult to employ in the developing world where clinician time is limited, few trained personnel are available, and normative data often do not exist. In our work in both Tanzania and China, we have shown that central auditory tests can provide a ?window? into central nervous system function in HIV+ individuals. We have shown a strong negative relationship between cognitive performance and the ability to understand speech in background noise in HIV+ individuals (despite otherwise normal hearing determined by audiometric thresholds). Central auditory tests such as gap detection, the frequency following response (FFR), and interpreting speech in noise are demanding central nervous tasks involving multiple brain areas. The use of central auditory tests to assess neurocognitive function could be a major advance for screening. Speech-in-noise testing is easy for most individuals to understand, takes 10 minutes, and has existing normative data. We have performed some types of speech-in-noise testing in children as young as 6 years. The FFR is particularly promising for use with children. This test requires no input from the subject, can be done in subjects of any age, and may predict future language development. The objective for this project is to relate performance on central auditory tests to established measures of neurocognitive performance, behavior, and literacy in a cross-sectional study, and then follow the children in a longitudinal study to assess the ability of the central auditory tests to predict future function?particularly language development. The appropriate use of these tests to screen for neurocognitive problems will be established through the analysis of the receiver operating characteristic curves taking into account the effects of confounders. We have assembled an international team with experience in central auditory testing and neurocognitive and neurodevelopmental testing in HIV + individuals. Dr. Nina Kraus and her team at Northwestern are internationally-recognized experts in the auditory FFR. The team in Dar es Salaam has extensive experience in performing both central auditory and neurocognitive tests. Dr. Jonathan Lichtenstein in collaboration with Dr. Michael Boivin are expert in assessing neurocognitive function and developmental delay in children. Together this team will be able to determine the role central auditory testing could play in assessing children in the developing world with HIV. These tests may offer a new and improved way to assess the central nervous system co-morbidities of HIV infection in resource-limited settings.
This study will show whether central auditory tests could offer a valuable assessment for the central nervous system effects of HIV infection in children. Diagnosing and monitoring of central nervous system co- morbidities is essential in HIV infection, and central auditory tests may offer a simpler, easier to perform way to assess this than current techniques. This could alter clinical practice if central auditory tests can shown to be useful for screening for or tracking central nervous system effects in HIV+ children in resource-limited settings.
