In a study performed in Uganda, increasing levels of S100B, platelet-derived growth factor-AA, BDNF and soluble receptor for advanced glycation end products were associated with decreased odds of mild neurocognitive disorder or HIV-associated dementia.39 Novel studies reported significantly higher levels of these CSF molecules in people living without HIV with mild cognitive impairment, Alzheimer's dementia, frontotemporal dementia, and brain and spinal cord injury, suggesting a direct correlation between biomarker levels and the degree of neuronal damage.40-42. Here, BDNF is linked to Alzheimer disease.