Convergent and divergent oscillatory aberrations during visuospatial processing in HIV-related cognitive impairment and Alzheimer's disease

Adults with HIV frequently develop a form of mild cognitive impairment known as HIV-associated neurocognitive disorder (HAND), but presumably cognitive decline in older persons with HIV could also be attributable to Alzheimer's disease (AD). However, distinguishing these two conditions in individual patients is exceedingly difficult, as the distinct neural and neuropsychological features are poorly understood and most studies to date have only investigated HAND or AD spectrum (ADS) disorders in isolation. The current study examined the neural dynamics underlying visuospatial processing using magnetoencephalography (MEG) in 31 biomarker-confirmed patients on the ADS, 26 older participants who met criteria for HAND, and 31 older cognitively normal controls. MEG data were examined in the time-frequency domain, and a data-driven approach was utilized to identify the neural dynamics underlying visuospatial processing. Both clinical groups (ADS/HAND) were significantly less accurate than controls on the task and exhibited stronger prefrontal theta oscillations compared to controls. Regarding disease-specific alterations, those with HAND exhibited stronger alpha oscillations than those on the ADS in frontoparietal and temporal cortices. These results indicate both common and unique neurophysiological alterations among those with ADS disorders and HAND in regions serving visuospatial processing and suggest the underlying neuropathological features are at least partially distinct.