Postural instability in individuals living with HIV infection: Relations with thalamic nuclei volumes, peripheral...

Postural stability diminishes with age, is associated with falls liability, and is disrupted in people with HIV (PWH). The thalamus, which is also affected in HIV, plays a role in balance through its reciprocal connections with cortical, subcortical, and cerebellar structures. Here, we tested postural stability in PWH and sought factors, including thalamic nuclear volumes, peripheral neuropathy, falls history, HIV-related disease, and age that may contribute to instability in PWH.

Participants included 58 PWH and 95 people without HIV (PWOH). Postural stability was assessed with the Fregly-Graybiel ataxia test battery. Volumes for nine thalamic nuclei were derived using THalamus Optimized Multi-Atlas Segmentation (THOMAS). Peripheral neuropathy, subjective pain, and number of falls were also quantified.

PWH were impaired across all postural balance tasks compared with PWOH. Poorer postural balance scores with eyes open correlated with smaller ventral posterior lateral nuclei volumes in PWH. Higher neuropathy scores in PWH correlated with poorer performance on two balance tests with eyes closed. Higher viral load was associated with greater difficulty standing on one leg with eyes closed. Even when normal aging effects were taken into account, older age in PWH related to greater difficulty standing on one leg with eyes open.

PWH consistently demonstrated balance deficits compared to PWOH, and these deficits were greater in individuals with smaller ventral thalamic nuclei. Older age, self-reported neuropathy, and measurable viral load were also associated with greater balance instability. Thus, balance instability should be monitored and PWH should be informed about balance safety as they age, especially in those who report symptoms of neuropathy or have detectable viral load.