# Aging and sensory contributions to spatial orientation > **NIH NIH K02** · JOHNS HOPKINS UNIVERSITY · 2024 · $149,880 ## Abstract Spatial perception is based on various sensory inputs processed within a widely-distributed cerebral network. Cur- rently it is not known how these multisensory mechanisms and their contributions to spatial orientation are affected by aging. Clinical histories in elderly frequently entail experiences of spatial misperceptions with sudden feelings of imbalance or tilt that can lead to injuries that are highly morbid and costly. Here we combine psychophysics and mathematical modelling to investigate age-related changes in these ‘high order’ mechanisms. We have studied spatial orientation in the context of Bayesian spatial model (BSM), which incorporates the sensory signals that encode the head and eye positions to quantify perceived upright orientation. Accordingly, the signal-to-noise ratio in each sensory modality affects its reliability for integration into an internal (i.e., neural) estimate that contributes to spatial orientation. In this novel approach, sensory contributions are measured directly in psychophysical para- digms. In this proposal, we apply the same approach within the quantitative BSM framework to study changes in spatial orientation with aging. We’ve found individuals with vestibular loss have a bias in spatial orientation related to underestimation of their head position. With aging, there is also sensory loss in the vestibular system that can lead to problems with balance and spatial orientation by affecting how the brain reweights sensory information to compensate for such changes. This reweighting process is important to understand for devising diagnostic tools and rehabilitation/treatment programs preferably at the individual subject level. On this basis, our central hypothesis is that in the process of sensory integration for spatial orientation, older individuals underestimate their eye and head positions, resulting in larger errors of spatial orientation and more postural instability compared with younger individuals. To test this hypothesis, we (i) parse out sensory contributions to spatial orientation in aging, and (ii) examine whether they correspond with age-related vestibular physiologic changes and fall risk. A key vestibular input is from the otoliths that contributes to wide range of neurophysiologic functions such as sensing the head motion with respect to gravity and it also drives the vestibulo-ocular response known as the ocular counter roll (OCR). We have developed a video-oculography measure of OCR (vOCR), which is done with a simple tilt maneu- ver. Here we also examine whether vOCR can be used as a biomarker of age-related changes in spatial orientation, postural stability, and fall risk. Overall, this approach gives us a unique opportunity to apply our current research work towards elucidating sensory contributions to changes in spatial orientation with aging. The key developments in this proposal are identifying distinct changes in spatial orientation and examining a clinical measure of otolith functio... ## Key facts - **NIH application ID:** 10808228 - **Project number:** 1K02AG083134-01A1 - **Recipient organization:** JOHNS HOPKINS UNIVERSITY - **Principal Investigator:** Amir Kheradmand - **Activity code:** K02 (R01, R21, SBIR, etc.) - **Funding institute:** NIH - **Fiscal year:** 2024 - **Award amount:** $149,880 - **Award type:** 1 - **Project period:** 2024-09-01 → 2027-05-31 ## Primary source NIH RePORTER: https://reporter.nih.gov/project-details/10808228 ## Citation > US National Institutes of Health, RePORTER application 10808228, Aging and sensory contributions to spatial orientation (1K02AG083134-01A1). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10808228. Licensed CC0. --- *[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*