Abstract
BACKGROUND AND AIM: Age-related macular degeneration (AMD) is the most common form of age-related visual impairment, causing central visual field loss (CFL). This leads to both reduced vision and alterations in oculomotor control, as individuals adopt eccentric viewing strategies to exploit their intact peripheral retina. Those with AMD experience mobility difficulties and greater fall risk, yet these issues remain poorly characterized, especially considering the combined effects of eccentric viewing, aging, and vision loss. Furthermore, successful fall risk interventions or rehabilitation protocols specifically aimed at improving mobility and postural control in this population are lacking.
Studies in healthy young adults have shown that gaze orientation impacts body stabilization and control. Furthermore, whole-body adaptations occur to enhance gaze/body stability during visual tasks (e.g., reading, visual search). Given that those with binocular CFL often experience more unstable gaze and compromised visual search, exploiting ecological sensorimotor relationships could offer promising rehabilitation approaches to improve both gaze and whole-body stability, potentially leading to safer environmental interactions and greater autonomy. It remains unknown, however, whether gaze-driven postural adaptations persist in older age, given age-related sensorimotor dysfunctions. To address this gap, our study is designed to include healthy-sighted young and older adults, as well as older adults with CFL.
METHODS: Preliminary data have been gathered for 9 participants (3F, age range: 31-82) including one older adult with CFL. Participants stepped in place on a force plate with and without a visual search task, their head, trunk and leg movements tracked with IMUs. Targets and distractors were projected on a screen (58°×48°) and participants reported the number of targets found during successive trials. Recordings lasted 30s and conditions were repeated 3 times.
RESULTS: Preliminary data suggest that postural adaptations driven by the demands of the search task persist in older adults with and without CFL, though there exists some variability. We observe reductions in vertical head acceleration during the search task compared to baseline, but an increase in mediolateral acceleration. Interestingly, the older adults with CFL reduced head acceleration during the search task in all planes. Head velocity increased in yaw but reduced in roll. Participants also increased step width during the search task, presumably to improve stability via a larger base of support.
CONCLUSIONS: While data collection and analysis are ongoing, we observe a preserved ability to adapt in older age. Should these observations persist in CFL, there may promising avenues for rehabilitation and training that exploit ecological relationships between sensorimotor systems.