Dr. Thomas Legrand watched the brain scans light up differently as his older study participants struggled to keep their balance on a foam block. What he was seeing—older brains working nearly 50% longer to process the same balancing task—suggested a fundamental shift in how aging changes not just the body, but the mind's ability to keep us upright.
The discovery matters because falls are a leading cause of injury among older adults, yet scientists have largely understood aging's impact on balance through indirect methods: asking people to perform mental tasks while walking, or simply observing their wobble. Legrand and his international team—including researchers from the UCD School of Electrical and Electronic Engineering and the ULB Neuroscience Institute—took a more direct approach. They recorded brain activity in roughly 60 adults under 30 and 60 adults over 65 as participants stood on either solid ground or a foam block, with eyes open or closed. Each participant also underwent an assessment of their vestibular system, the sensory network in the inner ear that controls balance and spatial orientation.
The results, published in the Proceedings of the National Academy of Sciences, revealed something striking: older adults' brain activity synced closely with how much they wobbled, especially in challenging balance situations. Those who wobbled most showed the highest brain activity—a sign that their brains were working overtime to stay upright. Younger people, by contrast, maintained balance automatically, without conscious effort or mental strain.
"This means that older adults have to actively maintain their balance, using parts of their brain to stay upright," Legrand explained. "Younger people, on the other hand, stay balanced automatically without having to think about it or use up mental energy." Beyond the increased effort, older brains also needed significantly more time to process balance information—a delay of almost 50% compared to younger adults.
What makes this finding particularly significant is what it rules out. Many of the older participants showed evidence of inner-ear decline, yet this wasn't the reason their brains were working so much harder. The culprit wasn't peripheral; it was central. The aging brain itself had shifted how it manages balance, requiring greater cognitive resources to accomplish what younger brains handle effortlessly.
This understanding opens a path forward. Falls among older adults carry serious consequences—broken hips, head injuries, loss of independence—yet most fall-prevention strategies focus on physical strength or environmental hazards. The research suggests that brain-based interventions might help. If scientists can understand which brain regions older adults recruit for balance, and how the processing delay develops, they could potentially design treatments or therapies to strengthen those neural pathways or speed up processing.
For Legrand and his colleagues, the work represents a foundation. "This research helps us understand how the aging brain controls balance, and it opens the door for future studies in medicine and neuroscience to help predict and hopefully prevent fall risks in older adults," he said. That's the promise of this work: not just explaining why older adults fall more often, but equipping researchers with the knowledge to help prevent those falls in the first place.