From adolescence to old age: how sensory precision shapes body ownership during physiological aging

Isabella Martinelli^1,2Gaia Risso^1,3,4*Tommaso Bertoni⁵Valentina Meregalli⁴Enrico Collantoni^4,6Franco Molteni⁷Alessandra Pedrocchi⁸Gabriella Bottini^2,9Andrea Serino¹⁰Michela Bassolino^1,3

• ¹Institute of Health, School of Health Sciences, HES-SO Valais-Wallis, Sion, Switzerland
• ²Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
• ³The Sense Innovation & Research Center, Sion and Lausanne, Switzerland
• ⁴Department of Neurosciences, University of Padua, Padova, Italy
• ⁵MySpace Lab, Department of Clinical Neurosciences, Lausanne University Hospital, University of Lausanne, Lausanne, Switzerland
• ⁶Padua Neuroscience Center, University of Padua, Padova, Italy
• ⁷Villa Beretta Rehabilitation Center, Valduce Hospital Como, Costa Masnaga, Italy
• ⁸Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy
• ⁹Cognitive Neuropsychology Center, ASST Grande Ospedale Metropolitano Niguarda, Milan, Italy
• ¹⁰MySpace Lab, Department of Clinical Neurosciences, University Hospital Lausanne (CHUV), Lausanne, Switzerland

Body ownership relies on the integration of multisensory signals coming from the environment and the body itself. Considering the substantial neurophysiological and sensory modifications occurring across the lifespan, this study aims to quantitatively evaluate age-related changes in hand ownership and its underlying sensory and cognitive components from adolescence to advanced aging. Ninety-two healthy women aged 15-83 underwent a virtual-reality based visuo-proprioceptive disparity task in which they performed reiterative reaching movements towards visual targets while observing a virtual-hand that could be spatially congruent or displaced at different disparities from the real hand’s position. Ownership was assessed by collecting reaching errors (implicit) and asking ownership judgments toward the virtual-hand (explicit). Errors were modelled using a Bayesian Causal Inference model in which ownership for the virtual-hand resulted from a weighted average between pure visual and pure proprioceptive guidance according to their relative precision, and to the a priori probability that the virtual-hand was one’s own (prior). Results showed that both explicit and implicit ownership towards spatially incongruent virtual-hands was higher with advancing age. Moreover, the sensory components extracted from the model revealed higher proprioceptive and lower visual variability in older adults, suggesting that as proprioception declines, visual input increasingly assumes a dominant role. No age-effect was found on the prior (i.e., top-down component). We concluded that ownership progressively changes from adolescence to old age, mostly driven by a physiological reduction in proprioceptive abilities. The sensory recalibration toward visual reliance might reflect a compensatory mechanism to maintain coherent body ownership despite age-related sensory decline.