Reduced Motor Individuality in Older Adults Revealed by Network-Based Gait Fingerprinting.

Background and Objectives: Gait is a fundamental human behavior essential for individual autonomy and well-being; it reflects a complex inter-joint coordination that can change with aging. Materials and Methods: This study applied a network-based fingerprinting approach to evaluate the stability and individuality of gait coordination in adults (mean age: 41.6) and older adults (mean age: 73.5). Each participant completed two gait recordings, from which we constructed kinematic networks (i.e., kinectome) representing joint-velocity correlations. Then, borrowing from network fingerprinting techniques, we computed measures of intra-subject similarity (Iself), inter-subject similarity within the same group (Iothers), cross-group similarity (Iextra), and individual discriminability (Differentiation rate, DR). Results: While Iself was comparable across groups, older adults showed higher Iothers and lower DR, indicating more homogeneous and less distinctive coordination patterns. Furthermore, Iothers was significantly higher than Iextra in the older group only, suggesting age-specific convergence in motor behavior. Conclusions: These findings support the hypothesis that aging reduces the individuality of gait coordination, possibly due to adaptive or degenerative changes in motor control. Kinectome-based fingerprinting thus offers a promising tool for capturing subtle shifts in neuromotor organizations linked to aging.