3D-printed foot orthoses with customized somatosensory stimulation knobs enhance balance and stability in older adults

Age-related declines in plantar sensitivity contribute to balance deficits in older adults, motivating the use of somatosensory stimulation foot orthoses (SSFO) to enhance sensory input. This study evaluated the effects of 3D-printed SSFO with customized knob heights on postural control in older adults using computerized dynamic posturography. In a randomized, controlled, parallel-group study with a within-subjects component, 46 community-dwelling adults aged over 65 years were assigned to either a control group receiving flat foot orthoses (FFO) or an intervention group receiving both SSFO and placebo foot orthoses (PFO). SSFO and PFO were 3D-printed and individually customized. Postural stability and control were assessed using the Sensory Organization Test, Motor Control Test, and Adaptation Test. Compared to PFO, SSFO significantly improved equilibrium scores during eyes-open trials on a fixed support surface (p = 0.028). SSFO significantly increased weight symmetry compared to FFO (medium-magnitude-backward translation: p = 0.050) and PFO (large-magnitude-forward translation: p = 0.033), and response latency compared to FFO (medium-magnitude-backward translation: p = 0.033; large-magnitude-forward translation: p = 0.035). SSFO significantly reduced sway energy during toes-up perturbations compared to FFO (p = 0.018) and toes-down perturbations compared to PFO (p = 0.043). 3D-printed SSFO enhanced somatosensory feedback and improved postural stability but increased response latency. Further research is warranted to investigate SSFO's broader clinical application.