Effects of somatosensory-stimulating foot orthoses on postural balance in older adults: A computerized dynamic posturography analysis

Background: Foot orthoses (FO) with protruding knobs designed to stimulate the mechanoreceptors on the glabrous skin of the foot have been proposed to enhance proprioception, thereby improving postural balance and stability. This study aimed to investigate the effects of these FO with stimulating knobs on the postural balance in the elderly using computerized dynamic posturography (CDP). Research question: Do FO with stimulating knobs enhance postural balance in the elderly by improving scores related to sensory organization, motor control, and adaptation in response to different static and dynamic perturbation conditions? Methods: Twenty-three healthy elderly participants performed the CDP, which includes Sensory Organization Test, Motor Control Test, and Adaptation Test in both flat FO and stimulating FO. The Bertec Balance Advantage System with force plates was employed to collect comprehensive CDP data. Results: Our results indicated a significant improvement in the composite equilibrium score (MD=1.44, p = 0.048) and weight symmetry (MD=-1.85, p = 0.024) between the two limbs when using the stimulating FO compared to the flat FO condition. The latency and amplitude scaling during backward translation as well as sway energy during toes down perturbations were lower in females than males with stimulating FO (Latency: MD=-6.62, p = 0.044; Amplitude scaling: MD=-1.75, p = 0.011; Sway energy: MD=-40.08, p = 0.007). Significance: These findings highlight the potential of stimulating FO to provide enhanced somatosensory feedback for better postural control and coordination, underscoring their potential clinical application in improving balance and sensory integration.