The degradation of the sense of touch (e.g. due to aging) on the bottom of our feet can compromise balance, leading to an increased risk for falls. Our project aims to build a shoe insole that uses passive, sub-sensory mechanical vibrations to enhance somatosensation in the feet. Such a system could thereby theorectically improve sensory information critical to maintenance of upright balance.
As background, it has previously been shown that actively generated vibrating insoles can improve balance in the elderly. The underlying phenomenon is termed 'stochastic resonance', in which sub-sensory noise acts to reduce sensory thresholds needed to detect plantar sensation. Although clinical studies suggest this is theoretically viable assistive technology, current insole designs are active and thus reliant on batteries and actuators. Active devices are not easily fit into a shoe and require periodic recharging. The complexity, cost and maintenance of this implementation may limit the widespread use of the technology.
It is well recognized that we dissipate energy in each heel strike. Thus, we propose that it theoretically possible that a vibrating insole could potentially be powered by passively harvesting energy during walking. Thus, this project involves designing a shoe insole with a completely passive vibration mechanism. The system should be low-cost, simple and shown to generate sub-sensory, stochastic noise in the insole. Some pilot testing on human subjects walking with the insoles will be performed in the UW Neuromuscular Biomechanics Lab to assess comfort and affect on balance.
- Joseph Ashley - Team Leader & BSAC
- Anna Tessling - Communicator
- Madeline Honke - BWIG
- Alli Abolarin - BPAG