Stochastic resonance (SR) is a counterintuitive phenomenon in which slight amounts of noise imparted to a system actually increase its sensitivity to weak stimuli. SR has been shown to produce a demonstrable effect in human sensory cells. In both healthy young and clinical subjects - elderly, diabetics, and stroke sufferers - a notable increase in tactile and proprioceptive sensitivity is seen when electrical or mechanical noise is presented at the site of the stimulus. Dysfunction in these sensory systems is known to have significant clinical sequellae including gait abnormalities, propensity to fall, and foot ulcers. Together, these conditions cost the U.S. healthcare system many billions of dollars annually. The proposed research will initiate a development program whose ultimate goal is to produce fully implantable medical devices that capitalize on this effect to treat certain types of sensory dysfunction. In an acute in-vivo animal model, we will test the hypothesis that sub- sensory noise delivered via subcutaneous electrodes placed near mechanoreceptors in the lower leg improves the ability of those receptors to discern slight rotations about the ankle. Direct recordings will be made of afferent nerve signals from those mechanoreceptors. We will also assess whether the receptors adapt to the noise stimulation, rendering it ineffective over time.
If successful, the proposed research can lead to implantable medical devices that improve somatosensory sensitivity in people who suffer from peripheral neuropathy. This would improve quality of life for these individuals while reducing the costs of caring for them. Applications include uses in improving gait and balance, some forms of incontinence, and rehabilitation medicine.
