SBIR-STTR Award

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 the tactile system in diabetics is known to have significant clinical sequelae including gait abnormalities, propensity to fall, and foot ulcers. Diabetic peripheral neuropathy, with its complications, costs the U.S. healthcare system many billions of dollars annually. The goal of the proposed research is to advance early laboratory results toward a therapeutic device for enhancing the tactile sense in diabetic patients. The work will demonstrate the ability of mechanical stimulation to improve sensitivity using two metrics. First, we will determine the magnitude of the SR benefit in diabetics using standard neurological examinations, specifically the Semmes-Weinstein and vibration perception threshold tests. Second, we will explore the functional benefit of mechanical stimulation in stance and sway experiments. Both experiments will give a measure of true functional benefit. PROPOSED COMMERCIAL APPLICATIONS: If successful, the proposed research will lead to medical devices that improve tactile sensitivity in people who suffer from diabetic peripheral neuropathy. This would improve quality of life for these individuals while reducing the costs of caring for them. Additional medical applications include use of technology in stroke, aging, and rehabilitation medicine

More than 10 million individuals in the U.S. are thought to suffer from diabetic neuropathies. Many serious medical problems stem from this condition, including degradation of the mechanical senses of touch and proprioception. Usually affecting the extremities first and most severely, the progressive loss of sensory function is a leading precursor to the formation of dangerous skin ulcers. For 80,000 Americans each year, the only treatment is partial or complete amputation of the affected extremity. Afferent is working to develop an innovative non-invasive neurotherapeutic medical device that directly and immediately improves mechanical sensation in the feet and lower extremities of neuropathic diabetics with. By effectively "turning up the volume" of sensory information, our aim is to create products that increase the mobility of these individuals while decreasing the likelihood that they will experience skin ulceration. The technology is based on the well-established finding that low-level stimulation applied to sensory receptors improves their sensitivity and raises the information content of their firing patterns. In our Phase I SBIR program, people with sensory loss secondary to diabetes showed significantly improved detection of plantar stimuli when small-amplitude mechanical vibratory stimulation was delivered to the foot sole. This was measured using traditional clinical neurological techniques. Mechanical foot sole stimulation also improved measures of quiet standing balance in diabetic subjects. The proposed program will focus first on significantly advancing the design and performance of product prototypes. These new devices will then be tested on diabetic subjects to demonstrate efficacy at two levels: 1) localized improvement in tactile sensitivity measured using traditional neurological exams, and 2) system-level improvement in the biomechanics of dynamic balance and gait, as measured by plantar pressure distribution, tissue perfusion, and kinematics. Instruments and methods that can be used to optimize benefit for individuals, e.g. on the basis of the interplay between stimulation parameters and severity of the neuropathy, will also be developed. Results of this work will form the basis for undertaking a full-fledged product development effort, pivotal clinical trials, regulatory filings, and market introduction.

Thesaurus Terms:
biomedical equipment development, diabetic neuropathy, neuromuscular stimulator, noise, touch diabetes mellitus, motion perception, proprioception /kinesthesia, skin ulcer clinical research, human subject, neuropsychological test