Could New Wearable Technologies Help Replace Lost Or Impaired Plantar Pressure Proprioception?

Assessing The Potential Of Insoles And Sensory Substitution For Patients With Diabetes

Orpyx's SurroGait Rx™ was recently mentioned in Volume 29 - Issue 3 - March 2016 of Podiatry TodayPodiatry Today is an award-winning, premier publication that emphasizes informative clinical features and columns as well as practice management articles. The authors Dr. Breanne Everett - Orpyx's CEO and Co-Founder, Dr. Asmussen, and Dr. Armstrong discuss changing perspectives on neuroplasticity and the evolution of sensory substitution, and how these trends have led to wearable technology with potential benefits in this high-risk population. 

The SurroGait Rx™ Sensory Substitution System may improve gait and balance in individuals with reduced or absent plantar pressure sensation. With lost sensation in the feet, it becomes difficult to detect changes in posture. This ultimately impacts a person’s ability to stand or walk. SurroGait Rx technology effectively replaces the lost or impaired plantar pressure proprioception with a new type of sensory input.

The SurroGait Rx was designed to help people with impaired foot sensation to be aware of their base of support limits. The SurroGait Rx functions by placing pressure sensing insoles in the shoes of patients to detect when they are approaching the limits of their base of support. Similar to how the “rumble strips” inform people about where they are in their own lane while driving, the SurroGait Rx uses information from the pressure sensing insoles to tell people about their base of support via vibrations from a vest worn on the back.

Research has shown that the SurroGait Rx has beneficial effects on gait and posture control in individuals with peripheral neuropathy. In a small scale clinical trial, researchers sought to determine if there were changes in measures of gait and balance control after patients used the SurroGait Rx device for an extended period of time. Specifically, researchers obtained baseline gait and balance control measures from 10 patients with peripheral neuropathy before wearing the SurroGait Rx device for four weeks. These baseline measures included 1) center of pressure path length to assess balance, 2) spatial/temporal stride and step characteristics to determine gait kinematic differences and 3) kinetic variable of gait.

In terms of balance control, patients with peripheral neuropathy showed less sway when balancing with their eyes closed, suggesting improved balance control. These changes occurred because of the demand to incorporate somatosensory input to guide balance control in the absence of vision. Given that patients with peripheral neuropathy already have compromised plantar pressure proprioception, they likely relied on the vibrotactile inputs from the SurroGait Rx device to improve their perception of their swaying body and accordingly improved their balance.

In terms of gait measures, the SurroGait Rx device also shows beneficial effects. When wearing the device, patients with peripheral neuropathy had increased stride frequency (i.e., more steps taken over a fixed distance) and  reduced variability of stride frequency (i.e., keeping the number of steps taken over a fixed distance consistent). Overall, the evidence suggests there is a positive benefit of the SurroGait Rx for patients with peripheral neuropathy in the form of immediate improvements in gait and balance.

Outside of direct sensory substitution-based feedback, there is also a role to play for cue-based feedback to patients with diabetic peripheral neuropathy. Another technology, the SurroSense Rx™ smart insole system does this by providing offloading and activity guidance based on data collected in a pressure sensitive insole. While the product’s impact with respect to gait and balance is less pronounced, the simplicity of the system - with its inconspicuousness and potential ease of deployment - provides a high degree of promise in its own right.

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Chan Mean
Chan Mean

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