Innovative single-sensor, in-shoe pressure and temperature monitoring device : a static laboratory validation study

Abstract

Background: To perform laboratory static validation of pressures from an innovative, single-sensor pressure and temperature monitoring device for the early detection of complications in the high-risk foot.

Research question: Can an innovative, newly developed, in-shoe pressure and temperature measuring device, detect and measure the in-shoe peak plantar pressures and skin temperature as accurately as the reference standard?

Methods: A pressure generating rig, the Tekscan™ Equilibration ‘bladder calibrator’, was used to produce a known force, against the gold standard, FScan™ in-shoe pressure mapping system by Tekscan™ and a newly developed prototype. The F-scan® system was used to record the pressure readings and establish a baseline for the readings recorded utilising the prototype. A total of 20 pressure values were recorded with 100 samples each.

Results: Exploratory data analysis was conducted to gain insights and analyse the prototype's behaviour at different pressure points. Pre-processing and data cleaning were also performed to remove any anomalies. Support Vector Regressor with a polynomial kernel and Grid-Search algorithm was used to fit the recorded data curve. The best combination of parameters had a Mean Squared Error of 2.59 and a Root Mean Squared Error of 1.61. A simple linear equation was used to convert raw readings to pressure values. Significance: The results of this study conclude that the pressure measurements taken with the prototype are congruent to the gold standard, F-scan® in-shoe system. This confirms that the prototype is a valid device that can be used safely as a low-cost alternative to current costly commercial in-shoe pressure mapping devices.