Data-Driven Clustering of Plantar Thermal Patterns in Healthy Individuals: An Insole-Based Approach to Foot Health Monitoring

Monitoring plantar foot temperatures is essential for assessing foot health, particularly in individuals with diabetes at increased risk of complications. Traditional thermographic imaging measures foot temperatures in unshod individuals lying down, which may not reflect thermal characteristics of f...

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Main Authors: Mark Borg, Stephen Mizzi, Robert Farrugia, Tiziana Mifsud, Anabelle Mizzi, Josef Bajada, Owen Falzon
Format: Article
Language:English
Published: MDPI AG 2025-02-01
Series:Bioengineering
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Online Access:https://www.mdpi.com/2306-5354/12/2/143
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author Mark Borg
Stephen Mizzi
Robert Farrugia
Tiziana Mifsud
Anabelle Mizzi
Josef Bajada
Owen Falzon
author_facet Mark Borg
Stephen Mizzi
Robert Farrugia
Tiziana Mifsud
Anabelle Mizzi
Josef Bajada
Owen Falzon
author_sort Mark Borg
collection DOAJ
description Monitoring plantar foot temperatures is essential for assessing foot health, particularly in individuals with diabetes at increased risk of complications. Traditional thermographic imaging measures foot temperatures in unshod individuals lying down, which may not reflect thermal characteristics of feet in shod, active, real-world conditions. These controlled settings limit understanding of dynamic foot temperatures during daily activities. Recent advancements in wearable technology, such as insole-based sensors, overcome these limitations by enabling continuous temperature monitoring. This study leverages a data-driven clustering approach, independent of pre-selected foot regions or models like the angiosome concept, to explore normative thermal patterns in shod feet with insole-based sensors. Data were collected from 27 healthy participants using insoles embedded with 21 temperature sensors. The data were analysed using clustering algorithms, including k-means, fuzzy c-means, OPTICS, and hierarchical clustering. The clustering algorithms showed a high degree of similarity, with variations primarily influenced by clustering granularity. Six primary thermal patterns were identified, with the “butterfly pattern” (elevated medial arch temperatures) predominant, representing 51.5% of the dataset, aligning with findings in thermographic studies. Other patterns, like the “medial arch + metatarsal area” pattern, were also observed, highlighting diverse yet consistent thermal distributions. This study shows that while normative thermal patterns observed in thermographic imaging are reflected in insole data, the temperature distribution within the shoe may better represent foot behaviour during everyday activities, particularly when enclosed in a shoe. Unlike thermal imaging, the proposed in-shoe system offers the potential to capture dynamic thermal variations during ambulatory activities, enabling richer insights into foot health in real-world conditions.
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spelling doaj-art-86f5c1d6ca91484db2a6ca797b6a36022025-08-20T03:11:58ZengMDPI AGBioengineering2306-53542025-02-0112214310.3390/bioengineering12020143Data-Driven Clustering of Plantar Thermal Patterns in Healthy Individuals: An Insole-Based Approach to Foot Health MonitoringMark Borg0Stephen Mizzi1Robert Farrugia2Tiziana Mifsud3Anabelle Mizzi4Josef Bajada5Owen Falzon6Centre for Biomedical Cybernetics, University of Malta, MSD 2080 Msida, MaltaDepartment of Podiatry, Faculty of Health Sciences, University of Malta, MSD 2080 Msida, MaltaDepartment of Podiatry, Faculty of Health Sciences, University of Malta, MSD 2080 Msida, MaltaDepartment of Podiatry, Faculty of Health Sciences, University of Malta, MSD 2080 Msida, MaltaDepartment of Podiatry, Faculty of Health Sciences, University of Malta, MSD 2080 Msida, MaltaDepartment of AI, Faculty of ICT, University of Malta, MSD 2080 Msida, MaltaCentre for Biomedical Cybernetics, University of Malta, MSD 2080 Msida, MaltaMonitoring plantar foot temperatures is essential for assessing foot health, particularly in individuals with diabetes at increased risk of complications. Traditional thermographic imaging measures foot temperatures in unshod individuals lying down, which may not reflect thermal characteristics of feet in shod, active, real-world conditions. These controlled settings limit understanding of dynamic foot temperatures during daily activities. Recent advancements in wearable technology, such as insole-based sensors, overcome these limitations by enabling continuous temperature monitoring. This study leverages a data-driven clustering approach, independent of pre-selected foot regions or models like the angiosome concept, to explore normative thermal patterns in shod feet with insole-based sensors. Data were collected from 27 healthy participants using insoles embedded with 21 temperature sensors. The data were analysed using clustering algorithms, including k-means, fuzzy c-means, OPTICS, and hierarchical clustering. The clustering algorithms showed a high degree of similarity, with variations primarily influenced by clustering granularity. Six primary thermal patterns were identified, with the “butterfly pattern” (elevated medial arch temperatures) predominant, representing 51.5% of the dataset, aligning with findings in thermographic studies. Other patterns, like the “medial arch + metatarsal area” pattern, were also observed, highlighting diverse yet consistent thermal distributions. This study shows that while normative thermal patterns observed in thermographic imaging are reflected in insole data, the temperature distribution within the shoe may better represent foot behaviour during everyday activities, particularly when enclosed in a shoe. Unlike thermal imaging, the proposed in-shoe system offers the potential to capture dynamic thermal variations during ambulatory activities, enabling richer insights into foot health in real-world conditions.https://www.mdpi.com/2306-5354/12/2/143wearable sensorssmart insolesfoot health monitoringplantar thermal patternsthermal mapsdata-driven clustering
spellingShingle Mark Borg
Stephen Mizzi
Robert Farrugia
Tiziana Mifsud
Anabelle Mizzi
Josef Bajada
Owen Falzon
Data-Driven Clustering of Plantar Thermal Patterns in Healthy Individuals: An Insole-Based Approach to Foot Health Monitoring
Bioengineering
wearable sensors
smart insoles
foot health monitoring
plantar thermal patterns
thermal maps
data-driven clustering
title Data-Driven Clustering of Plantar Thermal Patterns in Healthy Individuals: An Insole-Based Approach to Foot Health Monitoring
title_full Data-Driven Clustering of Plantar Thermal Patterns in Healthy Individuals: An Insole-Based Approach to Foot Health Monitoring
title_fullStr Data-Driven Clustering of Plantar Thermal Patterns in Healthy Individuals: An Insole-Based Approach to Foot Health Monitoring
title_full_unstemmed Data-Driven Clustering of Plantar Thermal Patterns in Healthy Individuals: An Insole-Based Approach to Foot Health Monitoring
title_short Data-Driven Clustering of Plantar Thermal Patterns in Healthy Individuals: An Insole-Based Approach to Foot Health Monitoring
title_sort data driven clustering of plantar thermal patterns in healthy individuals an insole based approach to foot health monitoring
topic wearable sensors
smart insoles
foot health monitoring
plantar thermal patterns
thermal maps
data-driven clustering
url https://www.mdpi.com/2306-5354/12/2/143
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