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TECHNOLOGY AND CODE article

Front. Digit. Health

Sec. Health Informatics

Volume 7 - 2025 | doi: 10.3389/fdgth.2025.1576031

This article is part of the Research TopicIntelligent Rehabilitation Technology Incorporating Multimodal Information Feedback and StimulationView all 3 articles

Assessment of shoulder functional movements through Inertial Measurement Units for tele-rehabilitation: a quaternion-based approach

Provisionally accepted
Matteo  IuratoMatteo Iurato1,2*Paolo  DonderoPaolo Dondero2Mirko  JobMirko Job1Ronny  StanzaniRonny Stanzani2Gaia  LeuzziGaia Leuzzi1,3Igor  IngegnosiIgor Ingegnosi2Marco  TestaMarco Testa1
  • 1University of Genoa, Genoa, Italy
  • 2Swhard s.r.l., Genova, Italy
  • 3Vrije University Brussels, Brussels, Brussels, Belgium

The final, formatted version of the article will be published soon.

Telerehabilitation improves accessibility and accelerates recovery: in this context, Inertial Measurement Units (IMUs) are promising wearable sensors for remote movement data collection, which allows to evaluate how closely exercise repetitions align with a prescribed trajectory. Current data processing methods for this purpose include data-driven approaches, requiring exercise-specific training through large amount of data, or distance-based methods with unbounded output, not easy to interpret. This study proposes a novel algorithm which combines the versatility of a bounded output score with numerical stability of quaternions. Data from an IMU-based device were acquired during the execution of human functional shoulder movements by both a young and elderly group of participants. Outputs from the application of the proposed methodology on collected data from same or different movements were statistically compared, revealing ability of discriminating repetitions of the same or of different movements (p < 0.01, rrb effect size = 0.97, contrast ratio 1.7). The proposed algorithm was also confronted with the traditional approaches by statistically comparing outputs from comparison matrices rescaled in equal range of values, and results indicated mild differences in performance (rrb effect size < 0.5). Future works may involve integrating this approach into a functioning telerehabilitation system and obtaining feedback on the usability from real users.

Keywords: IMU, Movement assessment, quaternions, rehabilitation exercises, Shoulder

Received: 13 Feb 2025; Accepted: 28 Jul 2025.

Copyright: © 2025 Iurato, Dondero, Job, Stanzani, Leuzzi, Ingegnosi and Testa. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Matteo Iurato, University of Genoa, Genoa, Italy

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