Facilitating Trunk EnduranceAssessment by means of Mobile

Health TechnologiesOresti Banos, Jaehun Bang, Donguk Kang,

Choong Seon Hong, Sungyoung Lee

Ubiquitous Computing Lab, Department of Computer Engineering, Kyung Hee University, Korea

oresti@oslab.khu.ac.kr

Trunk endurance tests are widely used in physical medicine to assess the muscle status of people affected by low back pain. Nevertheless,traditional evaluation procedures suffer from practical limitations, which can lead to potential misdiagnoses. This work presents mDurance,a novel mobile health system aimed at supporting specialists in the functional assessment of trunk endurance by using wearable and mobiledevices. The system makes use of a wearable inertial sensor to track the patient trunk posture, while portable electromyography sensors areemployed to seamlessly measure the electrical activity produced by the trunk muscles. The information registered by the sensors isprocessed and managed by a mobile application that facilitates the expert normal routine, while reducing the impact of human errors andexpediting the analysis of the test results. The reliability and usability of mDurance is proved through a case study, thus demonstrating itspotential interest for regular physical therapy routines.

Keywords: Mobile Health; Physical Therapy; Trunk Endurance; Inertial Sensors; EMG Sensors

Abstract

Trunk Endurance Assessment - TEA

The system consists of a wearable inertial sensor to estimate the trunk positionand an attachable electromyography sensor to measure the activity of theskeletal muscles of the trunk. The sensor data is transmitted to a mobileapplication for the data processing and analysis. The app automatically estimatesthe duration of the test, presents the physiological responses of the patient andgenerates reports summarizing the patient status and evolution.

mDurance: a Novel Mobile Health System for TEA

This work was supported by the Industrial Core Technology Development Program (10049079,Development of mining core technology exploiting personal big data) funded by the Korean Ministryof Trade, Industry and Energy. This work was also supported by the Junta de Andalucia Project P12-TIC-2082 and FPU Spanish Grant AP2012-1789.

Jose Antonio Moral Munoz, Ignacio Diaz Reyes, Manuel Arroyo Morales, Miguel Damas, Hector

Pomares, Ignacio Rojas, Claudia Villalonga

Research Centre for Information and Communications Technology, University of Granada, Spain

mDuranceApp

mDuranceSensors

mDuranceCore

Technology

ACC, GYR, MAG, EMG

Ten volunteers (8 males and 2 females, 21-37 years old) were recruited to beevaluated by three external physical therapists using both mDurance andtraditional procedures:

• In the traditional approach experts had to visually determine the start and end ofeach test and time it using a stopwatch ΔTtraditional

• When using mDurance these processes were automated ΔTmDurance

Evaluation

Inter-rater reliability• Measures the agreement between

both methods (ΔTtraditional –ΔTmDurance)

• All the differences fall within thelimits of agreement, thusconfirming that both methods canbe used interchangeably

Usability• Experts appreciate the practicality of

the automatic angle measurementto determine the user start positionand to estimate the end-of-test

• They also value the EMG onlinerepresentation to observe themuscle contraction during the test

• System Usability Scale (SUS) scoresindicated high levels of acceptability,ease of use and confidence whenutilizing mDurance

Acknowledgements

TEA consists in the measurement of the time a person can hold aspecific posture involving the trunk muscles:• The Sorensen test is the most common medical procedure for TEA• The subject has to hold a horizontal unsupported posture while extending the

upper body beyond the edge of a bench• The timing begins when the posture is horizontal and unsupported, and the

test ends when a) the position is held 240s or b) the trunk position drops >10°

HighSubjectivity

Limitations of traditional TEA:• The human expert has to estimate the start and end visually• The expert has to supervise various aspects simultaneously,

such as time, position, and possible abnormalities during thetest

• Specialists elaborate their diagnosis on the recorded time, andthat is the only information to compare with in future tests