Wearable inertial sensors for human movement analysis: a five-year update

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ABSTRACT

Introduction

The aim of the present review is to track the evolution of wearable IMUs from their use in supervised laboratory- and ambulatory-based settings to their application for long-term monitoring of human movement in unsupervised naturalistic settings.

Areas covered

Four main emerging areas of application were identified and synthesized, namely, mobile health solutions (specifically, for the assessment of frailty, risk of falls, chronic neurological diseases, and for the monitoring and promotion of active living), occupational ergonomics, rehabilitation and telerehabilitation, and cognitive assessment. Findings from recent scientific literature in each of these areas was synthesized from an applied and/or clinical perspective with the purpose of providing clinical researchers and practitioners with practical guidance on contemporary uses of inertial sensors in applied clinical settings.

Expert Opinion

IMU-based wearable devices have undergone a rapid transition from use in laboratory-based clinical practice to unsupervised, applied settings. Successful use of wearable inertial sensing for assessing mobility, motor performance and movement disorders in applied settings will rely also on machine learning algorithms for managing the vast amounts of data generated by these sensors for extracting information that is both clinically relevant and interpretable by practitioners.

KEYWORDS:

• Accelerometry
• gait analysis
• kinematics
• biomechanics
• motor assessment
• motion analysis
• ergonomics
• telerehabilitation
• rehabilitation
• mHealth
• activity monitoring
• remote monitoring

Article Highlights

• Interest in wearable inertial sensors has increased exponentially in recent years. They are widely accepted for clinical assessment of motor disorders in both, supervised and unconstrained settings.

• In the last five years, wearable IMUs have become an emerging solution for remote health monitoring with the advantage of higher sensitivity and specificity than traditional clinical assessment methods.

• Frailty, falls, movement disorders and promotion of active living are among the most emergent and clinically significant applications of wearable IMUs for mHealth. While research is still nascent, smartphones potentially offer a ubiquitous platform solution for all these mHealth applications.

• The SARS-COV-2 pandemic has increased societal awareness about the importance of virtual healthcare and digital health through remote and personalized care delivery solutions. To this end, wearable IMUs play a crucial role given their ability to yield patient-specific data for early detection of movement disorders, and the remote supervision and assessment of the long-term efficacy of interventions.

• Design and validation of wearable IMUs intended for mHealth solutions should be managed according to international standards of medical certification and privacy policy.

• Use cases of wearable IMUs also extend to occupational settings for ergonomics assessment to ascertain workers’ risk of developing musculoskeletal disorders. Specifically, IMUs are being used to measure and characterize the intensity of extreme motions and postures, mechanical loads at the main joints of the worker’s body, to detect physical fatigue, and to provide real-time feedback about unsafe work conditions.

• Sensor-based rehabilitation for neurological and orthopedics patients is increasingly pervasive and helps improve the efficacy of rehabilitation therapy interventions in both, in-person and remote settings.

• Wearable sensors combined with serious-gaming, augmented and/or virtual reality will continue to be an important component of telerehabilitation and homecare-based technology solutions.

• The vast amounts of continuous data streams generated by wearable sensors will place AI/ML and neural networks at the next frontier of disruption in clinical decision-making.

Declaration of Interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Additional information

Funding

This article was not funded.