Can inertial movement sensors (IMUs) provide a valid and reliable way of measuring Spinal Mobility in Axial Spondylo-arthritis (axSpa)? A clinimetric evaluation


The main objective of this project is to test the accuracy and reliability of electronic sensors in measuring spinal movement and to develop a new outcome tool for spinal mobility. Current methods rely on tape measures/goniometers and are not reliable/responsive enough to evaluate new treatments for axSpa. We have now completed three validation studies – a reliability study, a criterion validity study comparing sensor accuracy to the UCOTrack© gait lab system, and an exploratory ambulatory study.

A multi-centre study is underway testing the responsiveness of our IMU spinal mobility index alongside MRI pre/post biologics. We have also developed a smartphone app to allow researchers to use these electronic spinal mobility tools.

Facts and figures

Project lead
P Gardiner
Western Health and Social Care Trust
FOREUM resarch grant: €270.000

Meet the team

P Gardiner
Western Health and Social Care Trust
E Collantes Estevez
Fundacion para la Investigacion Biomedica de Córdoba
JL Garrido Castro
J Condell
University of Ulster
P Machado
University College London
F Wilson
Trinity College Dublin

External advisors/analysts

  • Dr J Connolly, Letterkenny Institute of Technology, IRELAND
  • Prof A Cuesta Vargas, Physiotherapy/ Sports Science, University of Malaga, SPAIN
  • Dr J Williams, Senior Lecturer, Physiotherapy/Engineering, University of Bournemouth, UK

Patient voice

Patient research partners in Spain and the UK have attended workshops to discuss the project. Patients are also involved in the design process for the smartphone application. The feedback from patients involved in home measurement testing has been very positive.

Interim results

The project started in April 2017. Results from the criterion validity & reliability studies patients were presented in 2019. These studies demonstrated both the accuracy and the reliability of IMU sensor based measurements of spinal mobility in axSpA (including rotation). We demonstrated that spinal mobility correlates with BASMI, BASFI and mSASSS. The ambulatory study has shown that unsupervised testing of spinal mobility is also a reliable alternative to supervised testing in the clinic. The completion of the responsiveness study will be delayed because of the covid19 crisis. A smartphone app has been developed to display the spinal mobility scores (see below).


Validity and Reliability of a Sensor Based Electronic Spinal Mobility Index for Axial Spondyloarthritis Rheumatology 2020 doi: 10.1093/rheumatology/keaa122

Abstracts EULAR 2019

  • THU0380: Lumbopelvic rhythm in patients with Axial Spondyloarthritis compared with low back pain and healthy subjects
  • SAT0659: Applying the OMERACT truth filter to a new electronic spinal mobility index for Axial Spondyloarthritis based on inertial measurement unit (IMU) sensors
  • SAT0327: Segmental relationship between mobility, structural damage and disease activity in Axial Spondyloarthritis