Technical validation of real-world monitoring of gait: a multicentric observational study
Authors: Mazzà Claudia , Alcock Lisa , Aminian Kamiar , Becker Clemens , Bertuletti Stefano , Bonci Tecla , Brown Philip , Brozgol Marina , Buckley Ellen , Carsin Anne-Elie , Caruso Marco , Caulfield Brian , Cereatti Andrea , Chiari Lorenzo , Chynkiamis Nikolaos , Ciravegna Fabio , Del Din Silvia , Eskofier Björn , Evers Jordi , Garcia Aymerich Judith , Gazit Eran , Hansen Clint , Hausdorff Jeffrey M , Helbostad Jorunn L , Hiden Hugo , Hume Emily , Paraschiv-Ionescu Anisoara , Ireson Neil , Keogh Alison , Kirk Cameron , Kluge Felix , Koch Sarah , Küderle Arne , Lanfranchi Vitaveska , Maetzler Walter , Micó-Amigo M Encarna , Mueller Arne , Neatrour Isabel , Niessen Martijn , Palmerini Luca , Pluimgraaff Lucas , Reggi Luca , Salis Francesca , Schwickert Lars , Scott Kirsty , Sharrack Basil , Sillen Henrik , Singleton David , Soltani Abolfazi , Taraldsen Kristin , Ullrich Martin , Van Gelder Linda , Vereijken Beatrix , Vogiatzis Ioannis , Warmerdam Elke , Yarnall Alison , Rochester Lynn 
Published: December 2021

IntroductionExisting mobility endpoints based on functional performance, physical assessments and patient self-reporting are often affected by lack of sensitivity, limiting their utility in clinical practice. Wearable devices including inertial measurement units (IMUs) can overcome these limitations by quantifying digital mobility outcomes (DMOs) both during supervised structured assessments and in real-world conditions. The validity of IMU-based methods in the real-world, however, is still limited in patient populations. Rigorous validation procedures should cover the device metrological verification, the validation of the algorithms for the DMOs computation specifically for the population of interest and in daily life situations, and the users’ perspective on the device.Methods and analysisThis protocol was designed to establish the technical validity and patient acceptability of the approach used to quantify digital mobility in the real world by Mobilise-D, a consortium funded by the European Union (EU) as part of the Innovative Medicine Initiative, aiming at fostering regulatory approval and clinical adoption of DMOs.After defining the procedures for the metrological verification of an IMU-based device, the experimental procedures for the validation of algorithms used to calculate the DMOs are presented. These include laboratory and real-world assessment in 120 participants from five groups: healthy older adults; chronic obstructive pulmonary disease, Parkinson’s disease, multiple sclerosis, proximal femoral fracture and congestive heart failure. DMOs extracted from the monitoring device will be compared with those from different reference systems, chosen according to the contexts of observation. Questionnaires and interviews will evaluate the users’ perspective on the deployed technology and relevance of the mobility assessment.Ethics and disseminationThe study has been granted ethics approval by the centre’s committees (London—Bloomsbury Research Ethics committee; Helsinki Committee, Tel Aviv Sourasky Medical Centre; Medical Faculties of The University of Tübingen and of the University of Kiel). Data and algorithms will be made publicly available.Trial registration numberISRCTN (12246987).