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CC BY 4.0 · Methods Inf Med 2021; 60(S 02): e103-e110
DOI: 10.1055/s-0041-1740236
Original Article

Measurement Performance of Activity Measurements with Newer Generation of Apple Watch in Wheelchair Users with Spinal Cord Injury

Nils-Hendrik Benning
1   Institute of Medical Informatics, Heidelberg University Hospital, Heidelberg, Germany
,
Petra Knaup
1   Institute of Medical Informatics, Heidelberg University Hospital, Heidelberg, Germany
,
Rüdiger Rupp
2   Spinal Cord Injury Center, Heidelberg University Hospital, Heidelberg, Germany
› Institutsangaben
Funding This work was funded by the German Federal Ministry of Education and Research (BMBF) in the context of the ParaReg project (grant number 01GY1904) and the G-BA (Gemeinsamer Bundesausschuss) in the context of the NeuroMoves project (grant number 01VSF18032).
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Abstract

Background The level of physical activity (PA) of people with spinal cord injury (SCI) has an impact on long-term complications. Currently, PA is mostly assessed by interviews. Wearable activity trackers are promising tools to objectively measure PA under everyday conditions. The only off-the-shelf, wearable activity tracker with specific measures for wheelchair users is the Apple Watch.

Objectives This study analyzes the measurement performance of Apple Watch Series 4 for wheelchair users and compares it with an earlier generation of the device.

Methods Fifteen participants with subacute SCI during their first in-patient phase followed a test course using their wheelchair. The number of wheelchair pushes was counted manually by visual inspection and with the Apple Watch. Difference between the Apple Watch and the rater was analyzed with mean absolute percent error (MAPE) and a Bland–Altman plot. To compare the measurement error of Series 4 and an older generation of the device a t-test was calculated using data for Series 1 from a former study.

Results The average of differences was 12.33 pushes (n = 15), whereas participants pushed the wheelchair 138.4 times on average (range 86–271 pushes). The range of difference and the Bland–Altman plot indicate an overestimation by Apple Watch. MAPE is 9.20% and the t-test, testing for an effect of Series 4 on the percentage of error compared with Series 1, was significant with p < 0.05.

Conclusion Series 4 shows a significant improvement in measurement performance compared with Series 1. Series 4 can be considered as a promising data source to capture the number of wheelchair pushes on even grounds. Future research should analyze the long-term measurement performance during everyday conditions of Series 4.

Keywords

spinal cord injuries - exercise - fitness trackers - activity tracking

Notes

All patients gave permission according to the European General Data Protection Regulation for publication of their data in pseudonymized form. The data set supporting the conclusions of this article is available in the heiData repository of Heidelberg University: https://doi.org/10.11588/data/P1HEGO.




Publikationsverlauf

Eingereicht: 14. Juli 2021

Angenommen: 12. September 2021

Artikel online veröffentlicht:
02. Dezember 2021

© 2021. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/)

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