Funding for this research was provided by:
Text and Data Mining valid from 2018-03-27
Received: 4 October 2017
Accepted: 22 February 2018
First Online: 27 March 2018
Ethics approval and consent to participate
: This study was approved by the Ethics committee of the University of Göttingen (04/2016). All experiments were conducted in accordance with the declaration of Helsinki, and all participants provided written informed consent prior to participation in the experiments.
: We obtained written informed consent for publication from all the study participants.
: DW works for the Otto Bock HealthCare GmbH, Germany. However, there are no competing interests concerned with the company.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.