Published on in Vol 6 , No 4 (2018) :Oct-Dec
Preprints (earlier versions) of this paper are
available at
https://preprints.jmir.org/preprint/9886, first published
.

1 Department of Geriatric Medicine, University Medical Center Groningen, University of Groningen, Groningen, NL
2 IJsfontein, Amsterdam, NL