We are Olga Morosow and Liesa Felser. We are senior year physical therapy students at Zuyd University of Applied Sciences in Heerlen (the Netherlands). We recently started with our bachelor thesis. For this thesis, we will investigate the validity of different activity monitors, such as the Fitbit One, Fitbit Flex, Jawbone Up24 and Activ8, in healthy persons and persons with a stroke or traumatic brain injury. Results of this study are expected in the summer of 2015.