The purpose is to investigate whether animal-assisted therapy has positive biopsychosocial effects on patients with brain injuries. This study investigates the short-term biopsychosocial effects that occur when animals are present during therapy sessions in comparison to therapy sessions without animals, observing a group of 25 patients over 24 therapy sessions. While half of the sessions are held in presence of an animal and half without, they are as comparable as possible with respect to content and setting. In this study, patients who are in a slightly advanced rehabilitation process, assessed via their function profile, are investigated.