 - Open questions concerning demographic data and prosthesis-related questions 15: These questions are used to determine further factors that may influence the outcome of self-rated and performance-based tests. They include factors that are already known to influence upper extremity function or perceived disability e.g rate at amputation, time since amputation, dominant vs. non-dominant hand, as well as factors that may influence the outcome, but were not studied before in sufficient detail as living alone. 