Personalization has become an important aspect in human-computer interaction. Not only differ users drastically regarding their interests, knowledge and individual prerequisites, they also have varying interaction capabilities. The latter is especially significant for users with different kinds of cognitive and/or motor impairments. Thus, the IAAA project investigates novel interaction methods as well as methods to model users' interaction capabilities in order to personalize the overall interaction process later. This paper focuses on physical pressure as an additional method to interact with common smart phones which could also be used to interact with other interactive systems. It compares four different ways of measuring physical pressure for the specific domain and presents the results of an initial user study that has been conducted with the target group in order to i) evaluate how well users can handle the respective interaction method and ii) how reliably the different approaches work.