In recent years, cognitive rehabilitation is shifting from paper-based to computer-based practice. Computerization entails several advantages, among which the availability of a great amount of stimuli to be used within a wide range of easily customizable exercise types and the possibility to monitor the evolution of a patient's skills through the storage of his performance data into a database. Furthermore, a computerized system can automatically assess the patient and adjust each exercise's difficulty accordingly. Patients undergoing exercises which fail to entertain them and stimulate their curiosity, are very likely to develop fatigue and boredom; besides, perceiving computerized rehabilitation as stressful and uncomfortable could very likely reduce the subject's compliance. For this reason great efforts are to be made in order to avoid the onset of stress states: this is why we chose to differentiate the exercises as much as possible before testing the tool on volunteers and patients. The results led us to improve the system, focusing mainly on the visual aspect of the exercises and to introduce 3D technology into our system.