Conscious patients with severe motor and speech disorders have great difficulty interacting with the environment and communicating with other people. Several augmentative communication devices are now available to exploit these patients' expressive potential, but their use often demands considerable cognitive effort. Non-communicative patients with severe brain lesions may have, in addition, specific cognitive deficits that hinder the efficient use of augmentative communication methods. Some neuropsychological batteries are now available for testing these patients. On the basis of such cognitive assessments, cognitive rehabilitation training can now be applied, but we underline that this training must be tailored to single patients in order to allow them to communicate autonomously and efficiently.