Domains of rehabilitation: a theoretical perspective.

On the basis of a taxonomy of functions an outline is given on potential deficits after brain lesions. The taxonomy distinguishes between "what"- and "how"-functions. Whereas for what-functions the localizing principle may apply, the how-functions being responsible for the logistics of the brain are non-locally represented. After brain injury the what- and how-functions may be differentially effected. On this basis 4 domains of functional rehabilitation can be distinguished, namely restitution and substitution of function after partly or complete losses of what-functions, activation and integration of function after alterations of activation or a disruption of functional coordination. Different strategies of functional rehabilitation are related to basic neurobiological principles which have been made responsible for restitution of function. Neuropsychological rehabilitation remains a challenge for neurobiology.