[Verbal communication disorders and language disorders in cortical dementias (I). The current state of the art in research].
INTRODUCTION: This is the first part of a research work into primary and secondary language disorders (LD) in the stages of minimum to mild pathological deterioration in the degenerative process of cortical dementias. AIMS. In this first part, in the light of recent models of symbolic computation of language processing, we review the most significant publications on the subject matter. DEVELOPMENT: We begin with an introduction to the historical development of the approaches used to deal with the subject. Following that, we briefly describe the components of the language processing system (LPS) in the light of symbolic computation models. We then analyse the publications dealing with those models. Our aim was to determine whether the LD reported in those publications are the result of a primary involvement of any of the LPS components, or whether they are only the result of disorders affecting other components of the cognitive system. In this case, the supposed LD would be secondary and thus a communication, but not language, disorder. CONCLUSIONS: Despite the important variations from one individual to another that have been systematically observed by different authors, it seems that only LD belonging to so called primary progressive aphasia are actually cases of this disorder. In all the other dementias in the above mentioned stages of the development process these disorders are secondary to the involvement of other subsystems of the LPS.