Discourse studies in neurologically impaired populations: A quest for action

Organism and environment are in a state of constant interaction, and discou rse is viewed as one form of manifestation of this interaction. Through the study of discourse insights can be gained into those components that bring about mental events. Verbal structure, communication of beliefs and action /interaction are highly interactive dimensions of discourse. Taking this pe rspective as a framework, the findings of discourse studies with a particul ar emphasis on right-hemisphere brain-damaged individuals are discussed. Ne urolinguistic studies of discourse can be divided into four categories: (1) studies that focus primarily at providing a detailed description of the st ructural and interactional abilities of brain-damaged individuals, (2) stud ies that are mainly concerned with investigating the processing aspects of discourse, (3) studies that investigate the influence of cognitive systems such as attention or memory on discourse processing, and (4) studies that t ry to relate discourse processing mechanisms to underlying biological subst rates or neurophysiological mechanisms. A quest is made for future research to base discourse studies on well-defined processing theories, to include different processing components and levels, and to systematically investiga te the impact of facets of cognitive systems on such processing. Establishe d methodological approaches should be complemented by electrophysiological procedures (such as the event related potentials technique) or functional i maging techniques (such as fMRI) to tackle relationships between discourse processing mechanisms, cognitive systems and underlying biological mechanis ms. Consideration of the influence of biochemical processes (such as asymme tries of neurotransmitters, endocrine functions, or influence of pharmacolo gical agents) on component processes may add to our insights. (C) 1999 Acad emic Press.