Discourse studies in neurologically impaired populations: A quest for action

Abstract

Organism and environment are in a state of constant interaction, and discourse is vie-wed as one form of manifestation of this interaction. Through the study of discourse in-sights can be gained into those components that bring about mental events. Verbal structure, communication of beliefs and action/interaction are highly interactive dimensi-ons of discourse. Taking this perspective as a framework, the findings of discourse stu-dies with particular emphasis on right-hemisphere brain damaged individuals are discussed. Neurolinguistic studies of discourse can be divided into four categories: (1) studies that focus primarily at providing a detailed description of the structural and inter-actional abilities of brain-damaged individuals, (2) studies that are mainly concerned with investigating the processing aspects of discourse, (3) studies that investigate the influ-ence of cognitive systems such as attention or memory on discourse processing, and (4) studies that try to relate discourse processing mechanisms to underlying biological sub-strates 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 investigate the impact of facets of cogniti-ve systems on such processing. Established methodological approaches should be complemented by electrophysiological procedures (such as the event related potentials technique), or functional imaging techniques (such as fMRI) to tackle relationships bet-ween discourse processing mechanisms, cognitive systems and underlying biological mechanisms. Consideration of the influence of biochemical processes (such as asym-metries of neurotransmitters, endocrine functions or influence of pharmacological agents) on component processes may add to our insights.