Consciousness and Aphasia

Abstract

Different language impairments allow us to investigate how much the use of language can influence the content of conscious awareness and therefore of thinking and reasoning. Pure anarthria (different from mutism) and verbal short-term memory deficits are associated with an impairment of the effect of covert speech on the content of working memory. Dynamic aphasia impairs the processes involved in the transition between thinking and speaking. However, even the most severe agrammatic patients can retain reasoning about others’ beliefs that according to some theories can only take place in explicit sentences of a natural language. Error monitoring is also impaired in many aphasic patients and in some of them is associated with complete lack of error awareness (anosognosia for aphasia). In patients with impaired consciousness whenever language examination is impossible or unreliable, fMRI and neurophysiological measures such as event-related potentials can provide a window for examining residual language capabilities.