Hiram Brownell - US grants

We propose a program of research to test an explanation for the discourse impairments exhibited by stroke patients, especially those with right hemisphere brain damage. The main theme of this project is what has been termed a person's "theory of mind," i.e., his or her ability to infer and understand what beliefs, emotions, and motivations are in someone else's mind. The ability to attribute accurately mental states to other people plays a critical role in communication. For example, listeners need to infer speakers' beliefs and intentions in order to determine whether a nonveridical utterance (one that is not literally true) is an honest error, a deliberate lie, or an attempt at joking, teasing, or irony. That is, a speaker who states that the weather is great when it is raining may not know it is raining (an error), may know it's raining buy wants to deceive the listener (a lie), or may be joking about the weather (irony). Similarly, speakers need to infer what their listeners do and do not know in order to make their utterances informative and relevant: When asked what one is reading, it is not informative to reply "a book," since the speaker already knows this much. A relation between the ability to infer mental states and discourse ability has already been established in both normal and in autistic children. The proposed research has two major goals. First, we assess the abilities of both anterior and posterior groups of unilaterally right and left hemisphere damaged stroke patients to understand beliefs (which are nonobservable, mental, representational states) extends to other nonobservable states (e.g., hunger) and to nonmental representations (e.g., photographs), or reflects a selective deficit limited to understanding mental, representational states. Second, we test whether theory of mind deficits predict patients' performance in a range of discourse tasks. Some of these tasks require interpretation of nonveridical utterances as lies, mistakes, or irony, in which it is particularly critical to infer speakers' beliefs and intentions. Other tasks test subjects' abilities to adjust the form of literal utterances to reflect what a listener knows and does not know. The proposed research will be presented as a battery of tasks such that (with two exceptions explained in the text all subjects will participate in all tasks. the results of this project should provide a theoretical account of communication deficits that often characterize right hemisphere damaged patients and that can severely limit their long-term success in social and familial settings. This work may also shed more light on the surprisingly preserved discourse comprehension of left hemisphere damaged, aphasic patients.

[unreadable] DESCRIPTION (provided by applicant): This project addresses an important gap in the clinical literature: the dearth of tools for remediation of the communication deficits associated with brain damage caused by stroke in the right cerebral hemisphere and by traumatic brain injury. While not typically aphasic as measured by standard aphasia test batteries, many patients with these types of injury exhibit a range of communication impairments with non literal language that impact their lives in negative ways. The tasks comprising the training program are motivated by a theoretical analysis of the neuropsychology of metaphor comprehension deficits and related topics. One notion is that damage to right posterior regions limits a patient's ability to process connotative associations between words. A second notion is that damage to right frontal and bilateral prefrontal regions can affect working memory and a patient's ability to review information and to select a most relevant alternative from a set. The training is based on a simple mode of representing semantic relations in words and narratives, Thinking Maps, that has been used extensively with children. Thinking Maps explicitly list the semantic features or associations shared between words that provide potential bases for metaphors. Thinking Maps make available the ingredients of metaphor in concrete form for practice and review. The protocol, which is based on single subject experimental design, is designed to evaluate and remediate: 1) difficulty generating appropriate associations to words; 2) difficulty evaluating connotative shared meaning; and 3) difficulty selecting from among alternative interpretations. Each patient is expected to progress through the program spending more time on some tasks and less time on others as a function of that patient's specific profile of cognitive impairment. The protocol will examine what specifically changes during training and the impact of the intensity of training on the duration and generalizability of gains. In addition, the protocol will assess the fading of treatment gains over time and will explore approaches to slowing or preventing that decline! [unreadable] [unreadable] [unreadable]