Melissa Duff - US grants

[unreadable] DESCRIPTION (provided by applicant): The goal of this project is to contribute to the understanding of the neural basis for and relationship between memory and language, by investigating the acquisition and use of "common ground" in communication. The experimental approach uses the lesion method to interrelate neuropsychological and neuroanatomical findings, using both group studies and multiple single-case studies of neurological patients with focal brain lesions. The proposed work builds on an exciting finding from my doctoral work: severely amnesic patients can acquire common ground (shared referential labels used to facilitate rapid and efficient communication) in regular interactions with familiar partners. The crucial cognitive components and neuroanatomical correlates of this learning, however, have yet to be determined. One principle aim here is to define and characterize those cognitive and neural mechanisms supporting common ground in communication. The nature of the task used in my experimental work involves "real-world" learning and communication. The fact that individuals with amnesia performed so well in this truly real-world type of collaborative interaction is very exciting with respect to rehabilitation possibilities. The second aim of this work is to test the clinical efficacy of this paradigm by designing and implementing a collection of single case intervention studies using the collaborative referencing task in patients with circumscribed impairments of learning and memory, aimed at improving their daily functioning. [unreadable] [unreadable] [unreadable]

DESCRIPTION (provided by applicant): This research program explores the novel hypothesis that many of the processes by which we produce and understand language also place high demands on and receive contributions from the hippocampal declarative memory system. This system is uniquely positioned to access and integrate discourse, contextual and experiential information that the language processing system relies on to resolve ambiguity and create meaning. Recent provocative work extends the traditional view of declarative memory as contributing exclusively to long-term memory, to include a critical role in the generation and use of on-line representations, created during ongoing and online information processing to support behavioral performance in the moment. The proposed studies build upon a set of exciting preliminary findings revealing language deficits at low levels of language processing (i.e., within a single noun phrase), and in the absence of any explicit demands on memory (e.g., no delays; when all the stimuli remain in view) in patients with severe and selective declarative memory impairment. Our studies are built around investigating three key areas of language processing where proposals of the memory determinants are central, but untested: Aim 1: To investigate the demands of interactive dialogue on declarative memory; Aim 2: To investigate the demands of referential processing on declarative memory; Aim 3: To investigate the demands of accommodation of talker variability on declarative memory. Our experimental approach capitalizes on a compelling opportunity to combine the study of patients with hippocampal amnesia with eye tracking and behavioral measures to examine the necessity of a form of memory in meeting the demands of language. We will therefore be uniquely able to determine the contributions of hippocampus and declarative memory to language processing and use across multiple levels of language production and comprehension providing crucial tests of hypothesized roles for memory in language use. Language disruptions are common in many neurological and psychiatric conditions where impairments in declarative memory are also prominent, including stroke, traumatic brain injury, Alzheimer's disease, and schizophrenia. Thus, our efforts to characterize the observed language deficits and link them to underlying memory mechanisms are necessary for understanding the broader neural network and cognitive processes that support language use and for developing more sensitive assessments and effective interventions. This application, and the findings generated, offers unparalleled insights and advancements for theories of language processing, clinical service delivery to individuals with concomitant disorders of language and memory, and understanding the organization and operation of language in the brain.

Abstract Social media and other computer-mediated communication (CMC) platforms have radically changed the way we work, live, and build and maintain our social lives. Today, there are more than three billion social media users worldwide, representing 42% of the world?s population. For individuals with disabilities, CMC has the potential to overcome existing barriers to social participation, particularly for individuals with motor or sensory limitations. However, current CMC social-media platforms are not designed with individuals with cognitive limitations in mind; thus, they do not address barriers to social participation for individuals with cognitive disabilities, including individuals with traumatic brain injury (TBI) who have impairments in memory, social perception, and social communication. Adults with moderate-severe TBI report being socially isolated, and while they do use social media for social interactions and to share experiences, they do so less frequently than their uninjured peers and report significant challenges with accessibility and usability. CMC has been linked to increased feelings of well-being and social connectedness and decreased loneliness, which in turn are linked with positive physical and psychological health. Reducing barriers to CMC platforms for survivors of TBI may improve social communication, participation, and overall health outcomes. The overarching aim of this project is to create evidence- and technology-based aids for CMC, specifically for social media use, and evaluate users? perceptions of these aids. These data will be used to develop a subsequent clinical trial proposal that will test the effects of CMC technology aids on social participation in adults with TBI. In preparation for the clinical trial to test the effects of technology-aid use on social participation and health outcomes, we must first develop and test the technology, which we do here across three proposed aims: Aim 1: Develop software technology to support social media use by adults with TBI; Aim 2. Determine user perceptions and usage patterns of technology aids and patient characteristics to test in a future clinical trial; Aim 3. Develop a clinical- trial proposal. Through the development, testing, and deployment of technology aids to support social-media use and the development of a clinical-trial proposal, this project lays the critical foundation for reducing barriers to social participation for individuals with TBI and improving social functioning and wellbeing. Our research team possesses the rare combination of expertise in human machine interactions, technology development, social communication impairment in TBI, patient-centered outcomes, and the relation between CMC and well- being required to conduct the proposed work

ABSTRACT Adults with traumatic brain injury (TBI) have chronic deficits in cognitive-communication and these impairments have been linked to negative outcomes and poor community reintegration and independence. A significant challenge in the field is that commonly used methods to detect these deficits in clinical and research settings lack the required sensitivity and have focused on a limited subset of discourse tasks that do not reliably predict communication outcomes. At the heart of our proposal is the idea that current theories of cognitive- communication are too narrow and the methods used to detect deficits are too limiting. In contrast to current conceptualizations which state that cognitive-communication deficits affect discourse and conversation (leaving basic sentence level processing intact), we propose that cognitive-communication impairment is a deficit in the flexible use and processing of language that manifests across the varied and dynamic contexts of everyday language use, whether processing a single sentence or participating in a multiparty conversation. For example, individuals with TBI make inappropriate or irrelevant comments, suggesting a failure to consider the communicative setting and the perspective of their conversational partners, as well as insensitivity to contextual cues (environmental, partner) that guide language use. These are problems using and processing language in context. From this perspective, there is a striking disconnect in the field between clinical observations of impairments in using language in context and the widespread use of decontextualized tasks and measures to capture these deficits in the lab and clinic (e.g., monologue discourse task). Using ecologically valid language tasks and methods sensitive enough to detect even subtle, though meaningful, disruptions in language, the proposed work endeavors to show that deficits in contextual language processing in TBI extend even to the rapid processing of individual phrases and sentences in the moment (i.e., online processing), can be captured in controlled settings, and that such deficits predict communicative outcome. The proposed program of research represents a novel direction in the study of TBI with substantial basic science and clinical translational significance. The proposal is organized around three AIMS: (1) To investigate language processing in context in TBI; (2) To investigate language use in group settings in TBI; (3) To determine the relationship between language processing in context and communicative outcome. This proposal is unique in the field and uniquely promising for understanding the nature of deficits in contextual language processing following TBI and, ultimately, improving rehabilitation intervention outcomes.

Abstract Adults with traumatic brain injury (TBI) have deficits in flexible and goal-directed behavior and these impairments have been linked to negative outcomes and poor community reintegration and independence. The frontal lobes, and their putative functions of executive control and working memory, have figured prominently, and nearly exclusively, in mechanistic accounts of flexible and adaptive behavior and in understanding the underlying nature of behavioral dysfunction in individuals with TBI. Yet, interventions designed to target the frontal lobes have not yielded significant improvements in behavior or independence in the community. We propose that the frontal lobes may be the wrong, or not the only, mechanism of impairment leading to inflexible and maladaptive behavior in TBI. We aim to show that flexible and goal-directed behavior depends critically on the operation of the hippocampal relational memory system and is a key mechanism in the observed behavioral dysfunction and poor outcomes in individuals with TBI. The proposed program of research represents a novel direction in the study of traumatic brain injury with substantial basic science and clinical translational significance. The proposal is organized around four AIMS: (1) To characterize disruptions in the integrity of the structure of the hippocampal system and their impact on relational memory in individuals with traumatic brain injury. (2) To characterize the impact of relational memory impairments on flexible and goal- directed behavior in individuals with traumatic brain injury. (3) To investigate the impact of disruption of the hippocampal system and relational memory on the larger network of structures participating in flexible and goal-directed behavior in individuals with traumatic brain injury. (4) To determine the relationship between impairment in relational memory and community integration and independence in individuals with traumatic brain injury. This proposal is unique in the field and uniquely promising for understanding the nature of behavioral dysfunction in TBI and, ultimately, improving rehabilitation intervention outcomes. Indeed, the proposed work lays the critical foundation for the identification of objective and diagnostic biomarkers for behavioral dysfunction following TBI and for the development of new rehabilitative targets. Linking behavioral dysfunction in TBI to the hippocampal relational memory system will also inform the characterization of a number of other neurological (e.g., stroke, TBI, Alzheimer's disease), psychiatric (e.g., schizophrenia, depression), and developmental (e.g., autism) conditions that affect hippocampal relational memory and where deficits in flexible and goal-directed behavior are also hallmark.

ABSTRACT A significant challenge in the empirical study and clinical management of cognitive-communication impairment, a hallmark deficit in individuals with traumatic brain injury (TBI) and Alzheimer's disease (AD), is that commonly used methods to detect these deficits in clinical and research settings lack the required sensitivity and have focused on a limited subset of discourse tasks that do not reliably predict communication outcomes. At the heart of our proposal is the idea that current theories of cognitive-communication are too narrow and the methods used to detect deficits are too limiting. In contrast to current conceptualizations which state that cognitive-communication deficits affect discourse and conversation (leaving basic sentence level processing intact), we propose that cognitive-communication impairment is a deficit in the flexible use and processing of language that manifests across the varied and dynamic contexts of everyday language use, whether processing a single sentence or participating in a multiparty conversation. From this perspective, there is a striking disconnect in the field between clinical observations of impairments in using language in context and the widespread use of decontextualized tasks and measures to capture these deficits in the lab and clinic (e.g., monologue discourse task). Using ecologically valid language tasks and methods sensitive enough to detect even subtle, though meaningful, disruptions in language, this administrative supplement extends our work on language processing in TBI to individuals with Alzheimer's disease. The proposed program of research represents a novel direction in the study of cognitive communication impairment in individuals with AD with substantial basic science and clinical translational significance. The proposal is organized around two AIMS: (1) To investigate language processing in context in AD; (2) To investigate language use in group settings in AD. This proposal is unique in the field and uniquely promising for understanding the nature of deficits in contextual language processing and, ultimately, improving rehabilitation intervention outcomes.