Research on discursive cohesion and coherence has focused on patient groups with diffuse damage and widespread cognitive impairment (e.g.,TBI, dementia). Consequently, attempts to attribute discourse deficits to a particular cognitive domain has proven difficult. The current study capitalizes on a rare patient group with selective and severe anterograde hippocampal amnesia to investigate the contribution of declarative memory to discourse cohesion and coherence across a range of discourse genres. This research contributes to our understanding of the interdependent relationship between language and memory and promises to inform clinical decision making for individuals with complex cognitive-communication disorders following TBI and dementia

Duff, Melissa

Kurczek, Jake

The Aphasiology Archive

 Discourse Patterns  1  Coherence, cohesion, and declarative memory: Discourse patterns in patients with hippocampal amnesia Introduction  Everyday communication requires an ability to rapidly and accurately juggle cognitive, social, and linguistic capacities and to tie thoughts coherently into an organized narrative. With communication’s heavy demand on multiple cognitive systems (e.g., linguistic, emotion, memory, executive functions) (Hartly & Jensen, 1991), discourse analysis is a useful tool for investigating breakdowns in the complex orchestration of these systems in individuals with cognitive-communication disorders associated with traumatic brain injury (TBI) and Alzheimer’s disease (AD). Yet, while previous research has been helpful in identifying which discourse measures reliably differentiate patients with TBI or AD from their healthy counterparts, this work has been unable to form specific conclusions about which cognitive domains (e.g., memory, executive function) make critical contributions to a given behavior because of the diffuse nature of the pathology and the constellation of observed cognitive deficits (e.g.,Hartley & Jensen, 1992; Coelho, 2002; Youse & Coehlo, 2005). Taking advantaging of a rare patient group with selective and severe declarative memory impairments, the current study is an attempt to isolate the contribution of a given cognitive system (declarative memory) to successful discourse performance. In addition to informing our basic understanding of the cognitive systems that support language, this novel approach promises to inform clinical decision-making. Discursive Cohesion and Coherence One area of research that has been particularly fruitful in indentifying discourse level impairments in individuals with cognitive-communication impairments is investigations of discourse cohesion and coherence; our ability to seamlessly and flawlessly tie ideas together in connected speech and writing. Halliday and Hasan (1976) defined cohesion as surface indicators of relations within and between sentences. Cohesive elements or devices tie one part of a text to another and contribute to the discourse continuity (Ripich, Carpenter, & Ziol, 2000) (e.g., The husband and wife just moved to a new house, and she has been busy cleaning it.) and can take the form of references, conjunctions, and lexical markers (Dijkstra, Bourgeois, Allen, & Burgio, 2004; Liles & Coelho, 1998). Since the cohesive marker is a word that leads a listener to information outside of the sentence or utterance for meaning, a relationship is formed across sentences (Coelho, 1995). If a marker is ambiguous or misleading, cohesion and understanding is disrupted and communication is impeded (Van Leer & Turkstra, 1999). Coherence has been defined as the conceptual organization of discourse at the suprasentential level and depends on a speakers’ ability to maintain thematic unity. Coherence is further defined as either “global” or “local,” where global coherence is the overall organization in relation to the overall plan or theme and where local coherence is the conceptual link between individual sentences that maintain meaning in a text or discourse (Glosser & Deser, 1990; Agar & Hobbs, 1982). While patients with cognitive-communication impairments associated with TBI and dementia routinely  Discourse Patterns  2  have discourse level impairments in cohesion and coherence, the source of the underlying impairment has been difficult to determine and deficits have been attributed to impairments in  working memory (Dijkstra et al., 2004; Youse & Coelho, 2005), executive function (Coelho, 2002; Glosser & Deser, 1990), and broad cognitive dysfunction (Coelho, Liles, & Duffy, 1991, Davis & Coelho, 2004).  Cohesion, Coherence, and Declarative Memory  While the bulk of work directed at linking cohesion and coherence to memory has focused on a relationship with working memory, there are compelling reasons to investigate the contribution of declarative memory. First, the declarative memory system supports the creation of representations for successive events including information about the co-occurrences of people, places, and things, and the ability to link the spatial, temporal and interactional relations among them across time (Cohen & Banich, 2003). In discourse terms, successive events could be individual utterances or event structures within a narrative or a conversational topic that is repeated and returned to across time (e.g., picking up the thread of conversation a week later). Second, declarative memory impairment is a hallmark deficit in TBI and Alzheimer’s disease (Bourgeois & Hickey, 2009; Murray, Ramage, & Hopper, 2001; Richardson, 2000) and disruptions in discursive cohesion and coherence are prevalent in these populations (e.g., Youse & Coelho, 2005; Dijkstra et al., 2004).  Third, when correlating cohesive ties with a variety of memory measures in the discourse of individuals with TBI, Youse and Coelho (2005) reported a robust correlation with a measure of declarative memory (verbal paired associate learning) while all but one correlation with working memory measures were non-significant.   The current study is an initial attempt at understanding the specific and unique contribution of declarative memory to discursive cohesion and coherence by examining the discourse practices of individuals with selective and severe declarative memory impairments as a way to understanding the underlying impairment observed in patients with more widespread neuropsychological involvement. We hypothesize that patients with hippocampal amnesia will be impaired on measures of cohesion and coherence compared to healthy participants.   Methods Participants  This study analyzes previously collected data for cohesion and coherence across conversational, narrative and procedural discourse using a mediated discourse elicitation protocol (Hengst & Duff, 2007). Participants are six individuals (2 females) with hippocampal amnesia and six healthy comparison participants. Participants with amnesia were between 40 and 51 years old, had profound declarative memory deficits (mean WMS-III = 68.6 WAIS-III = 100.7) and hippocampal system damage following an anoxic event or herpes simplex encephalitis. In order to make better contact with the existing literature (e.g., Coelho et al., 1991; Coelho, 2002; Coelho et al., 2005: Liles et al., 1989; Youse & Coelho, 2005), we also collected new data on the same six participants with amnesia and six new healthy comparison participants having each participant complete a picture description task and a story retelling condition. All  Discourse Patterns  3  comparison participants are matched pair-wise to participants with amnesia on age, sex, handedness, and education.   Data Analysis Analysis is completed in four phases. First, all discourse samples are transcribed using a consensus procedure (see Duff et al., 2008). Second, all transcripts are divided into T-units (Hunt, 1970). Third, following Liles (1985), transcripts are coded for cohesive markers across three categories: reference, lexical and conjunctive. Decisions regarding adequacy of each cohesive tie are made. Fourth, following Glosser and Deser (1990) each transcript is rated for global and local coherence.  Results To date, training of coding procedures is complete, phases one and two are complete, and phases three and four have been initiated. Given our current level of progress we will have the full analysis completed by March 2010. Data from all phases and across all discourse genres will be presented with exemplars as well as a discussion of the results in the broader context of the literature on cohesion and coherence with special attention to the memory requisites of discursive cohesion and coherence.   Discussion Our prediction is that patients with hippocampal amnesia will be impaired on measures of cohesion and coherence compared to healthy participants. Regardless of whether or not this hypothesis holds, the analysis of discursive cohesion and coherence in a rare group of patients with selective and severe declarative memory impairments promises to contribute in interesting ways to our understanding of the relationship between memory and language, to elucidating the memory requisites of distinct discourse forms, and to refining our interventions for individuals with more complex cognitive-communication disorders due to TBI and AD. References Agar, M., & Hobbs, J. R. (1982) Interpreting discourse: Coherence and the analysis of ethnographic interviews. Discourse Processes, 5, 1-32.    Bourgeois, M.S., & Hickey, E. (2009). Dementia from diagnosis to management: A functional approach. New York: Taylor & Francis.  Coelho, C.A., Liles, B.Z., & Duffy, R.J. (1991). Discourse analyses with closed head injured adults: evidence for differing patterns of deficits. Arch Phys Med Rehabil,72(7), 465-8.  Coelho, C.A. (1995). Discourse production deficits following traumatic brain injury: A critical review of the recent literature. Aphasiology, 9(5), 409–429.  Discourse Patterns  4   Coelho, C.A. (2002). Story narrative of adults with closed head injury and non-brain-injured adults: influence of socioeconomic status, elicitation task, and executive functioning. Journal Speech Language Hearing Res, 45(6), 1232-48.  Coelho, C.A., Grela, B., Corso, M., Gamble, A., & Feinn, R. (2005). Microlinguistic deficits in the narrative discourse of adults with traumatic brain injury. Brain Injury, 19(13), 1139-45.  Cohen, N.J., & Banich, M.T. (2003). Memory. In M.T. Banich (Ed.), Neuropsychology: The neural bases of mental function (2nd ed., 322-364). Boston: Houghton-Mifflin.  Davis, G.A., & Coelho, C.A. (2004). Referential cohesion and logical coherence of narration after closed head injury. Brain and Language, 89(3), 508-23.  Dijkstra, K., Bourgeois, M.S., Allen, R.S., & Burgio, L.D. (2004). Conversational coherence: discourse analysis of older adults with and without dementia. Journal of Neurolinguistics, 17, 263-283.  Duff, M.C., Hengst, J., Tranel, D., & Cohen, N. (2008). Collaborative discourse facilitates efficient communication and new learning in amnesia. Brain and Language, 106, 41-54.  Glosser, G., & Deser, T. (1990). Patterns of discourse production among neurological patients with fluent language disorders. Brain and Language, 40, 67–88.  Halliday, M., & Hasan, R. (1976). Cohesion in English. London: Longman Group.  Hartley, L.L., & Jensen, P.J. (1991). Narrative and procedural discourse after closed head injury. Brain Injury, 5(3), 267-85.  Hartley, L.L., & Jensen, P.J. (1992). Three discourse profiles of closed-head-injury speakers: theoretical and clinical implications. Brain Injury, 6(3), 271-81.  Hengst, J.A., & Duff, M.C. (2007). Clinicians as communication partners. Topics in Language Disorders, 27(1), 37-49.  Hunt, K. (1970). Syntactic maturity in school children and adults. Monographs of the Society for Research in Child Development, 35 (Serial No. 134).  Liles, B. (1985). Narrative ability in normal and language-disordered children. Journal of Speech and Hearing Research, 23, 123–133.  Liles, B.Z., Coelho, C.A., & Zalagens, M.R. (1989). Effects of elicitation procedures on the narratives of normal and closed head-injured adults. Journal Speech Hearing Disorders, 54(3), 356-66.   Discourse Patterns  5  Liles, B.Z., & Coelho, C.A. (1998). Cohesion analysis. In L.R. Cherney, B.B. Shadden, & C.A. Coelho (Eds.), Analyzing discourse in communicatively impaired adults (pp. 65–84). Gaithersburg, MA: Aspen.  Murray, L. L., Ramage, A. E., & Hopper, T. (2001). Memory impairments in adults with neurogenic communication disorders. Seminars in Speech and Language, 22, 127-136.  Richardson, J.T.E. (2000). Clinical and Neuropsychological Aspects of Closed Head Injury. Philadelphia: Taylor and Francis.  Ripich, D.N., Carpenter, B.D., & Ziol, E.W. (2000). Conversational cohesion patterns in men and women with Alzheimer's disease: a longitudinal study. International Journal of Language & Communication Disorders, 35(1), 45-64.  Van Leer, E., & Turkstra, L. (1999). The effect of elicitation task on discourse coherence and cohesion in adolescents with brain injury. Journal Of Communication Disorders, 32, 327-349.  Youse, K.M., & Coelho, C.A. (2005). Working memory and discourse production abilities following closed-head injury. Brain Injury, 19(12), 1001-1009.  

Coherence, cohesion, and declarative memory: Discourse patterns in patients with hippocampal amnesia

Abstract

Similar works

Full text

Available Versions

The Aphasiology Archive