Spontaneous speech in senile dementia and aphasia: implications for a neurolinguistic model of language production

A tutorial on discourse analysis in healthy and pathological ageing

BACKGROUND

Age is a key factor when dealing with language and speech disorders, as it entails a progressive loss of neuroplasticity even in healthy individuals. Apart from this, ageing also affects our word-retrieval abilities, and thus, our discursive skills, particularly in people suffering from neurodegenerative diseases. Therefore, descriptions and/or measures of communicative performance always need to be interpreted through the lens of variation across the lifespan.

AIM

This paper's main objective is to create a general tutorial for researchers willing to start delving into discourse analysis, both in healthy and pathological ageing.

METHODS

An eight-step tutorial on discourse analysis in the elderly is presented. Each of these steps starts with general recommendations and progresses to more specific topics that may be relevant when conducting this type of research. All of the steps have been extrapolated from an extensive literature review on discourse analysis.

MAIN CONTRIBUTIONS

This work presents an easy-to-follow, step-by-step tutorial on discourse analysis in the elderly. It is aimed at clinical researchers who are taking their first steps in discourse analysis.It may also be useful for those who are already familiar with the methodology but may be interested in reading a general overview on the topic. Moreover, it offers new insights into the following topics: types of research questions, advantages and disadvantages of the different research methodologies and ethical considerations for data production in clinical linguistics.

CONCLUSIONS

Discourse analysis in the elderly is a highly complex issue that may require researching from different approaches and disciplines. This implies following a well-planned and thorough process, which we have detailed through the following eight steps: (i) reviewing literature; (ii) formulating the research question; (iii) designing the study; (iv) producing data; (v) selecting technological tools for data treatment; (vi) transcribing the corpus; (vii) annotating the corpus and (viii) analysing and interpreting the results.

WHAT THIS PAPER ADDS

What is already known on the subject Approaches in discourse analysis in elderly adults, and particularly, in people suffering from dementia have already been analysed by previous researchers and categorised into three main trends: the quantitative-experimental approach, the qualitative-naturalistic approach and an in-between path, the quantitative-naturalistic approach. Also, several handbooks on general discourse analysis have presented comprehensive revisions on potential resources and methodologies that can be applied to researching discourse in elderly populations. What this paper adds to existing knowledge This paper takes these three main approaches and analyses how the most recent research on language in ageing and dementia fits into them. Furthermore, it reviews the advantages and disadvantages each of them may bring for beginners in the field of discourse analysis. Moreover, it adds some studies that may fit into a fourth approach: the qualitative-experimental. This article also presents information about several of the main steps when analysing data from the pragmatic perspective: the formulation of the research question, data production and the transcription/annotation process. What are the potential or actual clinical implications of this work? This work has been devised for linguists who may want to read a systematization of the steps for analysing discourse in elderly populations. It may also be of interest to specialists from different fields such as speech therapy, psychology, gerontology or neurology who desire to start applying methods from discourse analysis in their work and aim to have a comprehensive scope of the main research trends within the field of clinical pragmatics.

Methodologies for assessing morphosyntactic ability in people with Alzheimer's disease

BACKGROUND

The detection and description of language impairments in neurodegenerative diseases like Alzheimer's Disease (AD) play an important role in research, clinical diagnosis and intervention. Various methodological protocols have been implemented for the assessment of morphosyntactic abilities in AD; narrative discourse elicitation tasks and structured experimental tasks for production, offline and online structured experimental tasks for comprehension. Very few studies implement and compare different methodological protocols; thus, little is known about the advantages and disadvantages of each methodology.

AIMS

To discuss and compare the main behavioral methodological approaches and tasks that have been used in psycholinguistic research to assess different aspects of morphosyntactic production and comprehension in individuals with AD at the word and sentence levels.

METHODS

A narrative review was conducted through searches in the scientific databases Google Scholar, Scopus, Science Direct, MITCogNet, PubMed. Only studies written in English, that reported quantitative data and were published in peer-reviewed journals were considered with respect to their methodological protocol. Moreover, we considered studies that reported research on all stages of the disease and we included only studies that also reported results of a healthy control group. Studies that implemented standardized assessment tools were not considered in this review.

OUTCOMES & RESULTS

The main narrative discourse elicitation tasks implemented for the assessment of morphosyntactic production include interviews, picture-description and story narration, whereas the main structured experimental tasks include sentence completion, constrained sentence production, sentence repetition and naming. Morphosyntactic comprehension in AD has been assessed with the use of structured experimental tasks, both offline (sentence-picture matching, grammaticality judgment) and online (cross-modal naming,speeded sentence acceptability judgment, auditory moving window, word detection, reading). For each task we considered studies that reported results from different morphosyntactic structures and phenomena in as many different languages as possible.

CONCLUSIONS & IMPLICATIONS

Our review revealed strengths and weaknesses of these methods but also directions for future research. Narrative discourse elicitation tasks as well as structured experimental tasks have been used in a variety of languages, and have uncovered preserved morphosyntactic production but also deficits in people with AD. A combination of narrative discourse elicitation and structured production tasks for the assessment of the same morphosyntactic structure has been rarely used. Regarding comprehension, offline tasks have been implemented in various languages, whereas online tasks have been mainly used in English. Offline and online experimental paradigms have often produced contradictory results even within the same study. The discrepancy between the two paradigms has been attributed to the different working memory demands they impose to the comprehender or to the different parsing processes they tap. Strengths and shortcomings of each methodology are summarized in the paper, and comparisons between different tasks are attempted when this is possible. Thus, the paper may serve as a methodological guide for the study of morphosyntax in AD and possibly in other neurodegenerative diseases.

WHAT THIS PAPER ADDS

What is already known on this subject For the assessment of morphosyntactic abilities in AD, various methodological paradigms have been implemented: narrative discourse elicitation tasks and structured experimental tasks for production, and offline and online structured experimental tasks for comprehension. Very few studies implement and compare different methodological protocols; thus, little is known about the advantages and disadvantages of each methodology. What this paper adds to existing knowledge The paper presents an overview of methodologies that have been used to assess morphosyntactic production and comprehension of people with AD at the word and sentence levels. The paper summarizes the strengths and shortcomings of each methodology, providing both the researcher and the clinician with some directions in their endeavour of investigating language in AD. Also, the paper highlights the need for further research that will implement carefully scrutinized tasks from various experimental paradigms and will explore distinct aspects of the AD patients' morphosyntactic abilities in typologically different languages. What are the potential or actual clinical implications of this work? The paper may serve as a reference point for (psycho-)linguists who wish to study morphosyntactic abilities in AD, and for speech and language therapists who might need to apply morphosyntactic protocols to their patients in order to assess them or design appropriate therapeutic interventions for production and comprehension deficits.

Lexical-semantic properties of verbs and nouns used in conversation by people with Alzheimer's disease

Alzheimer's disease (AD) is accompanied by language impairments and communicative breakdowns. Research into language processing by people with AD (pwAD) has focused largely on production of nouns in isolation. However, impairments are consistently found in verb production at word and sentence levels, and comparatively little is known about word use by pwAD in conversation. This study investigated differences between pwAD and cognitively healthy controls in conversational use of nouns, verbs, and pronouns. Speech samples produced by 12 pwAD and 12 controls for the Carolinas Conversations Collection were analysed for noun, verb and pronoun counts and ratios, lexical diversity overall and among nouns and verbs, copula use, and frequencies and ages of acquisition (AoA) of nouns and verbs produced. pwAD used fewer nouns and a narrower range of words than controls, exhibiting signs of increased reliance on pronouns and decreased noun diversity. Age affected noun frequencies differently within each group-pwAD produced nouns of lower frequencies with age, while controls produced nouns of higher frequencies. pwAD produced nouns of higher AoA than controls. Verb use differed little by group. These findings highlight the need to account for differences between nouns and verbs, including in frequency, AoA, proportion of all words spoken, and context-dependent processing demands, when drawing conclusions on language use by pwAD. They also suggest potential for communicative interventions targeting contextual use of both nouns and verbs.

The Subjective Experience of Word-Finding Difficulties in People With Aphasia: A Thematic Analysis of Interview Data

PURPOSE

Anomia, or difficulty with naming and word finding, is a pervasive deficit among individuals with aphasia. There is an extensive literature on the mechanisms underlying anomia and on approaches to treatment, but very little is known about the subjective experience of anomia during day-to-day life.

METHOD

As part of a larger testing battery, 53 adults with poststroke aphasia took part in a novel, structured interview that included an open-ended question about the general experience of anomia: "Do you ever know what you want to say, but you can't say it out loud? Please describe that feeling." Video-recorded interview responses were transcribed and analyzed using thematic analysis, an iterative, data-driven process that categorizes interview data into common themes.

RESULTS

Five main themes emerged among the data from 37 participants who produced adequate responses for use in thematic analysis: strategies to cope with or compensate for anomia, comments on awareness of the level of breakdown (e.g., "I have an idea, but can't get the right words"), negative emotions, impact on relationships, and changes in frequency over time.

CONCLUSIONS

Participants showed strong awareness of anomia and its implications, demonstrating an ability to describe their language breakdown, identify relevant strategies to compensate and/or cope, and acknowledge the impact of anomia on their emotions and social interactions. This patient perspective may serve as a valuable supplement to information typically gained via objective language assessments. Clinicians and researchers may wish to consider incorporating similar subjective measures during assessment and treatment planning. Supplemental Material https://doi.org/10.23641/asha.15032643.

Changes in Pronoun Use a Decade before Clinical Diagnosis of Alzheimer’s Dementia. Linguistic Contexts Suggest Problems in Perspective-Taking

The use of pronouns has been shown to change pathologically in the early phases of Alzheimer’s Dementia (AD). So far, the findings have been of a quantitative nature. Little is known, however, about the developmental path of the change, its onset, the domains in which it initially occurs, and if and how it spreads to other linguistic domains. The present study investigates pronoun use in six speakers of German a decade before they were clinically diagnosed with AD (LAD) and six biographically matched healthy controls (CTR). The data originate from monologic spoken language elicited by semi-spontaneous biographical interviews. Investigation of nine pronoun types revealed group differences in the use of three pronoun types: D-pronouns—a specific pronoun type of German for reference to persons and objects; the impersonal pronoun man ‘one’, and the propositional pronoun das ‘this/that’. Investigation of the linguistic contexts in which these three pronoun types were used revealed a correlation with declines in elaborative and evaluative information; that is, information the hearer would benefit from in creating an informed model of the discourse. We, therefore, hypothesize that the early changes in language use due to AD point to problems in perspective-taking, specifically in taking the hearer’s perspective.

Language changes in Alzheimer's disease: A systematic review of verb processing

Alzheimer's disease (AD) results in language impairments and higher-level communication problems. Research into the language of people with AD (pwAD) has mainly focused on nouns; however, improved understanding of verb processing by pwAD could improve diagnostic assessments and communicative interventions. This systematic review synthesizes findings of AD's effects on verbs from single-word, sentence, and discourse tasks. Review of 57 studies revealed that pwAD were less accurate than controls on single-word tasks and less accurate with verbs than nouns on these tasks. They had difficulty comprehending sentences featuring multiple verbs or verbs with reversible thematic roles. Discourse production by pwAD was marked by vagueness, including declines in total output and propositional content and a preference for generic verbs and simple syntax. Few studies examining sentence production or discourse comprehension were found. Future research should address relationships between long-term memory and language preservation as well as verb use in discourse.

Connected Speech Characteristics of Bengali Speakers With Alzheimer's Disease: Evidence for Language-Specific Diagnostic Markers

Background and aim: Speech and language characteristics of connected speech provide a valuable tool for identifying, diagnosing and monitoring progression in Alzheimer's Disease (AD). Our knowledge of linguistic features of connected speech in AD is primarily derived from English speakers; very little is known regarding patterns of linguistic deficits in speakers of other languages, such as Bengali. Bengali is a highly inflected pro-drop language from the Indo-Aryan language family. It is the seventh most spoken language in the world, yet to date, no studies have investigated the profile of linguistic impairments in Bengali speakers with AD. The aim of this study was to characterize connected speech production and identify the linguistic features affected in Bengali speakers with AD. Methods: Participants were six Bengali speaking AD patients and eight matched controls from the urban metropolis, Kolkata, India. Narrative samples were elicited in Bengali using the Frog Story. Samples were analyzed using the Quantitative Production Analysis and the Correct Information Unit analyses to quantify six different aspects of speech production: speech rate, structural and syntactic measures, lexical measures, morphological and inflectional measures, semantic measures and measure of spontaneity and fluency disruptions. Results and conclusions: In line with the extant literature from English speakers, the Bengali AD participants demonstrated decreased speech rate, simplicity of sentence forms and structures, and reduced semantic content. Critically, differences with English speakers' literature emerged in the domains of Bengali specific linguistic features, such as the pro-drop nature of Bengali and its inflectional properties of nominal and verbal systems. Bengali AD participants produced fewer pronouns, which is in direct contrast with the overuse of pronouns by English AD participants. No obvious difficulty in producing nominal and verbal inflections was evident. However, differences in the type of noun inflections were evident; these were characterized by simpler inflectional features used by AD speakers. This study represents the first of its kind to characterize connected speech production in Bengali AD participants and is a significant step forward toward the development of language-specific clinical markers in AD. It also provides a framework for cross-linguistic comparisons across structurally distinct and under-explored languages.

Transformer-based deep neural network language models for Alzheimer's disease risk assessment from targeted speech

BACKGROUND

We developed transformer-based deep learning models based on natural language processing for early risk assessment of Alzheimer's disease from the picture description test.

METHODS

The lack of large datasets poses the most important limitation for using complex models that do not require feature engineering. Transformer-based pre-trained deep language models have recently made a large leap in NLP research and application. These models are pre-trained on available large datasets to understand natural language texts appropriately, and are shown to subsequently perform well on classification tasks with small training sets. The overall classification model is a simple classifier on top of the pre-trained deep language model.

RESULTS

The models are evaluated on picture description test transcripts of the Pitt corpus, which contains data of 170 AD patients with 257 interviews and 99 healthy controls with 243 interviews. The large bidirectional encoder representations from transformers (BERT_Large) embedding with logistic regression classifier achieves classification accuracy of 88.08%, which improves the state-of-the-art by 2.48%.

CONCLUSIONS

Using pre-trained language models can improve AD prediction. This not only solves the problem of lack of sufficiently large datasets, but also reduces the need for expert-defined features.

Language impairment in adults with end-stage liver disease: application of natural language processing towards patient-generated health records

End-stage liver disease (ESLD) is associated with cognitive impairment ranging from subtle alterations in attention to overt hepatic encephalopathy that resolves after transplant. Natural language processing (NLP) may provide a useful method to assess cognitive status in this population. We identified 81 liver transplant recipients with ESLD (4/2013–2/2018) who sent at least one patient-to-provider electronic message pre-transplant and post-transplant, and matched them 1:1 to “healthy” controls—who had similar disease, but had not been evaluated for liver transplant—by age, gender, race/ethnicity, and liver disease. Messages written by patients pre-transplant and post-transplant and controls was compared across 19 NLP measures using paired Wilcoxon signed-rank tests. While there was no difference overall in word length, patients with Model for End-Stage Liver Disease Score (MELD) ≥ 30 (n = 31) had decreased word length in pre-transplant messages (3.95 [interquartile range (IQR) 3.79, 4.14]) compared to post-transplant (4.13 [3.96, 4.28], p = 0.01) and controls (4.2 [4.0, 4.4], p = 0.01); there was no difference between post-transplant and controls (p = 0.4). Patients with MELD ≥ 30 had fewer 6+ letter words in pre-transplant messages (19.5% [16.4, 25.9] compared to post-transplant (23.4% [20.0, 26.7] p = 0.02) and controls (25.0% [19.2, 29.4]; p = 0.01). Overall, patients had increased sentence length pre-transplant (12.0 [9.8, 13.7]) compared to post-transplant (11.0 [9.2, 13.3]; p = 0.046); the same was seen for MELD ≥ 30 (12.3 [9.8, 13.7] pre-transplant vs. 10.8 [9.6, 13.0] post-transplant; p = 0.050). Application of NLP to patient-generated messages identified language differences—longer sentences with shorter words—that resolved after transplant. NLP may provide opportunities to detect cognitive impairment in ESLD.

Conversational trouble and repair in dementia: Revision of an existing coding framework

A decline in the effectiveness of everyday conversation is often observed for people with dementia. This study explored conversational trouble and repair between people with dementia residing in residential care and professional care staff. The aim was to examine the utility of an existing conversational trouble and repair framework by Watson, Carter and Chenery (1999) in a comparatively larger sample. Twenty conversations were coded for dementia-specific trouble and repair; however, the original framework could not adequately accommodate the variety of trouble and repair within the dataset. The data was subsequently used to inform a revised framework, which captures a wide spectrum of trouble and repair in dementia and offers more precise codes to researchers and clinicians working with this clinical population. Examples of divergent coding strategies between the original and revised framework are provided as well as examples of trouble and repair patterns observed in both carers and people with dementia.

The Subjective Experience of Inner Speech in Aphasia Is a Meaningful Reflection of Lexical Retrieval

Purpose Individuals with aphasia often report that they feel able to say words in their heads, regardless of speech output ability. Here, we examine whether these subjective reports of successful "inner speech" (IS) are meaningful and test the hypothesis that they reflect lexical retrieval. Method Participants were 53 individuals with chronic aphasia. During silent picture naming, participants reported whether or not they could say the name of each item inside their heads. Using the same items, they also completed 3 picture-based tasks that required phonological retrieval and 3 matched auditory tasks that did not. We compared participants' performance on these tasks for items they reported being able to say internally versus those they reported being unable to say internally. Then, we examined the relationship of psycholinguistic word features to self-reported IS and spoken naming accuracy. Results Twenty-six participants reported successful IS on nearly all items, so they could not be included in the item-level analyses. These individuals performed correspondingly better than the remaining participants on tasks requiring phonological retrieval, but not on most other language measures. In the remaining group ( n = 27), IS reports related item-wise to performance on tasks requiring phonological retrieval, but not to matched control tasks. Additionally, IS reports were related to 3 word characteristics associated with lexical retrieval, but not to articulatory complexity; spoken naming accuracy related to all 4 word characteristics. Six participants demonstrated evidence of unreliable IS reporting; compared with the group, they also detected fewer errors in their spoken responses and showed more severe language impairments overall. Conclusions Self-reported IS is meaningful in many individuals with aphasia and reflects lexical phonological retrieval. These findings have potential implications for treatment planning in aphasia and for our understanding of IS in the general population.

Intraoperative linguistic performance during awake brain surgery predicts postoperative linguistic deficits

Introduction

Awake craniotomy pursues a balance between extensive tumor resection and preservation of postoperative language function. A dilemma exists in patients whose tumor resection is restricted due to signs of language impairment observed during awake craniotomy. In order to determine the degree to which recovery of language function caused by tumor resection can be achieved by spontaneous neuroplasticity, the change in postoperative language function was compared to quantified intraoperative linguistic performance.

Methods

The modified, short-form Boston Diagnostic Aphasia Examination (sfBDAE) was used to assess pre- and postoperative language functions; visual object naming (DO 80) and semantic-association (Pyramid and Palm Tree Test, PPTT) tests assessed intraoperative linguistic performance. DO 80 and PPTT were performed alternatively during subcortical functional monitoring while performing tumor resection and sfBDAE was assessed 1-week postoperatively.

Results

Most patients with observed language impairment during awake surgery showed improved language function postoperatively. Both intraoperative DO 80 and PPTT showed significant correlation to postoperative sfBDAE domain scores (p < 0.05), with a higher correlation observed with PPTT. A linear regression model showed that only PPTT predicted the postoperative sfBDAE domain scores with the adjusted R² ranging from 0.51 to 0.89 (all p < 0.01). Receiver operating characteristic analysis showed a cutoff value of PPTT that yielded a sensitivity of 80% and specificity of 100%.

Conclusion

PPTT may be a feasible tool for intraoperative linguistic evaluation that can predict postoperative language outcomes. Further studies are needed to determine the extent of tumor resection that optimizes the postoperative language following neuroplasticity.

Subjective experience of inner speech in aphasia: Preliminary behavioral relationships and neural correlates

Many individuals with aphasia describe anomia with comments like "I know it but I can't say it." The exact meaning of such phrases is unclear. We hypothesize that at least two discrete experiences exist: the sense of (1) knowing a concept, but failing to find the right word, and (2) saying the correct word internally but not aloud (successful inner speech, sIS). We propose that sIS reflects successful lexical access; subsequent overt anomia indicates post-lexical output deficits. In this pilot study, we probed the subjective experience of anomia in 37 persons with aphasia. Self-reported sIS related to aphasia severity and phonological output deficits. In multivariate lesion-symptom mapping, sIS was associated with dorsal stream lesions, particularly in ventral sensorimotor cortex. These preliminary results suggest that people with aphasia can often provide meaningful insights about their experience of anomia and that reports of sIS relate to specific lesion locations and language deficits.

The cognitive mechanisms underlying perspective taking between conversational partners: evidence from speakers with Alzheimer׳s disease

Successful communication requires speakers to consider their listeners׳ perspectives. Little is known about how this ability changes in Alzheimer׳s Disease (AD) although such knowledge could reveal the cognitive mechanisms fundamental to perspective-taking ability, and reveal which cognitive deficits are fundamental to communication disorders in AD. Patients with mild to moderate AD and age and education matched controls were tested in a communicative perspective-taking task, and on measures of executive control, general cognitive functioning, and lexical retrieval. Patients׳ ability to perform the perspective-taking task was significantly correlated with performance on measures of general cognitive functioning, visual scanning and construction, response conflict and attention. Measures of lexical retrieval tended not to be correlated with performance on the communication task with one exception: semantic but not letter fluency predicted a derived score of perspective-taking ability. These findings broaden our understanding of the cognitive mechanisms underlying perspective taking, and suggest that impairments in perspective taking in AD occur during utterance planning, and at a relatively early processing stage which involves rapid visual scanning and problem solving, rather than during retrieval of lexical items needed to speak. More broadly, these data reveal executive function and semantic deficits, but not problems with lexical retrieval, as more fundamental to the basis of cognitive changes associated with AD.

Microlinguistic aspects of the oral narrative in patients with Alzheimer's disease

BACKGROUND

Alzheimer's disease (AD) is characterized by memory loss and cognitive impairment. Phonological, syntactic, semantic and discursive aspects of language may also be affected. Analysis of micro- and macrolinguistic abilities of discourse may assist in diagnosing AD. The aim of this study was to identify changes in the discourse (lexical errors and syntactic index) of AD patients.

METHODS

121 elderly subjects narrated a story based on a seven-figure picture description.

RESULTS

Patients with AD presented more word-finding difficulties, revisions and repetitions, and the syntactic index was lower than controls.

CONCLUSION

Performance in microlinguistics at the lexical and syntactic levels was lower than expected in participants with AD.

An analysis of communication in conversation in patients with dementia

Patients with degenerative dementia often show language disorders, but little is known about their verbal (VC) and non-verbal communication (NVC). Our aim was to analyse VC and NVC in patients with standard criteria of mild-moderately severe dementia (MMSE ≥14/30) resulting from Alzheimer's disease (AD; 29 cases), behavioural variant of frontotemporal dementia (FTD; 16), or dementia with Lewy bodies (DLB; 13). We used the Lille Communication Test, which addresses three domains: participation in communication (PC: greeting, attention, participation), VC (verbal comprehension, speech outflow, intelligibility, word production, syntax, verbal pragmatics and verbal feedback), and NVC (understanding gestures, affective expressivity, producing gestures, pragmatics and feedback). Patients were compared with 47 matching control subjects. AD patients were partially impaired (p≤0.01) in PC (greeting), and more definitely in VC, especially by verbal comprehension and word finding difficulties and to a much lesser degree in verbal pragmatics (responding to open questions, presenting new information), while NVC was mostly preserved. FTD patients were severely impaired in PC. VC difficulties were related to lexical-semantic, syntactic and more specifically pragmatic problems. NVC was impaired by difficulties in affective expressivity, pragmatics and feedback management. DLB patients showed modest difficulties with VC. PC, VC and NVC strongly correlated with performance in the dementia rating scale. In conclusion, the profile of communication difficulties was quite different between groups. FTD patients showed most severe difficulties in PC and verbal and non-verbal pragmatics, in relation to their frontal lesions. AD patients had prominent impairment of lexical-semantic operations.

Temporal parameters of spontaneous speech in Alzheimer's disease

This paper reports on four temporal parameters of spontaneous speech in three stages of Alzheimer's disease (mild, moderate, and severe) compared to age-matched normal controls. The analysis of the time course of speech has been shown to be a particularly sensitive neuropsychological method to investigate cognitive processes such as speech planning and production. The following parameters of speech were measured in Hungarian native-speakers with Alzheimer's disease and normal controls: articulation rate, speech tempo, hesitation ratio, and rate of grammatical errors. Results revealed significant differences in most of these speech parameters among the three Alzheimer's disease groups. Additionally, the clearest difference between the normal control group and the mild Alzheimer's disease group involved the hesitation ratio, which was significantly higher in the latter group. This parameter of speech may have diagnostic value for mild-stage Alzheimer's disease and therefore could be a useful aid in medical practice.

Improvement of spontaneous speech in early stage Alzheimer's with rivastigmine

OBJECTIVES

Placebo-controlled trials have shown that rivastigmine can delay cognitive deterioration in patients with mild to moderate Alzheimer's disease (AD). Benefits on cognitive functioning, as measured with the ADAS-Cog, occur on a daily dose of 6-12 mg when used for at least 6 months. The effect of rivastigmine on the adequacy of spontaneous speech is unknown. This study aimed to (i) compare the spontaneous speech of AD patients with the spontaneous speech of persons with normal cognition, (ii) compare the spontaneous speech of the same group of AD patients before and after treatment with rivastigmine.

METHODS

Spontaneous speech of AD patients (n=9) was compared with that of healthy elderly volunteers (n=8). In the patient group, spontaneous speech was analysed before and after treatment with rivastigmine.

RESULTS

Before treatment, 100% discrimination was found between the spontaneous speech of AD patients and of healthy volunteers based on two linguistic parameters: empty words and compound sentences. After treatment with rivastigmine the spontaneous speech of the AD patients improved on these two variables, while the ADAS-Cog scores decreased. Mean interval between the two spontaneous speech samples was 8.89 months.

CONCLUSION

Assessment of spontaneous speech might be a valid parameter to discriminate between normal cognition and AD, and to evaluate the effects of anti-AD medication.

Verb acquisition and representation in Alzheimer's disease

We examined the implicit acquisition and mental representation of a novel verb in patients with probable Alzheimer's disease (AD). Patients were exposed to the new verb in a naturalistic manner as part of a simple picture story. We probed grammatical, semantic and thematic matrix knowledge of the verb soon after presentation and again 1 week later. We found partial verb acquisition that was retained over 1 week. AD patients did not differ from controls in their acquisition and retention of a new verb's major grammatical subcategory, although they acquired little of its semantic properties and displayed minimal acquisition of the new word's thematic matrix. Moreover, AD patients appeared to maintain their acquired grammatical knowledge over 1 week. We discuss the implications of these findings from several perspectives, including the modularity of the language processing system, the relationship between episodic memory and semantic memory, and the role of the preserved implicit memory system in AD patients' partially successful lexical acquisition.

Why consider impaired social language usage in a case of corticobasal degeneration?

The purpose of this case study was to examine the integrity of cognitive skills, language usage, and language structure components in a patient with corticobasal degeneration (CBD). CBD is a levadopa-nonresponsive, degenerative neurologic movement disorder that is generally accompanied by cognitive (frontal executive dysfunction, dementia) and linguistic (aphasia) disorders. However, no one has reported on social language usage deficits in cases of CBD. The reported frontal executive dysfunction found in CBD led us to expect social language usage deficits in the present case study. Consistent with the literature, the patient demonstrated motor, cognitive (severe apraxia, frontal executive deficits, dementia), and linguistic deficits (aphasia). However she also demonstrated significantly abnormal social language usage previously unreported in the literature.

Pragmatic skills in the early stages of Alzheimer's disease: an analysis by means of a referential communication task

BACKGROUND

Disordered discourse in cases of senile dementia of Alzheimer's type (DAT) has mainly been described in conversation and picture description tasks. The referential communication task provides researchers and clinicians with new insights on the nature of these disorders.

AIMS

To study to what extent persons suffering from DAT can benefit from shared experience through trial repetition to achieve common reference.

METHODS & PROCEDURES

Thirteen persons suffering from DAT at minimal or mild stage (MMSE score range = 18-27) were compared with 13 healthy elderly adults (64-86 years) in neuropsychological assessment of executive functions and in a referential communication paradigm. To study how the two partners achieve mutual understanding by progressively elaborating a common ground, the task was repeated three times.

OUTCOMES & RESULTS

Persons with DAT produced a larger number of words than control participants and they benefited from the task repetition. However, they were less able to take into account previously shared information, used no definite referential expressions and were more idiosyncratic in their descriptions of the referent. This decline of communicative effectiveness was found not to relate closely to executive deficits.

CONCLUSIONS

Collaborative exchanges allow healthy elderly persons to ground reference in common experience. This process is severely disturbed in persons with DAT, in relation to poor memory of preceding episodes or to other cognitive impairments.

Qualitative neuropsychological performance characteristics in frontotemporal dementia and Alzheimer's disease

BACKGROUND

Frontotemporal dementia (FTD) and Alzheimer's disease are clinically distinct disorders, yet neuropsychological studies have had variable success in distinguishing them. A possible reason is that studies typically rely on overall accuracy scores, which may obscure differences in reasons for failure.

OBJECTIVES

To explore the hypothesis that analysis of qualitative performance characteristics and error types, in addition to overall numerical scores, would enhance the neuropsychological distinction between FTD and Alzheimer's disease.

METHODS

38 patients with FTD and 73 with Alzheimer's disease underwent assessment of language, visuospatial abilities, memory, and executive function, using a neuropsychological screening instrument and standard neuropsychological tests. In each of these cognitive domains, performance characteristics and error types were documented, in addition to numerical scores on tests.

RESULTS

Whereas comparison of neuropsychological test scores revealed some group differences, these did not occur consistently across tests within cognitive domains. However, analysis of performance characteristics and error types revealed qualitative differences between the two groups. In particular, FTD patients displayed features associated with frontal lobe dysfunction, such as concrete thought, perseveration, confabulation, and poor organisation, which disrupted performance across the range of neuropsychological tests.

CONCLUSIONS

Numerical scores on neuropsychological tests alone are of limited value in differentiating FTD and Alzheimer's disease, but performance characteristics and error types enhance the distinction between the two disorders. FTD is associated with a profound behavioural syndrome that affects performance on cognitive assessment, obscuring group differences. Qualitative information should be included in neuropsychological research and clinical assessments.

Verb deficits in Alzheimer's disease and agrammatism: implications for lexical organization

This study examined the nature of verb deficits in 14 individuals with probable Alzheimer's Disease (PrAD) and nine with agrammatic aphasia. Production was tested, controlling both semantic and syntactic features of verbs, using noun and verb naming, sentence completion, and narrative tasks. Noun and verb comprehension and a grammaticality judgment task also were administered. Results showed that while both PrAD and agrammatic subjects showed impaired verb naming, the syntactic features of verbs (i.e., argument structure) influenced agrammatic, but not Alzheimer's disease patients' verb production ability. That is, agrammatic patients showed progressively greater difficulty with verbs associated with more arguments, as has been shown in previous studies (e.g., Kim & Thompson, 2000; Thompson, 2003; Thompson, Lange, Schneider, & Shapiro, 1997), and suggest a syntactic basis for verb production deficits in agrammatism. Conversely, the semantic complexity of verbs affected PrAD, but not agrammatic, patients' performance, suggesting "bottom-up" breakdown in their verb lexicon, paralleling that of nouns, resulting from the degradation or loss of semantic features of verbs.

Cognitive resources during sentence processing in Alzheimer's disease

This study assessed sentence comprehension in Alzheimer's disease (AD) while minimizing executive resource demands. AD patients (n=17) and healthy elderly control subjects (n=17) were asked to detect a word in a sentence. Unbeknownst to subjects, the target word at times followed an incorrect grammatical or semantic agreement. Control subjects took significantly longer to respond to a target word when it immediately followed an agreement violation compared to a coherent agreement, a difference that was not evident when the target word followed the agreement by several syllables. AD patients did not demonstrate a discrepancy between a violation and a coherent agreement in the immediate vicinity of the agreement, but demonstrated a significant delay in their response to a target word when it followed an agreement violation--particularly a violation of a grammatical agreement--by several syllables. Analyses of individual patient performance profiles revealed the pattern of delayed sensitivity to agreements in a majority of AD patients. Correlation and regression analyses associated AD patients' sensitivity to agreement violations over an abnormally delayed time course with a measure of inhibitory control, although weaker associations were also evident with measures of planning and short-term memory. We hypothesize that difficulty understanding grammatically complex sentences in AD is related to slowed information processing speed that restricts the timely construction of a sentence's structure and limits inhibition of canonical sentence interpretations such as first-noun-is-subject.

Phonological and articulatory impairment in Alzheimer's disease: a case series

We demonstrate that phonological and articulatory impairments may occur at presentation or early in the course of Alzheimer's disease, contrary to claims that these aspects of language production are relatively preserved until the final stages of this disease. Six patients with pathologically confirmed Alzheimer's disease (AD) and four patients with clinically diagnosed dementia of the Alzheimer's type (DAT) presented with one of five different clinical profiles: nonfluent progressive aphasia, mixed progressive aphasia, progressive aphasia diagnosed as DAT from neuropsychological assessment, initial amnestic syndrome with prominent phonological errors, and biparietal syndrome. Analysis of their conversational speech, single-word production, and performance of highly familiar series speech tasks such as counting revealed false start errors, phonological paraphasias, and/or articulatory difficulty. Neuropathological changes were located in left perisylvian regions consistent with speech and language impairment but atypical for Alzheimer's disease.

Cognitive mechanisms for processing nonwords: evidence from Alzheimer's disease

Repetition and reading of various types of pronounceable nonwords (pseudowords) was examined in patients with probable Alzheimer's disease (AD) and healthy elderly controls. Overall accuracy of performance was lower in AD patients compared to controls, but the two groups showed qualitatively similar response patterns when reading different kinds of pseudowords aloud and when repeating pseudowords composed of familiar phonological forms, analogous to those in real English words. AD patients diverged in performance from controls, however, when repeating pseudowords composed of phonologically unusual forms. These results support two conclusions: (1) Aspects of phonological processing may become disrupted in AD patients in association with increasing dementia severity, while orthographic processing remains comparatively less impaired. (2) The results are consistent with the view that the processing of pseudowords is achieved through the same system as real words, and further show that the influence of prior language experience on the processing of novel linguistic forms occurs primarily at the level of phonological, rather than orthographic processing.

Sentence comprehension in Alzheimer's disease

We asked 22 patients with Alzheimer's disease (AD) to respond to simple probes of sentences where we manipulated grammatical factors, semantic factors, and cognitive resource demands associated with a sentence. The results demonstrated limitations in the cognitive resources needed to appreciate atypical syntactic-thematic mapping relations and difficulty processing selection restrictions associated with a verb. By comparison, comprehension in AD was not influenced by the active or passive voice of a sentence. These findings are consistent with the hypothesis that impaired sentence comprehension in AD is multifactorial in nature, including difficulty processing cognitive resource and semantic aspects of sentences.

Spoken language of individuals with mild fluent aphasia under focused and divided-attention conditions

The spoken language of individuals with mild aphasia and age-matched control subjects was studied under conditions of isolation, focused attention, and divided attention. A picture-description task was completed alone and in competition with a tone-discrimination task. Regardless of condition, individuals with aphasia performed more poorly on most morphosyntactic, lexical, and pragmatic measures of spoken language than control subjects. Increasing condition complexity resulted in little quantitative or qualitative change in the spoken language of the control group. In contrast, the individuals with aphasia showed dual-task interference; as they shifted from isolation to divided-attention conditions, they produced fewer syntactically complete and complex utterances, fewer words, and poorer word-finding accuracy. In pragmatic terms, their communication was considered less successful and less efficient. These results suggest that decrements of attentional capacity or its allocation may negatively affect the quantity and quality of the spoken language of individuals with mild aphasia.

Repetition of single words and nonwords in Alzheimer's disease

Repetition of single words and pronounceable nonwords (pseudowords) was assessed in Alzheimer's Disease (AD) patients to evaluate how lexical phonological processing might be accomplished when semantic and conceptual knowledge is impaired. AD patients performed significantly worse than healthy elderly controls on all repetition tasks. However, repetition abilities and dementia severity were not correlated, and AD patients produced the same distribution of error types as controls. Furthermore, despite their semantic problems, AD patients, like controls, showed a significant advantage for repeating real words compared to pseudowords, even when repeating low frequency phonologically complex words whose meaning is not likely to have been retained. The results support the postulated existence of a lexical phonological system that is used to repeat both known and novel words and that processes linguistic information independent of its meaning.

Lexical acquisition in probable Alzheimer's disease

Patients with probable Alzheimer's disease (pAD) were exposed to a new verb in a naturalistic fashion. We probed their knowledge of the word's semantic and grammatical characteristics for several minutes following this exposure, and compared this with their performance on parallel measures assessing known words. Significant differences were seen between pAD patients and controls in the acquisition of the new verb's semantic meaning and its argument structure, but pAD patients did not differ from controls in the acquisition of the new word's grammatical form class. Individual patient analyses demonstrated parallel deficits restricted to the semantic meaning and argument structure of the new word and known words in several pAD patients, suggesting that a selective language impairment contributed to their word learning deficit. This pattern is consistent with an intimate relationship between semantic meaning and argument structure in semantic memory. Other pAD patients had difficulty learning about all aspects of the new word, despite good performance with known words, suggesting that compromised memory may have limited their lexical acquisition.

Discourse topic management in senile dementia of the Alzheimer's type

The purpose of the study was to provide a detailed evaluation of the topic management abilities of a group of subjects with senile dementia of the Alzheimer's type (SDAT) and to compare their patterns of topic management to that of a normal elderly (NE) subject group. Twenty-four subjects participated in the study: 12 SDAT subjects and 12 NE subjects matched along the variables of age, sex, and education. The evaluation of topic management was based on a 20-minute casual conversational interaction between the subject and a speech-language pathologist that was videotaped and later transcribed orthographically. Topic management was analyzed in terms of a modified version of the multidimensional topic coherence analysis developed by Mentis and Prutting (1991). The results indicated significant differences between the SDAT and NE subjects along a number of parameters of topic introduction and maintenance. The topic management profiles of the SDAT subjects were characterized by a reduced ability to change topics while preserving the discourse flow, difficulty in actively contributing to the propositional development of the topic, and a failure to consistently maintain topic in a clear and coherent manner. These problems appeared to be related to underlying problems across the discourse-pragmatic, linguistic, and cognitive domains; they highlight the need to more fully explore the interactions among deficits in SDAT and their effects on conversational discourse.

An aspect of sentence processing in Alzheimer's disease: quantifier-noun agreement

We assessed sentence processing in Alzheimer's disease (AD) with measures of sentence-picture matching, grammaticality judgments of sentences, and sentence completion. The results demonstrated significant and consistent difficulty with a grammatical feature of sentences on all three experiments. This impairment could not be explained by factors such as sentence length, dementia severity, or a short-term memory deficit and was independent of difficulty interpreting the meanings of words. We hypothesize that AD patients are impaired at appreciating the conceptual relations that underlie certain grammatical features of sentences.

Importance of basic and applied research from the viewpoints of investigators in the psychology of aging

In this series of presentations, the importance and practical implications of many different research programs in the psychology of aging is presented from the viewpoints of the investigators themselves. These scientists discuss the implications and significance of their work for society as it affects other scientists, policy-makers, the media, and the public. The discussions make clear that the many of the problems associated with aging are essentially behavioral problems which can be prevented through behavioral change in the early as well as later years of the lifespan.