Semantic interference affects speech production by increasing disfluencies, not errors

Several studies have shown that different types of disfluency occur depending on the language production stage at which people experience difficulties. The current study combined a network task and a picture-word interference task to analyse whether lexical-semantic difficulty triggers errors and disfluencies in connected-speech production. The participants produced more disfluencies in the presence of a semantically related distractor word than an unrelated distractor word, while few semantic errors were made. These results support the hypothesis that difficulties at distinct stages of language production lead to distinct patterns of disfluency, with lexical-semantic difficulties leading to self-corrections and silent pauses. The results also have implications for the role of the monitoring system in connected-speech production.

Laryngeal Imaging Study of Glottal Attack/Offset Time in Adductor Spasmodic Dysphonia during Connected Speech

Adductor spasmodic dysphonia (AdSD) disrupts laryngeal muscle control during speech and, therefore, affects the onset and offset of phonation. In this study, the goal is to use laryngeal high-speed videoendoscopy (HSV) to measure the glottal attack time (GAT) and glottal offset time (GOT) during connected speech for normophonic (vocally normal) and AdSD voices. A monochrome HSV system was used to record readings of six CAPE-V sentences and part of the "Rainbow Passage" from the participants. Three raters visually analyzed the HSV data using a playback software to measure the GAT and GOT. The results show that the GAT was greater in the AdSD group than in the normophonic group; however, the clinical significance of the amount of this difference needs to be studied further. More variability was observed in both GATs and GOTs of the disorder group. Additionally, the GAT and GOT time series were found to be nonstationary for the AdSD group while they were stationary for the normophonic voices. This study shows that the GAT and GOT measures can be potentially used as objective markers to characterize AdSD. The findings will potentially help in the development of standardized measures for voice evaluation and the accurate diagnosis of AdSD.

The Discourse Profile in Corticobasal Syndrome: A Comprehensive Clinical and Biomarker Approach

The aim of this study was to characterize the oral discourse of CBS patients and to verify whether measures obtained during a semi-spontaneous speech production could differentiate CBS patients from controls. A second goal was to compare the performance of patients with CBS probably due to Alzheimer's disease (CBS-AD) pathology and CBS not related to AD (CBS-non-AD) in the same measures, based on the brain metabolic status (FDG-PET) and in the presence of amyloid deposition (amyloid-PET). Results showed that CBS patients were significantly different from controls in speech rate, lexical level, informativeness, and syntactic complexity. Discursive measures did not differentiate CBS-AD from CBS-non-AD. However, CBS-AD displayed more lexical-semantic impairments than controls, a profile that is frequently reported in patients with clinical AD and the logopenic variant of primary progressive aphasia (lvPPA). CBS-non-AD presented mainly with impairments related to motor speech disorders and syntactic complexity, as seen in the non-fluent variant of PPA.

Anterior connectivity critical for recovery of connected speech after stroke

Connected speech recovers to different degrees across people after left hemisphere stroke, but white matter predictors of differential recovery from the acute stage of stroke are unknown. We assessed changes in lexical-syntactic aspects of connected speech in a longitudinal analysis of 40 individuals (18 females) from the acute stage of left hemisphere stroke (within an average of 4 days post-stroke) to subacute (within 2 months) and chronic stages (early: 6 months, late: 1 year) while measuring the extent of acute lesions on white matter tracts to identify tracts predictive of recovery. We found that acute damage to the frontal aslant tract led to a decreased recovery of the fluency and structural complexity of connected speech during the year following left hemisphere stroke. The results were independent of baseline performance, overall lesion volume and the proportion of damage to tract-adjacent grey matter. This longitudinal analysis from acute to chronic stroke provides the first evidence that recovery of fluent and structurally complex spontaneous connected speech requires intact left frontal connectivity via the frontal aslant tract. That the frontal aslant tract was critical for recovery at early as well as later stages of stroke demonstrates that anterior connectivity plays a lasting and important role for the reorganization of function related to the successful production of connected speech.

An efficient, accurate and clinically-applicable index of content word fluency in Aphasia

Background

Despite the clinical importance of assessing the efficiency and accuracy of fluency in terms of content words production during connected speech, assessments based on discourse tasks are very time-consuming and thus not clinically feasible.

Aims

(1) Examine the relationship between single-word naming and word retrieval during discourse production. (2) Investigate the relationship between word retrieval and content word fluency derived from a simple versus naturalistic discourse tasks. (3) Develop and validate an efficient and accurate index of content word fluency that is clinically viable.

Methods

Two discourse tasks (simple picture description and naturalistic storytelling narrative) were collected from 46 participants with post-stroke aphasia, and 20 age/education matched neuro-typical controls. Each discourse sample was fully transcribed and quantitative analysis was applied to each sample to measure word retrieval and content word fluency. Three single-word naming tasks were also administered to each participant with aphasia.

Results

Correlational analyses between single-word naming and word retrieval in connected speech revealed weak/moderate relationships. Conversely, strong correlations were found between measures derived from simple picture description against naturalistic storytelling discourse tasks. Moreover, we derived a novel, transcription-less index of content word fluency from the discourse samples of an independent group (neuro-typical controls), and then we validated this index across two discourse tasks in the tested group (persons with aphasia). Correlation and regression analyses revealed extremely strong relationships between participants' (neuro-typical controls and persons with aphasia) scores on the novel index and measures of content word fluency derived from the formal transcription and quantitative analyses of discourse samples, indicating high accuracy and validity of the new index.

Conclusions

Simple picture description rather than picture naming provides a better estimate of word retrieval in naturalistic connected speech. The novel developed index is transcription-less and can be implemented online to provide an accurate and efficient measure of content word fluency. Thus, it is viable during clinical practice for assessment purposes, and possibly as an outcome measure to monitor therapy effectiveness, which can also be used in randomised clinical trials.

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.

Description of connected speech across different elicitation tasks in the logopenic variant of primary progressive aphasia

BACKGROUND

Despite its importance, in-depth analysis of connected speech is often neglected in the diagnosis of primary progressive aphasia (PPA) - especially for the logopenic variant (lvPPA) for which unreliable differential diagnosis has been documented. Only a few studies have been conducted on this topic in lvPPA.

AIMS

The aim of this study was to describe and compare lexico-semantic and morphosyntactic features of connected speech in participants with lvPPA, in comparison with healthy controls, using three different elicitation tasks (i.e., picture description, story narration and semi-structured interviews). In addition to a number of discourse features, we were particularly interested in the presence or absence of syntactic deficits in this PPA variant in line with recent findings.

METHODS & PROCEDURES

A prospective group study was conducted to compare lvPPA participants (n = 13) to age- and education-matched healthy controls (n = 13). For each individual, connected speech was obtained using three tasks: (1) The Cookie Theft picture description; (2) Cinderella Story; (3) Topic-directed interview. Production on each task was recorded, transcribed and analysed according to the Quantitative Production Analysis (QPA) protocol, a tool developed by Berndt et al. (2000) for the analysis of sentence production in aphasia. Differences between lvPPA and healthy controls and among elicitation tasks were analysed using repeated measures multilevel mixed-effects regression, separately for each outcome.

OUTCOMES & RESULTS

Four measures were significantly different between lvPPA participants and healthy controls across all elicitation tasks. Specifically, lvPPA participants produced a reduced proportion of open-class words, a higher proportion of verbs, a higher proportion of pronouns and fewer well-formed sentences. For these measures, the difference between lvPPA and healthy controls was consistent among elicitation tasks, except for the proportion of well-formed sentences, where the difference between the two groups was significantly greater in the story narration task than in the other tasks.

CONCLUSIONS & IMPLICATIONS

Across elicitation tasks that used the same analysis protocol (i.e., QPA), a similar pattern of deficits in connected speech emerged in lvPPA patients. Importantly, the findings replicate previous studies, which used different elicitation tasks and analysis protocols. Especially in relation to the documented syntactic deficits, these findings provide implications for differential diagnosis in PPA.

WHAT THIS PAPER ADDS

What is already known on the subject Connected speech analysis can provide an important contribution to the language assessment for the logopenic variant of primary progressive aphasia (lvPPA). However, only a few studies have been conducted with this population. What this paper adds to existing knowledge This study highlights differences between patients with lvPPA and healthy controls regarding the proportion of open-class words, nouns, verbs and well-formed sentences. What are the potential or actual clinical implications of this work? Importantly, our results highlight syntactic deficits in the same group of individuals with lvPPA, using the same analysis protocol and across various elicitation tasks, which has implications for differential diagnosis.

Telltale silence: temporal speech parameters discriminate between prodromal dementia and mild Alzheimer's disease

This study presents a novel approach for the early detection of mild cognitive impairment (MCI) and mild Alzheimer's disease (mAD) in the elderly. Participants were 25 elderly controls (C), 25 clinically diagnosed MCI and 25 mAD patients, included after a clinical diagnosis validated by CT or MRI and cognitive tests. Our linguistic protocol involved three connected speech tasks that stimulate different memory systems, which were recorded, then analyzed linguistically by using the PRAAT software. The temporal speech-related parameters successfully differentiate MCI from mAD and C, such as speech rate, number and length of pauses, the rate of pause and signal. Parameters pauses/duration and silent pauses/duration linearly decreased among the groups, in other words, the percentage of pauses in the total duration of speech continuously grows as dementia progresses. Thus, the proposed approach may be an effective tool for screening MCI and mAD.

How many words make a sample? Determining the minimum number of word tokens needed in connected speech samples for child speech assessment

Connected speech (CS) is an important component of child speech assessment in both clinical practice and research. There is debate in the literature regarding what size sample of CS is required to facilitate reliable measures of speech output. The aim of this study was to identify the minimum number of word tokens required to obtain a reliable measure of CS across a range of measures. Participants were 776 5-year-olds from a longitudinal community population cohort study (Avon Longitudinal Study of Parents and Children, ALSPAC). Children's narratives from a story retell task were audio-recorded and phonetically transcribed. Automatic analysis of the transcribed speech samples was completed using an automated transcription and analysis system. Measures of speech performance extracted included: a range of profiles of percentage consonant correct; frequency of substitutions, omissions, distortions and additions (SODA); percentage of syllable and stress pattern matches; and a measure of whole word complexity (Phonological Mean Length of Utterance, pMLU). Statistical analyses compared these measures at different CS sample sizes in increments using averages and weighted moving averages, and investigated how measures performed between CS samples grouped into word tokens of at least 50, 75 and 100, and restricted to samples of 50-74, 75-99 and 100-125. Key findings showed that sample sizes of 75 word tokens and above showed minimal differences in most measures of speech output, suggesting that the minimum requirement for samples of CS is a word count of 75. The exception to this is in the case of pMLU and measures of substitutions and distortions when a word count of 100 is recommended.

Amyloid beta associations with connected speech in cognitively unimpaired adults

INTRODUCTION

Connected speech and language (CSL) decline has been associated with early cognitive decline, but associations between CSL and Alzheimer's disease (AD) biomarkers remain a gap in the literature. Our goal was to examine associations with amyloid beta (Aβ) and longitudinal CSL trajectories in cognitively unimpaired adults at increased AD risk.

METHODS

Using data from the Wisconsin Registry for Alzheimer's Prevention, CSL measures were automatically extracted from digitally recorded picture descriptions. Positron emission tomography determined Aβ status. Linear mixed effects models assessed the interaction between age and Aβ on CSL trajectories.

RESULTS

Participants who were Aβ positive experienced more rapid decline on specific word content, when controlling for age, sex, and literacy. There were no differences between groups in lexical diversity measures over time.

DISCUSSION

These results indicate that declines in connected speech may be related to preclinical AD. CSL may be a promising, inexpensive, and easy-to-collect digital cognitive marker for AD studies.

Language Network Connectivity Increases in Early Alzheimer's Disease

Background:

Language production deficits occur early in the course of Alzheimer’s disease (AD); however, only a few studies have focused on language network’s functional connectivity in mild cognitive impairment (MCI) due to AD.

Objective:

The current study aims to uncover the extent of language alteration at the MCI stage, at a behavioral and neural level, using univariate and multivariate analyses of structural MRI and resting-state fMRI.

Methods:

Twenty-four MCI due to AD participants and 24 matched healthy controls underwent a comprehensive language evaluation, a structural T1-3D MRI, and resting-state fMRI. We performed seed-based analyses, using the left inferior frontal gyrus and left posterior temporal gyrus as seeds. Then, we analyzed connectivity between executive control networks and language network in each group. Finally, we used multivariate pattern analyses to test whether the two groups could be distinguished based on the pattern of atrophy within the language network; within the executive control networks, as well as the pattern of functional connectivity within the language network and within the executive control networks.

Results:

MCI due to AD participants had language impairment during standardized language tasks and connected-speech production. Regarding functional connectivity, univariate analyses were not able to discriminate participants, while multivariate pattern analyses could significantly predict participants’ group. Language network’s functional connectivity could discriminate MCI due to AD participants better than executive control networks. Most notably, they revealed an increased connectivity at the MCI stage, positively correlated with language performance.

Conclusion:

Multivariate analyses represent a useful tool for investigating the functional and structural (re-)organization of the neural bases of language.

Creating a Theoretical Framework to Underpin Discourse Assessment and Intervention in Aphasia

Discourse (a unit of language longer than a single sentence) is fundamental to everyday communication. People with aphasia (a language impairment occurring most frequently after stroke, or other brain damage) have communication difficulties which lead to less complete, less coherent, and less complex discourse. Although there are multiple reviews of discourse assessment and an emerging evidence base for discourse intervention, there is no unified theoretical framework to underpin this research. Instead, disparate theories are recruited to explain different aspects of discourse impairment, or symptoms are reported without a hypothesis about the cause. What is needed is a theoretical framework that would clarify the specific linguistic skills that create completeness, coherence, and complexity (i.e., richness) in discourse, and illuminate both the processes involved in discourse production and the reasons for breakdown. This paper reports a review and synthesis of the theoretical literature relevant to spoken discourse in aphasia discourse, and we propose a novel theoretical framework which unites these disparate sources. This framework is currently being tested as the foundation for Linguistic Underpinnings of Narrative in Aphasia (LUNA) treatment research. In this paper, we outline the novel framework and exemplify how it might be used to guide clinical practice and research. Future collaborative research is needed to develop this framework into a processing model for spoken discourse.

A Hybrid Machine-Learning-Based Method for Analytic Representation of the Vocal Fold Edges during Connected Speech

Investigating the phonatory processes in connected speech from high-speed videoendoscopy (HSV) demands the accurate detection of the vocal fold edges during vibration. The present paper proposes a new spatio-temporal technique to automatically segment vocal fold edges in HSV data during running speech. The HSV data were recorded from a vocally normal adult during a reading of the “Rainbow Passage.” The introduced technique was based on an unsupervised machine-learning (ML) approach combined with an active contour modeling (ACM) technique (also known as a hybrid approach). The hybrid method was implemented to capture the edges of vocal folds on different HSV kymograms, extracted at various cross-sections of vocal folds during vibration. The k-means clustering method, an ML approach, was first applied to cluster the kymograms to identify the clustered glottal area and consequently provided an initialized contour for the ACM. The ACM algorithm was then used to precisely detect the glottal edges of the vibrating vocal folds. The developed algorithm was able to accurately track the vocal fold edges across frames with low computational cost and high robustness against image noise. This algorithm offers a fully automated tool for analyzing the vibratory features of vocal folds in connected speech.

Connected Speech Deficit as an Early Hallmark of CSF-defined Alzheimer's Disease and Correlation with Cerebral Hypoperfusion Pattern

BACKGROUND

Diagnosis of prodromal Alzheimer's disease (AD) still represents a hot topic and there is a growing interest for the detection of early and non-invasive biomarkers. Although progressive episodic memory impairment is the typical predominant feature of AD, communicative difficulties can be already present at the early stages of the disease.

OBJECTIVE

This study investigated the narrative discourse production deficit as a hallmark of CSFdefined prodromal AD and its correlation with cerebral hypoperfusion pattern.

METHODS

Narrative assessment with a multilevel procedure for discourse analysis was conducted on 28 subjects with Mild Cognitive Impairment (15 MCI due to AD; 13 MCI non-AD) and 28 healthy controls. The diagnostic workup included CSF AD biomarkers. Cerebral hypoperfusion pattern was identified by SPECT image processing.

RESULTS

The results showed that the discourse analysis of global coherence and lexical informativeness indexes allowed to identify MCI due to AD from MCI non-AD and healthy subjects. These findings allow to hypothesize that the loss of narrative efficacy could be a possible early clinical hallmark of Alzheimer's disease. Furthermore, a significant correlation of global coherence and lexical informativeness reduction with the SPECT hypoperfusion was found in the dorsal aspect of the anterior part of the left inferior frontal gyrus, supporting the hypothesis that this area has a significant role in communicative efficacy, and in particular, in semantic selection executive control.

CONCLUSION

This study contributes to the understanding of the neural networks for language processing and their involvement in prodromal Alzheimer's disease. It also suggests an easy and sensitive tool for clinical practice that can help identifying individuals with prodromal Alzheimer's disease.

Word-finding in confrontation naming and picture descriptions produced by individuals with early post-stroke aphasia

OBJECTIVE

The present study aims to assess the relationship between quantitative measures of connected speech production and performance in confrontation naming in early post-stroke aphasia (8-14 days post-stroke). Method: We collected connected speech samples elicited by a picture description task and administered a confrontation naming task to 20 individuals with early post-stroke aphasia and 20 healthy controls. Transcriptions were made in compliance with the CHAT format guidelines. Several micro- (i.e. duration, total number of words, words per minute, mean length of utterances, ratio of open- to closed-class words and noun-to-verb ratio, VOC-D, repetitions, self-corrections, and phonological and semantic errors) and macrolinguistic (i.e. informativeness and efficiency) measures were extracted. Results: We provide evidence for the presence of impairments in an array of micro- and macrolinguistic measures of speech in individuals with early post-stroke aphasia. We show that in the patient group, confrontation naming abilities most strongly relate to informativeness in a picture description task. Conclusion: Our findings contribute to a better understanding of the relationship between performance in confrontation naming and in connected speech production in the first days after stroke onset and also suggest that discourse analysis may provide unique, possibly more complex information.

Dissociation between frontal and temporal-parietal contributions to connected speech in acute stroke

Humans are uniquely able to retrieve and combine words into syntactic structure to produce connected speech. Previous identification of focal brain regions necessary for production focused primarily on associations with the content produced by speakers with chronic stroke, where function may have shifted to other regions after reorganization occurred. Here, we relate patterns of brain damage with deficits to the content and structure of spontaneous connected speech in 52 speakers during the acute stage of a left hemisphere stroke. Multivariate lesion behaviour mapping demonstrated that damage to temporal-parietal regions impacted the ability to retrieve words and produce them within increasingly complex combinations. Damage primarily to inferior frontal cortex affected the production of syntactically accurate structure. In contrast to previous work, functional-anatomical dissociations did not depend on lesion size likely because acute lesions were smaller than typically found in chronic stroke. These results are consistent with predictions from theoretical models based primarily on evidence from language comprehension and highlight the importance of investigating individual differences in brain-language relationships in speakers with acute stroke.

Variation in language mixing in multilingual aphasia

Mixing languages within a sentence or a conversation is a common practice among many speakers of multiple languages. Language mixing found in multilingual speakers with aphasia has been suggested to reflect deficits associated with the brain lesion. In this paper, we examine language mixing behaviour in multilingual people with aphasia to test the hypothesis that the use of language mixing reflects a communicative strategy. We analysed connected language production elicited from 11 individuals with aphasia. Words produced were coded as mixed or not. Frequencies of mixing were tabulated for each individual in each of her or his languages in each of two elicitation tasks (Picture sequence description, Narrative production). We tested the predictions that there would be more word mixing: for participants with greater aphasia severity; while speaking in a language of lower post-stroke proficiency; during a task that requires more restricted word retrieval; for people with non-fluent aphasia, while attempting to produce function words (compared to content words); and that there would be little use of a language not known to the interlocutors. The results supported three of the five predictions. We interpret our data to suggest that multilingual speakers with aphasia mix words in connected language production primarily to bypass instances of word-retrieval difficulties, and typically avoid pragmatically inappropriate language mixing.

Connected speech and language in mild cognitive impairment and Alzheimer's disease: A review of picture description tasks

INTRODUCTION

The neuropsychological profile of people with mild cognitive impairment (MCI) and Alzheimer's disease (AD) dementia includes a history of decline in memory and other cognitive domains, including language. While language impairments have been well described in AD dementia, language features of MCI are less well understood. Connected speech and language analysis is the study of an individual's spoken discourse, usually elicited by a target stimulus, the results of which can facilitate understanding of how language deficits typical of MCI and AD dementia manifest in everyday communication. Among discourse genres, picture description is a constrained task that relies less on episodic memory and more on semantic knowledge and retrieval, within the cognitive demands of a communication context. Understanding the breadth of evidence across the continuum of cognitive decline will help to elucidate the areas of strength and need in terms of using this method as an evaluative tool for both cognitive changes and everyday functional communication.

METHOD

We performed an extensive literature search of peer-reviewed journal articles that focused on the use of picture description tasks for evaluating language in persons with MCI or AD dementia. We selected articles based on inclusion and exclusion criteria and described the measures assessed, the psychometric properties that were reported, the findings, and the limitations of the included studies.

RESULTS

36 studies were selected and reviewed. Across all 36 studies, there were 1, 127 patients with AD dementia and 274 with MCI or early cognitive decline. Multiple measures were examined, including those describing semantic content, syntactic complexity, speech fluency, vocal parameters, and pragmatic language. Discriminant validity widely reported and distinct differences in language were observable between adults with dementia and controls; fewer studies were able to distinguish language differences between typically aging adults and those with MCI.

DISCUSSION

Our review shows that picture description tasks are useful tools for detecting differences in a wide variety of language and communicative measures. Future research should expand knowledge about subtle changes to language in preclinical AD and Mild Cognitive Impairment (MCI) which may improve the utility of this method as a clinically meaningful screening tool.

Oral and written picture description in individuals with aphasia

BACKGROUND

Aphasia is characterized by difficulties in connected speech/writing.

AIMS

To explore the differences between the oral and written description of a picture in individuals with chronic aphasia (IWA) and healthy controls. Descriptions were controlled for productivity, efficiency, grammatical organization, substitution behaviour and discourse organization.

METHODS & PROCEDURES

Fifty IWA and 50 healthy controls matched for age, gender and education provided an oral and written description of a black-and-white situational drawing from the Dutch version of the Comprehensive Aphasia Test. Between- and within-group analyses were carried out and the reliability of the test instrument was assessed.

OUTCOMES & RESULTS

The language samples of the healthy controls were more elaborate, more efficient, syntactically richer, more coherent, and consisted of fewer spoken and written language errors than the samples of the IWA. Within-group comparisons showed that connected writing is more sensitive than connected speech to capture aphasic symptoms.

CONCLUSIONS & IMPLICATIONS

The analysis of both modalities (speech and writing) at the discourse level allows one to assess simultaneously micro- and macro-linguistic skills and their potential interrelations in a given IWA. Connected writing appears to be more sensitive in discriminating IWA from healthy controls than connected speech. This method for analyzing language samples should, however, be used in conjunction with other assessment tools.

Declines in Connected Language Are Associated with Very Early Mild Cognitive Impairment: Results from the Wisconsin Registry for Alzheimer's Prevention

Changes to everyday spoken language ("connected language") are evident in persons with AD dementia, yet little is known about when these changes are first detectable on the continuum of cognitive decline. The aim of this study was to determine if participants with very early, subclinical memory declines were also showing declines in connected language. We analyzed connected language samples obtained from a simple picture description task at two time points in 264 participants from the Wisconsin Registry for Alzheimer's Prevention (WRAP). In parallel, participants were classified as either "Cognitively Healthy" or "Early Mild Cognitive Impairment" based on longitudinal neuropsychological test performance. Linear mixed effects models were used to analyze language parameters that were extracted from the connected language samples using automated feature extraction. Participants with eMCI status declined faster in features of speech fluency and semantic content than those who were cognitively stable. Measures of lexical diversity and grammatical complexity were not associated with eMCI status in this group. These findings provide novel insights about the relationship between cognitive decline and everyday language, using a quick, inexpensive, and performance-based method.

An analysis of topics and vocabulary in Chinese oral narratives by normal speakers and speakers with fluent aphasia

This study analysed the topic and vocabulary of Chinese speakers based on language samples of personal recounts in a large spoken Chinese database recently made available in the public domain, i.e. Cantonese AphasiaBank ( http://www.speech.hku.hk/caphbank/search/ ). The goal of the analysis is to offer clinicians a rich source for selecting ecologically valid training materials for rehabilitating Chinese-speaking people with aphasia (PWA) in the design and planning of culturally and linguistically appropriate treatments. Discourse production of 65 Chinese-speaking PWA of fluent types (henceforth, PWFA) and their non-aphasic controls narrating an important event in their life were extracted from Cantonese AphasiaBank. Analyses of topics and vocabularies in terms of part-of-speech, word frequency, lexical semantics, and diversity were conducted. There was significant overlap in topics between the two groups. While the vocabulary was larger for controls than that of PWFA as expected, they were similar in distribution across parts-of-speech, frequency of occurrence, and the ratio of concrete to abstract items in major open word classes. Moreover, proportionately more different verbs than nouns were employed at the individual level for both speaker groups. The findings provide important implications for guiding directions of aphasia rehabilitation not only of fluent but also non-fluent Chinese aphasic speakers.

Connected Speech in Neurodegenerative Language Disorders: A Review

Language assessment has a crucial role in the clinical diagnosis of several neurodegenerative diseases. The analysis of extended speech production is a precious source of information encompassing the phonetic, phonological, lexico-semantic, morpho-syntactic, and pragmatic levels of language organization. The knowledge about the distinctive linguistic variables identifying language deficits associated to different neurodegenerative diseases has progressively improved in the last years. However, the heterogeneity of such variables and of the way they are measured and classified limits any generalization and makes the comparison among studies difficult. Here we present an exhaustive review of the studies focusing on the linguistic variables derived from the analysis of connected speech samples, with the aim of characterizing the language disorders of the most prevalent neurodegenerative diseases, including primary progressive aphasia, Alzheimer's disease, movement disorders, and amyotrophic lateral sclerosis. A total of 61 studies have been included, considering only those reporting group analysis and comparisons with a group of healthy persons. This review first analyzes the differences in the tasks used to elicit connected speech, namely picture description, story narration, and interview, considering the possible different contributions to the assessment of different linguistic domains. This is followed by an analysis of the terminologies and of the methods of measurements of the variables, indicating the need for harmonization and standardization. The final section reviews the linguistic domains affected by each different neurodegenerative disease, indicating the variables most consistently impaired at each level and suggesting the key variables helping in the differential diagnosis among diseases. While a large amount of valuable information is already available, the review highlights the need of further work, including the development of automated methods, to take advantage of the richness of connected speech analysis for both research and clinical purposes.

Rapid recovery from aphasia after infarction of Wernicke's area

BACKGROUND

Aphasia following infarction of Wernicke's area typically resolves to some extent over time. The nature of this recovery process and its time course have not been characterized in detail, especially in the acute/subacute period.

AIMS

The goal of this study was to document recovery after infarction of Wernicke's area in detail in the first 3 months after stroke. Specifically, we aimed to address two questions about language recovery. First, which impaired language domains improve over time, and which do not? Second, what is the time course of recovery?

METHODS & PROCEDURES

We used quantitative analysis of connected speech and a brief aphasia battery to document language recovery in two individuals with aphasia following infarction of the posterior superior temporal gyrus. Speech samples were acquired daily between 2 and 16 days post stroke, and also at 1 month and 3 months. Speech samples were transcribed and coded using the CHAT system, in order to quantify multiple language domains. A brief aphasia battery was also administered at a subset of five time points during the 3 months.

OUTCOMES & RESULTS

Both patients showed substantial recovery of language function over this time period. Most, but not all, language domains showed improvements, including fluency, lexical access, phonological retrieval and encoding, and syntactic complexity. The time course of recovery was logarithmic, with the greatest gains taking place early in the course of recovery.

CONCLUSIONS

There is considerable potential for amelioration of language deficits when damage is relatively circumscribed to the posterior superior temporal gyrus. Quantitative analysis of connected speech samples proved to be an effective, albeit time-consuming, approach to tracking day-by-day recovery in the acute/subacute post-stroke period.

Connected speech in transient aphasias after left hemisphere resective surgery

BACKGROUND

Transient aphasias are common in the first few days after resective surgery to the language-dominant hemisphere. The specific speech and language deficits that occur are related to the location of the surgical site, and may include impairments in fluency, lexical access, repetition, and comprehension. The impact of these transient aphasias on connected speech production has not previously been investigated.

AIMS

The goals of this study were to characterize the nature of connected speech deficits in the immediate post-surgical period, and to determine which deficits resolve completely within 1 month.

METHODS & PROCEDURES

Forty-three patients undergoing resective surgery in the left (language-dominant) hemisphere participated in the study. Brief connected speech samples were obtained before surgery, and at 2-3 days post-surgery. In a subset of 24 patients (all of whom presented with aphasia in the immediate post-surgical period), follow-up samples were also obtained at 1 month post-surgery. The samples were transcribed and coded in CHAT format. Ten connected speech measures were derived from each speech sample, and were then compared by time point.

OUTCOMES & RESULTS

At 2-3 days post surgery, deficits were observed in all 10 connected speech measures in comparison to pre-surgical samples: there were decreases in words per minute, words per utterance, and the use of embedded clauses, and increases in phonological errors, lexical access difficulties, morphosyntactic errors, filled pauses, false starts and retraced sequences. The proportion of closed class words could be perturbed in either direction. At 1 month post-surgery, 8 of the 10 connected speech measures had significantly improved, and all measures reflecting structural features (words per utterance, number of embeddings, morphosyntactic errors, proportion of words that were closed class) were equivalent to the pre-surgical time point. Subtle deficits persisted in some other measures; in particular, there were more phonological errors and lexical access difficulties than at the pre-surgical point.

CONCLUSIONS

Transient aphasias after left hemisphere surgery impacted all aspects of connected speech in the immediate post-surgical period. Most of these deficits were largely or completely resolved by 1 month post surgery, but some subtle impairments persisted.

Exploring generalisation processes following lexical retrieval intervention in primary progressive aphasia

PURPOSE

Within the current literature, positive intervention effects demonstrate the significant potential for people with Primary Progressive Aphasia (PPA) to learn/relearn words. Generalisation of intervention effects to other words and/or other contexts, however, remains unclear.

METHOD

This multiple baseline, case-series design investigated the effects of a self-cueing lexical retrieval intervention across word classes (nouns, verbs and adjectives) on four individuals with PPA, three suggestive of the semantic variant and one of the logopenic variant. The intervention integrated semantic, phonological and orthographic levels of language production and drew on autobiographical memory. Changes in accuracy in retrieving treated and untreated items (pre-intervention, post-intervention and 4-weeks maintenance) were determined using the Cochran's Q test, with follow-up McNemar pairwise comparisons.

RESULT

All participants showed significant improvements in naming treated items, across all word classes. Different patterns of generalised improvement to untreated words were found for each participant. In discourse, the semantic variant participants demonstrated a significant increase in correct information units, in contrast to the participant with the logopenic variant who remained stable.

CONCLUSION

This study provides evidence that people with PPA can show improved lexical retrieval following intervention. The findings suggest possible differences in generalisation across word classes and according to underlying deficit.

Context effects on verb production in specific language impairment (SLI): confrontation naming versus connected speech

A handful of studies have shown that verbs are more vulnerable than nouns to retrieval deficits on picture-based naming tasks for children with specific language impairment (SLI). The aim of this study was to examine if the disproportionate verb as opposed to noun production deficit reported for naming is also found in connected speech. Sixteen children participated in the study: eight children diagnosed with SLI (mean age: 6:3 years) and eight typically language developing (TLD, mean age: 5:9 years) controls. Verb and noun production was measured in connected speech and compared to picture confrontation naming. Both groups of children showed a significant difficulty naming verbs compared to nouns. In contrast, they did not differ on the total number of both verb tokens and verb types produced in connected speech. The findings indicate that the previously reported verb retrieval difficulties in SLI are a product of the confrontation naming task demands rather than a true verb deficit.

Does Discourse Congruence Influence Spoken Language Comprehension before Lexical Association? Evidence from Event-Related Potentials

The goal of this study was to examine how lexical association and discourse congruence affect the time course of processing incoming words in spoken discourse. In an ERP norming study, we presented prime-target pairs in the absence of a sentence context to obtain a baseline measure of lexical priming. We observed a typical N400 effect when participants heard critical associated and unassociated target words in word pairs. In a subsequent experiment, we presented the same word pairs in spoken discourse contexts. Target words were always consistent with the local sentence context, but were congruent or not with the global discourse (e.g., "Luckily Ben had picked up some salt and pepper/basil", preceded by a context in which Ben was preparing marinara sauce (congruent) or dealing with an icy walkway (incongruent). ERP effects of global discourse congruence preceded those of local lexical association, suggesting an early influence of the global discourse representation on lexical processing, even in locally congruent contexts. Furthermore, effects of lexical association occurred earlier in the congruent than incongruent condition. These results differ from those that have been obtained in studies of reading, suggesting that the effects may be unique to spoken word recognition.

Effect of Verb Network Strengthening Treatment (VNeST) on Lexical Retrieval of Content Words in Sentences in Persons with Aphasia

BACKGROUND: Verb Network Strengthening Treatment (VNeST) is a semantic treatment that aims to improve lexical retrieval of content words in sentence context by promoting systematic retrieval of verbs (e.g., measure) and their thematic roles (i.e., agent (doer of the action, e.g., carpenter, chef)) and patient (receiver of the action, e.g., lumber, sugar)). VNeST is influenced by Loverso and colleagues (e.g., Loverso, Selinger, and Prescott, 1979), who used "verb as core" treatment to improve sentence production with encouraging results, and McRae and colleagues, who showed that verbs prime typical agents (e.g., pray-nun) and patients (arrest-criminal) (Ferretti, McRae, & Hatherell, 2001) and vice-versa (McRae, Hare, Elman, & Ferretti, 2005). AIMS: There are four specific questions in this study. Does training a set of verbs using VNeST generalize to the ability to produce 1) an agent (carpenter), trained verb (measure), and patient (stairs) in response to novel picture stimuli and 2) an agent (nurse), untrained semantically related verb (weigh), and patient (baby) in response to novel picture stimuli? 3) Are generalization effects maintained?, and 4) Does VNeST generalize to the ability to retrieve nouns and verbs not directly related to treatment items in single word naming, picture description and connected speech tasks? METHODS #ENTITYSTARTX00026; PROCEDURES: Four participants with aphasia participated. Participants received VNeST, which involves retrieval of agent-patient pairs (e.g., chef/sugar, surveyor/land) related to trained verbs (e.g., measure), two times per week. A single subject, repeated probe, multiple baseline experimental design was used. Generalization to sentence production for sentences containing trained verbs and untrained semantically related verbs was tested weekly. OUTCOMES #ENTITYSTARTX00026; RESULTS: Results demonstrated generalization to lexical retrieval of content words in sentences with trained and untrained verbs across participants. Additionally, pre- to post-treatment generalization was observed on single verb and noun naming and lexical retrieval in sentences across a variety of tasks across participants. Generalization to connected speech was observed for 3 of 4 participants. CONCLUSIONS: Though preliminary, these results indicate that VNeST may be effective in promoting generalization from single word naming to connected speech in persons with moderate aphasia. A number of clinical implications related to treatment efficiency are discussed.