Four dimensions of naturalistic language production in aphasia after stroke.

There is a rich tradition of research on the neuroanatomical correlates of spoken language production in aphasia using constrained tasks (e.g., picture naming), which offer controlled insights into the distinct processes that govern speech and language (i.e., lexical-semantic access, morphosyntactic construction, phonological encoding, speech motor programming/execution). Yet these tasks do not necessarily reflect everyday language use. In contrast, naturalistic language production (also referred to as connected speech or discourse) more closely approximates typical processing demands, requiring the dynamic integration of all aspects of speech and language. The brain bases of naturalistic language production remain relatively unknown, however, in part because of the difficulty in deriving features that are salient, quantifiable, and interpretable relative to both speech-language processes and the extant literature. The present cross-sectional observational study seeks to address these challenges by leveraging a validated and comprehensive auditory-perceptual measurement system that yields four explanatory dimensions of performance-Paraphasia (misselection of words and sounds), Logopenia (paucity of words), Agrammatism (grammatical omissions), and Motor speech (impaired speech motor programming/execution). We used this system to characterize naturalistic language production in a large and representative sample of individuals with acute post-stroke aphasia (n = 118). Scores on each of the four dimensions were correlated with lesion metrics, and multivariate associations among the dimensions and brain regions were then explored. Our findings revealed distinct yet overlapping neuroanatomical correlates throughout the left-hemisphere language network. Paraphasia and Logopenia were associated primarily with posterior regions, spanning both dorsal and ventral streams, which are critical for lexical-semantic access and phonological encoding. In contrast, Agrammatism and Motor speech were associated primarily with anterior regions of the dorsal stream that are involved in morphosyntactic construction and speech motor planning/execution respectively. Collectively, we view these results as constituting a brain-behavior model of naturalistic language production in aphasia, aligning with both historical and contemporary accounts of the neurobiology of spoken language production.

The development of a novel, standardized, norm-referenced Arabic Discourse Assessment Tool (ADAT), including an examination of psychometric properties of discourse measures in aphasia.

BACKGROUND: People with aphasia (PWA) typically exhibit deficits in spoken discourse. Discourse analysis is the gold standard approach to assess language deficits beyond sentence level. However, the available discourse assessment tools are biased towards English and European languages and Western culture. Additionally, there is a lack of consensus on which discourse measures to use and limited evidence of the psychometric properties of published discourse measurements. AIMS: (1) To develop a standardized, norm-referenced, culturally and linguistically appropriate Arabic Discourse Assessment Tool (ADAT); and (2) to examine the psychometric properties of content and construct validity and interrater reliability of different discourse measures elicited using three discourse genres (descriptive, narrative and procedural) in neurotypical control adults and matched PWA. METHODS & PROCEDURES: Discourse samples were collected using three novel discourse stimuli that are sensitive to the Arabic language and culture from 70 neurotypical control adults and a matched group of 50 PWA. Transcription agreement was assessed. A standard approach was used to evaluate construct validity and interrater reliability for 16 discourse measures that assess fluency, language productivity, information content, lexical-semantics, lexical diversity, grammatical category, grammatical structure and syntactic complexity. Strong measures were identified based on their psychometric properties, and normative data were established on these measures. Discourse performance of PWA was then examined using the newly developed tool (ADAT). OUTCOMES & RESULTS: Transcription agreement was extremely high for all discourse stimuli in both groups. Eight discourse measures were proven to have consistently very high construct validity and consistently very good to excellent reliability across the three stimuli in both neurotypical control and aphasia groups: lexical information units, content information units, words per minute, discourse duration, number of different words, number of complete sentences and proportion of open and closed class words. Norms were established on these measures, and cut-off scores of impairments were determined. Other measures showed low construct validity and variable or poor reliability across the two groups. CONCLUSIONS & IMPLICATIONS: The newly developed, standardized, and norm-referenced tool (ADAT) consist of three discourse stimuli and eight high-quality discourse measures that assess multiple aspects of spoken discourse and were able to differentiate PWA from neurotypical adults consistently. ADAT also includes normative data and cut-off impairment scores. The tool has great potential to enhance clinical practice and research with Arabic speakers. Evidence was provided that not all discourse measures are of high quality, as some are vulnerable to differences between raters, discourse stimuli and groups. Clinicians and researchers can use ADAT for accurate aphasia assessments, better management plans and to monitor therapy effectiveness. ADAT can be further validated in other clinical populations with language impairments. WHAT THIS PAPER ADDS: What is already known on the subject Discourse analysis is the gold standard approach to assess language deficits beyond sentence level. However, existing discourse assessment tools are biased towards English and European languages and Western culture. Additionally, there is a lack of consensus on which discourse measures to use in aphasia, and limited evidence of the psychometric properties of published discourse measurements. What this paper adds to existing knowledge A novel, standardized, norm-referenced Arabic Discourse Assessment Tool (ADAT) was developed and validated in this study. ADAT was further validated among PWA. The study provides evidence that not all discourse measures are of high quality and thus should not be used with confidence. Specific measures are vulnerable to the type of stimuli, the rater and/or the tested group. On the other hand, eight discourse measures were identified to be reliable between different raters and across different stimuli for the two groups, and they were able to differentiate the discourse performance of PWA from neurotypical control adults. Normative data derived from neurotypical control adults were established on these strong measures, and the performance of PWA was classified as impaired based on these norms. What are the potential or actual clinical implications of this work? The present study provides a novel, standardized, norm-referenced, validated discourse assessment tool that is culturally and linguistically appropriate for use by Arabic speakers (ADAT). ADAT holds immense potential to enhance clinical practice and research with Arabic speakers. The study also identified strong discourse measures that can be used to assess language productivity, information content, lexical-semantics, lexical diversity, grammatical category, and syntactic complexity for accurate and comprehensive assessments. This will lead to better rehabilitation management by guiding the development of tailored client-centred interventions. ADAT can be utilized in clinical and research settings in PWA and has the potential to be further validated with other clinical populations.

The effects of watching subtitled videos on the perception of L2 connected speech by L1 Chinese-L2 English speakers.

The current study explores whether watching subtitled videos could facilitate L1 Chinese-L2 English speakers' perception of L2 English connected speech. Three hundred ninty seven Chinese college students of L2 English completed a video-based spot dictation task after watching English videos with or without L1/L2 subtitles, featuring various connected speech types (e.g., linking, deletion, and their combinations). Results suggested an overall facilitation effect of watching videos on L2 connected speech perception, which was modulated by proficiency, subtitle form, and the complexity of connected speech. First, subtitled videos were more facilitative than non-subtitled videos in L2 perception. Second, participants with higher L2 proficiency better perceived English connected speech than those with lower proficiency. Third, the more connective devices an item used, the more difficult it was for L2 perception. When this complexity was controlled, the L2 perception was not influenced by connected speech type. Finally, the complexity of connected speech also mediated the subtitle facilitation effects. When the connected speech involved triple connective devices, L2 speakers benefited more from L1 subtitles than L2 subtitles. The findings can provide insights into multi-modal speech perception and English connected speech learning.

The development of English language connected speech perception skills: an empirical study on Chinese EFL children.

Connected speech processes (CSPs) occur randomly in everyday conversations of native speakers; however, such phonological variations can bring about challenges for non-native listeners. Looking at CSP literature, there seems to be very few studies that involved young foreign language learners. Therefore, the present study aimed to explore the development of connected speech perception skills by focusing on 201 9- to 12-year-old Chinese EFL children. It also incorporated systematic error analysis to further probe into the specific perceptual difficulties. The results indicate that: (1) Despite a significantly ascending trend for the overall growth of perception skills, no significant differences were found between 11 and 12 year olds in elision and contraction, which suggests that the developmental trend varied depending on different CSP types; (2) Although random errors decreased with age, the number of lexicon and syntax errors gradually increased, and the distribution of perceptual errors shifted from the level of words and syllables to that of phonemes; (3) The primary types of errors resulting in the perception difficulties for elision and contraction were consonant errors, grammatical errors and morphology errors. Ergo, this study enhances the understanding of connected speech perception among EFL children and provides some implications for EFL/ESL listening instructions.

Clinician and Patient Perception of a Voice Therapy Program Utilizing a Variably Occluded Face Mask: A Pilot Study.

OBJECTIVE: The purpose of this investigation was to assess clinician and patient feedback about voice therapy using a variably occluded face mask (VOFM) and to determine if voice therapy augmented via a VOFM would result in favorable changes in patient self-perceived handicap, as well as acoustic and aerodynamic measures. METHODS/DESIGN: This pilot study used a prospective, pre-post single group design. Eleven patients with dysphonia due to primary muscle tension dysphonia (8) or benign vocal fold lesions (3) were recruited. Data collected included patient and clinician feedback of voice therapy using a VOFM, voice handicap index (VHI)-10, acoustic and aerodynamic measures. Data were collected before treatment (baseline) and 1-week post-therapy. Wilcoxon signed-rank tests were used to compare data pre- and post-therapy. RESULTS: Statistically significant improvement was observed for the VHI-10 with a median delta of -7. Clinician feedback generally reported that patients liked the VOFM, using the VOFM within the first two sessions of therapy, and within less than 10 min of use. All clinicians ranked the conversation level of the hierarchy as the most effective level. Three themes emerged from the Therapy Feedback Form: the VOFM was a (1) "Facilitator for Sensation," (2) a "Physical Tool," and that there was (3) "No Program Needed" to use the VOFM in voice therapy. There was a statistically significant improvement in cepstral peak prominence (p = 0.0329) and cepstral spectral index of dysphonia (p = 0.0164) in sustained vowels. DISCUSSION: This pilot study represents the first investigation into clinician and patient perceptions of using a VOFM. Reported measures via patient perception, as well as clinician perceptions, and some acoustic and aerodynamic measures showed that participants got better with VOFM voice therapy. Last, in general, both clinicians and patients liked utilizing a VOFM in voice therapy.

Silent Pauses and Speech Indices as Biomarkers for Primary Progressive Aphasia.

Background and Objectives: Recent studies highlight the importance of investigating biomarkers for diagnosing and classifying patients with primary progressive aphasia (PPA). Even though there is ongoing research on pathophysiological indices in this field, the use of behavioral variables, and especially speech-derived factors, has drawn little attention in the relevant literature. The present study aims to investigate the possible utility of speech-derived indices, particularly silent pauses, as biomarkers for primary progressive aphasia (PPA). Materials and Methods: We recruited 22 PPA patients and 17 healthy controls, from whom we obtained speech samples based on two elicitation tasks, i.e., cookie theft picture description (CTP) and the patients' personal narration of the disease onset and course. Results: Four main indices were derived from these speech samples: speech rate, articulation rate, pause frequency, and pause duration. In order to investigate whether these indices could be used to discriminate between the four groups of participants (healthy individuals and the three patient subgroups corresponding to the three variants of PPA), we conducted three sets of analyses: a series of ANOVAs, two principal component analyses (PCAs), and two hierarchical cluster analyses (HCAs). The ANOVAs revealed significant differences between the four subgroups for all four variables, with the CTP results being more robust. The subsequent PCAs and HCAs were in accordance with the initial statistical comparisons, revealing that the speech-derived indices for CTP provided a clearer classification and were especially useful for distinguishing the non-fluent variant from healthy participants as well as from the two other PPA taxonomic categories. Conclusions: In sum, we argue that speech-derived indices, and especially silent pauses, could be used as complementary biomarkers to efficiently discriminate between PPA and healthy speakers, as well as between the three variants of the disease.

A unified model of post-stroke language deficits including discourse production and their neural correlates.

The clinical profiles of individuals with post-stroke aphasia demonstrate considerable variation in the presentation of symptoms. Recent aphasiological studies have attempted to account for this individual variability using a multivariate data-driven approach (principal component analysis) on an extensive neuropsychological and aphasiological battery, to identify fundamental domains of post-stroke aphasia. These domains mainly reflect phonology, semantics and fluency; however, these studies did not account for variability in response to different forms of connected speech, i.e. discourse genres. In the current study, we initially examined differences in the quantity, diversity and informativeness between three different discourse genres, including a simple descriptive genre and two naturalistic forms of connected speech (storytelling narrative, and procedural discourse). Subsequently, we provided the first quantitative investigation on the multidimensionality of connected speech production at both behavioural and neural levels. Connected speech samples across descriptive, narrative, and procedural discourse genres were collected from 46 patients with chronic post-stroke aphasia and 20 neurotypical adults. Content analyses conducted on all connected speech samples indicated that performance differed across discourse genres and between groups. Specifically, storytelling narratives provided higher quantities of content words and lexical diversity compared to composite picture description and procedural discourse. The analyses further revealed that, relative to neurotypical adults, patients with aphasia, both fluent and non-fluent, showed reduction in the quantity of verbal production, lexical diversity, and informativeness across all discourses. Given the differences across the discourses, we submitted the connected speech metrics to principal component analysis alongside an extensive neuropsychological/aphasiological battery that assesses a wide range of language and cognitive skills. In contrast to previous research, three unique orthogonal connected speech components were extracted in a unified model, reflecting verbal quantity, verbal quality, and motor speech, alongside four core language and cognitive components: phonological production, semantic processing, phonological recognition, and executive functions. Voxel-wise lesion-symptom mapping using these components provided evidence on the involvement of widespread cortical regions and their white matter connections. Specifically, left frontal regions and their underlying white matter tracts corresponding to the frontal aslant tract and the anterior segment of the arcuate fasciculus were particularly engaged with the quantity and quality of fluent connected speech production while controlling for other co-factors. The neural correlates associated with the other language domains align with existing models on the ventral and dorsal pathways for language processing.

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.

Connected speech in progressive supranuclear palsy: a possible role in differential diagnosis.

BACKGROUND: Progressive supranuclear palsy (PSP) is an atypical Parkinsonism characterized by motor and neuropsycological disorders. Language could be impaired in PSP patients, also in Richardson variant (PSP-RS). The analysis of connected speech is used in neurodegenerative disorder to investigate different levels of language organization, including phonetic, phonological, lexico-semantic, morpho-syntactic, and pragmatic processing. OBJECTIVE: In our study, we aimed to investigate the language profile, especially connected speech, in early-stage PSP-RS and Parkinson's disease (PD) patients without predominant speech or language disorders. METHODS: Language was assessed using the Screening for Aphasia in NeuroDegeneration (SAND); connected speech analysis was conducted from the picture description subtest. RESULTS: We enrolled 48 patients, 22 PD and 26 PSP (18 PSP-RS and 8 non-RS). PSP-RS patients presented an impairment in language domain, particularly regarding connected speech. PSP-RS patients presented worse performances than PD in different scores. The output of PSP-RS patients was characterized by a reduction in number of sentences and subordinates with respect to PD; PSP presented also more repaired sequences and phonological and lexico-semantic errors than PD. Number of sentences and number of subordinates of the picture description task were identified as predictors of PSP diagnosis. CONCLUSION: In summary, the SAND scale is able to identify language impairment in PSP patients. The analysis of connected speech could highlight some important aspects of language impairment in PSP-RS patients, and it could be helpful in the differential diagnosis with PD.

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.

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.

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.

Neocortical activity tracks the hierarchical linguistic structures of self-produced speech during reading aloud.

How the human brain uses self-generated auditory information during speech production is rather unsettled. Current theories of language production consider a feedback monitoring system that monitors the auditory consequences of speech output and an internal monitoring system, which makes predictions about the auditory consequences of speech before its production. To gain novel insights into underlying neural processes, we investigated the coupling between neuromagnetic activity and the temporal envelope of the heard speech sounds (i.e., cortical tracking of speech) in a group of adults who 1) read a text aloud, 2) listened to a recording of their own speech (i.e., playback), and 3) listened to another speech recording. Reading aloud was here used as a particular form of speech production that shares various processes with natural speech. During reading aloud, the reader's brain tracked the slow temporal fluctuations of the speech output. Specifically, auditory cortices tracked phrases (<1 â€‹Hz) but to a lesser extent than during the two speech listening conditions. Also, the tracking of words (2-4 â€‹Hz) and syllables (4-8 â€‹Hz) occurred at parietal opercula during reading aloud and at auditory cortices during listening. Directionality analyses were then used to get insights into the monitoring systems involved in the processing of self-generated auditory information. Analyses revealed that the cortical tracking of speech at <1 â€‹Hz, 2-4 â€‹Hz and 4-8 â€‹Hz is dominated by speech-to-brain directional coupling during both reading aloud and listening, i.e., the cortical tracking of speech during reading aloud mainly entails auditory feedback processing. Nevertheless, brain-to-speech directional coupling at 4-8 â€‹Hz was enhanced during reading aloud compared with listening, likely reflecting the establishment of predictions about the auditory consequences of speech before production. These data bring novel insights into how auditory verbal information is tracked by the human brain during perception and self-generation of connected speech.

An Exploration of the Impact of Group Treatment for Aphasia on Connected Speech.

OBJECTIVE: Group treatment enables people with aphasia to practise communication skills outside the typical clinician-patient dyad. While there is evidence that this treatment format can improve participation in everyday communication, there is little evidence it impacts linguistic abilities. This project aimed to investigate the effects of 'typical' group treatment on the communication skills of people with aphasia with a focus on word retrieval in discourse. METHODS: Three people with aphasia took part in a 6-week group therapy programme. Each week focused on a different topic, and three topics also received a home programme targeting word retrieval. The six treated topics were compared with two control topics, with regard to language production in connected speech. Semistructured interviews were collected twice prior to treatment and twice following the treatment and analysed using (a) word counts; (b) the profile of word errors and retrieval in speech; (c) a measure of propositional idea density, and (d) perceptual discourse ratings. RESULTS: Two participants showed no significant improvements; one participant showed significant improvement on discourse ratings. CONCLUSIONS: This study provides limited support for group treatment, leading to improved communication as measured by semistructured interviews, even when supplemented with a home programme. We suggest that either group treatment, as implemented here, was not an effective approach for improving communication for our participants and/or that outcome measurement was limited by difficulty assessing changes in connected speech.

Protocol for the Connected Speech Transcription of Children with Speech Disorders: An Example from Childhood Apraxia of Speech.

OBJECTIVE: While it is known that connected speech has different features to single-word speech, there are currently few recommendations regarding connected speech transcription. This research therefore aimed to develop a clinically feasible protocol for connected speech transcription. The protocol was then used to assist with description of the connected speech of children with childhood apraxia of speech (CAS), as little is known about their connected speech characteristics. PARTICIPANTS AND METHODS: Following a literature review, the Connected Speech Transcription Protocol (CoST-P) was iteratively developed and trialled. The CoST-P was then used to transcribe 50 connected utterances produced by 12 children (aged 6-13 years) with CAS. The characteristics of participants' connected speech were analysed to capture independent and relational analyses. RESULTS: The CoST-P was developed, trialled, and determined to have adequate reliability and fidelity. The frequency of inter-word segregation (mean = 29) was higher than intra-word segregation (mean = 4). Juncture accuracy was correlated with intelligibility metrics such as percentage of consonants correct. CONCLUSION: Connected speech transcription is challenging. The CoST-P may be a useful resource for speech-language pathologists and clinical researchers. Use of the CoST-P assisted in displaying CAS speech characteristics unique to connected speech (e.g., inter-word segregation and juncture).

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.

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.

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.

Perception of Native English Reduced Forms in Adverse Environments by Chinese Undergraduate Students.

Previous research has shown that learners of English-as-a-second-language (ESL) have difficulties in understanding connected speech spoken by native English speakers. Extending from past research limited to quiet listening condition, this study examined the perception of English connected speech presented under five adverse conditions, namely multi-talker babble noise, speech-shaped noise, factory noise, whispering and sad emotional tones. We tested a total of 64 Chinese ESL undergraduate students, using a battery of listening tasks. Results confirmed that the recognition of English native speech was more challenging for Chinese ESL learners under unfavorable listening conditions, in comparison to a noise-free listening condition. These findings carry significant implications for the importance of training and assessments on connected speech perception across various listening environments.

Connected speech as a marker of disease progression in autopsy-proven Alzheimer's disease.

Although an insidious history of episodic memory difficulty is a typical presenting symptom of Alzheimer's disease, detailed neuropsychological profiling frequently demonstrates deficits in other cognitive domains, including language. Previous studies from our group have shown that language changes may be reflected in connected speech production in the earliest stages of typical Alzheimer's disease. The aim of the present study was to identify features of connected speech that could be used to examine longitudinal profiles of impairment in Alzheimer's disease. Samples of connected speech were obtained from 15 former participants in a longitudinal cohort study of ageing and dementia, in whom Alzheimer's disease was diagnosed during life and confirmed at post-mortem. All patients met clinical and neuropsychological criteria for mild cognitive impairment between 6 and 18 months before converting to a status of probable Alzheimer's disease. In a subset of these patients neuropsychological data were available, both at the point of conversion to Alzheimer's disease, and after disease severity had progressed from the mild to moderate stage. Connected speech samples from these patients were examined at later disease stages. Spoken language samples were obtained using the Cookie Theft picture description task. Samples were analysed using measures of syntactic complexity, lexical content, speech production, fluency and semantic content. Individual case analysis revealed that subtle changes in language were evident during the prodromal stages of Alzheimer's disease, with two-thirds of patients with mild cognitive impairment showing significant but heterogeneous changes in connected speech. However, impairments at the mild cognitive impairment stage did not necessarily entail deficits at mild or moderate stages of disease, suggesting non-language influences on some aspects of performance. Subsequent examination of these measures revealed significant linear trends over the three stages of disease in syntactic complexity, semantic and lexical content. The findings suggest, first, that there is a progressive disruption in language integrity, detectable from the prodromal stage in a subset of patients with Alzheimer's disease, and secondly that measures of semantic and lexical content and syntactic complexity best capture the global progression of linguistic impairment through the successive clinical stages of disease. The identification of disease-specific language impairment in prodromal Alzheimer's disease could enhance clinicians' ability to distinguish probable Alzheimer's disease from changes attributable to ageing, while longitudinal assessment could provide a simple approach to disease monitoring in therapeutic trials.