Language Production Abilities Research Articles

Is it up to language? Pragmatic competence in Croatian preschool children with autism and typical development

Objectives The relationship between structural language ability and pragmatics is not fully understood, in either individuals with autism or those with typical development (TD). Despite the well-established understanding that core deficits in autism lie in pragmatics, specific pragmatic behaviours that distinguish autistic children (AC) from their TD peers are not sufficiently described. The aims of this study were as follows: to investigate the differences in language abilities and pragmatic competence between AC and those with TD; to examine the relationship between language comprehension/production and pragmatic competence in both groups; and to identify the items of pragmatic composite that are most discriminative in detecting AC. Methods The participants in this study were preschool-aged children with TD (N = 45; mean age 65.5 months) and AC with average nonverbal IQ scores (N = 32; mean age 72.9 months). Language production and comprehension abilities were assessed using the New Reynell Developmental Language Scales (4th edition), and pragmatic competence was measured using the Children’s Communication Checklist (CCC). Results For all language and pragmatic variables, AC performed worse than those with TD. Pragmatic competencies did not correlate with structural language skills in either group, except for a correlation between language production and coherence in the TD. Finally, certain pragmatic behaviours common to many AC and rarely found in children with TD were identified as potential distinguishing features between the two groups. Conclusions This study underscores the importance of incorporating pragmatic assessments alongside traditional language evaluations and suggests that interventions should target pragmatic competence specifically, especially in preschool AC.

The Use of Digital English Textbooks: A Study on Comprehension and Language Production Abilities Among Young Learners

The shift from traditional to digital textbooks in education brings both prospects and hurdles, especially in teaching English to young learners. Despite the widespread adoption of digital textbooks, their impact on students' language skills and teacher-student interaction needs more exploration. This study aims to thoroughly evaluate how digital textbooks affect English comprehension and production among young learners and teachers. The research conducted at SDS Islam Ar-Risalah Jember involved two teachers and eleven students, employing a descriptive qualitative method. Observations, interviews, and document analysis were utilized to gather data, analyzed through the Miles and Huberman method, pinpointing trends in digital textbook usage and understanding. Results suggest digital English textbooks significantly improve young learners' and teachers' English skills, enhancing speaking, reading, writing, and listening abilities. These resources offer a dynamic and interactive educational experience. However, transitioning to digital tools introduces challenges like infrastructural limitations and the need for teaching method adjustments. Addressing these issues is essential for fully leveraging digital textbooks in education. In conclusion, while digital textbooks can boost English language mastery among young learners and teachers, realizing this potential requires overcoming certain technological and pedagogical obstacles.

The volume and the distribution of premorbid white matter hyperintensities: Impact on post-stroke aphasia.

White matter hyperintensities (WMH) are a radiological manifestation of progressive white matter integrity loss. The total volume and distribution of WMH within the corpus callosum have been associated with pathological cognitive ageing processes but have not been considered in relation to post-stroke aphasia outcomes. We investigated the contribution of both the total volume of WMH, and the extent of WMH lesion load in the corpus callosum to the recovery of language after first-ever stroke. Behavioural and neuroimaging data from individuals (N = 37) with a left-hemisphere stroke were included at the early subacute stage of recovery. Spoken language comprehension and production abilities were assessed using word and sentence-level tasks. Neuroimaging data was used to derive stroke lesion variables (volume and lesion load to language critical regions) and WMH variables (WMH volume and lesion load to three callosal segments). WMH volume did not predict variance in language measures, when considered together with stroke lesion and demographic variables. However, WMH lesion load in the forceps minor segment of the corpus callosum explained variance in early subacute comprehension abilities (t = -2.59, p = .01) together with corrected stroke lesion volume and socio-demographic variables. Premorbid WMH lesions in the forceps minor were negatively associated with early subacute language comprehension after aphasic stroke. This negative impact of callosal WMH on language is consistent with converging evidence from pathological ageing suggesting that callosal WMH disrupt the neural networks supporting a range of cognitive functions.

CompreTAP: Feasibility and reliability of a new language comprehension mapping task via preoperative navigated transcranial magnetic stimulation

ObjectiveStimulation-based language mapping approaches that are used pre- and intraoperatively employ predominantly overt language tasks requiring sufficient language production abilities. Yet, these production-based setups are often not feasible in brain tumor patients with severe expressive aphasia. This pilot study evaluated the feasibility and reliability of a newly developed language comprehension task with preoperative navigated transcranial magnetic stimulation (nTMS). MethodsFifteen healthy subjects and six brain tumor patients with severe expressive aphasia unable to perform classic overt naming tasks underwent preoperative nTMS language mapping based on an auditory single-word Comprehension TAsk for Perioperative mapping (CompreTAP). Comprehension was probed by button-press responses to auditory stimuli, hence not requiring overt language responses. Positive comprehension areas were identified when stimulation elicited an incorrect or delayed button press. Error categories, case-wise cortical error rate distribution and inter-rater reliability between two experienced specialists were examined. ResultsOverall, the new setup showed to be feasible. Comprehension-disruptions induced by nTMS manifested in no responses, delayed or hesitant responses, searching behavior or selection of wrong target items across all patients and controls and could be performed even in patients with severe expressive aphasia. The analysis agreement between both specialists was substantial for classifying comprehension-positive and -negative sites. Extensive left-hemispheric individual cortical comprehension sites were identified for all patients. Apart from one case presenting with transient worsening of aphasic symptoms, pre-existing language deficits did not aggravate if results were used for subsequent surgical planning. ConclusionEmploying this new comprehension-based nTMS setup allowed to identify language relevant cortical sites in all healthy subjects and severely aphasic patients who were thus far precluded from classic production-based mapping. This pilot study, moreover, provides first indications that the CompreTAP mapping results may support the preservation of residual language function if used for subsequent surgical planning.

Cerebral perfusion in post-stroke aphasia and its relationship to residual language abilities.

Stroke alters blood flow to the brain resulting in damaged tissue and cell death. Moreover, the disruption of cerebral blood flow (perfusion) can be observed in areas surrounding and distal to the lesion. These structurally preserved but suboptimally perfused regions may also affect recovery. Thus, to better understand aphasia recovery, the relationship between cerebral perfusion and language needs to be systematically examined. In the current study, we aimed to evaluate (i) how stroke affects perfusion outside of lesioned areas in chronic aphasia and (ii) how perfusion in specific cortical areas and perilesional tissue relates to language outcomes in aphasia. We analysed perfusion data from a large sample of participants with chronic aphasia due to left hemisphere stroke (n = 43) and age-matched healthy controls (n = 25). We used anatomically defined regions of interest that covered the frontal, parietal, and temporal areas of the perisylvian cortex in both hemispheres, areas typically known to support language, along with several control regions not implicated in language processing. For the aphasia group, we also looked at three regions of interest in the perilesional tissue. We compared perfusion levels between the two groups and investigated the relationship between perfusion levels and language subtest scores while controlling for demographic and lesion variables. First, we observed that perfusion levels outside the lesioned areas were significantly reduced in frontal and parietal regions in the left hemisphere in people with aphasia compared to the control group, while no differences were observed for the right hemisphere regions. Second, we found that perfusion in the left temporal lobe (and most strongly in the posterior part of both superior and middle temporal gyri) and inferior parietal areas (supramarginal gyrus) was significantly related to residual expressive and receptive language abilities. In contrast, perfusion in the frontal regions did not show such a relationship; no relationship with language was also observed for perfusion levels in control areas and all right hemisphere regions. Third, perilesional perfusion was only marginally related to language production abilities. Cumulatively, the current findings demonstrate that blood flow is reduced beyond the lesion site in chronic aphasia and that hypoperfused neural tissue in critical temporoparietal language areas has a negative impact on behavioural outcomes. These results, using perfusion imaging, underscore the critical and general role that left hemisphere posterior temporal regions play in various expressive and receptive language abilities. Overall, the study highlights the importance of exploring perfusion measures in stroke.

Resting State Network Segregation Modulates Age-Related Differences in Language Production.

Older adults typically exhibit decline in language production. However, how the brain supports or fails to support these processes is unclear. Moreover, there are competing hypotheses about the nature of age-related neural changes and whether age-related increases in neural activity reflect compensation or a decline in neural efficiency. In the current study, we investigated the neural bases of language production focusing on resting state functional connectivity. We hypothesized that language production performance, functional connectivity, and their relationship would differ as a function of age. Consistent with prior work, older age was associated with worse language production performance. Functional connectivity analyses showed that network segregation within the left hemisphere language network was maintained across adulthood. However, increased age was associated with lower whole brain network segregation. Moreover, network segregation was related to language production ability. In both network analyses, there were significant interactions with age-higher network segregation was associated with better language production abilities for younger and middle-aged adults, but not for older adults. Interestingly, there was a stronger relationship between language production and the whole brain network segregation than between production and the language network. These results highlight the utility of network segregation measures as an index of brain function, with higher network segregation associated with better language production ability. Moreover, these results are consistent with stability in the left hemisphere language network across adulthood and suggest that dedifferentiation among brain networks, outside of the language network, is a hallmark of aging and may contribute to age-related language production difficulties.

Early Subacute White Matter Hyperintensities and Recovery of Language After Stroke

Background White matter hyperintensities (WMH) are considered to contribute to diminished brain reserve, negatively impacting on stroke recovery. While WMH identified in the chronic phase after stroke have been associated with post-stroke aphasia, the contribution of premorbid WMH to the early recovery of language across production and comprehension has not been investigated. Objective To investigate the relationship between premorbid WMH severity and longitudinal comprehension and production outcomes in aphasia, after controlling for stroke lesion variables. Methods Longitudinal behavioral data from individuals with a left-hemisphere stroke were included at the early subacute (n = 37) and chronic (n = 28) stage. Spoken language comprehension and production abilities were assessed at both timepoints using word and sentence-level tasks. Magnetic resonance imaging (MRI) was performed at the early subacute stage to derive stroke lesion variables (volume and proportion damage to critical regions) and WMH severity rating. Results The presence of severe WMH explained an additional 18% and 25% variance in early subacute (t = −3.00, p = .004) and chronic (t = −3.60, P = .001) language comprehension abilities respectively, after controlling for stroke lesion variables. WMH did not predict additional variance of language production scores. Conclusions Subacute clinical MRI can be used to improve prognoses of recovery of aphasia after stroke. We demonstrate that severe early subacute WMH add to the prediction of impaired longitudinal language recovery in comprehension, but not production. This emphasizes the need to consider different domains of language when investigating novel neurobiological predictors of aphasia recovery.

Age differences in semantic network structure: Acquiring knowledge shapes semantic memory.

Computational research suggests that semantic memory, operationalized as semantic memory networks, undergoes age-related changes. Previous work suggests that concepts in older adults' semantic memory networks are more separated, more segregated, and less connected to each other. However, cognitive network research often relies on group averages (e.g., young vs. older adults), and it remains unclear if individual differences influence age-related disparities in language production abilities. Here, we analyze the properties of younger and older participants' individual-based semantic memory networks based on their semantic relatedness judgments. We related individual-based network measures-clustering coefficient (CC; connectivity), global efficiency, and modularity (structure)-to language production (verbal fluency) and vocabulary knowledge. Similar to previous findings, we found significant age effects: CC and global efficiency were lower, and modularity was higher, for older adults. Furthermore, vocabulary knowledge was significantly related to the semantic memory network measures: corresponding with the age effects, CC and global efficiency had a negative relationship, while modularity had a positive relationship with vocabulary knowledge. More generally, vocabulary knowledge significantly increased with age, which may reflect the critical role that the accumulation of knowledge within semantic memory has on its structure. These results highlight the impact of diverse life experiences on older adults' semantic memory and demonstrate the importance of accounting for individual differences in the aging mental lexicon. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

On the Relationship between Speech Intelligibility and Fluency Indicators among English-Speaking Individuals with Parkinson's Diseases.

The purpose of the study is to investigate how much of variance in Parkinson's Disease (PD) individuals' speech intelligibility could be predicted by seven speech fluency indicators (i.e., repetition, omission, distortion, correction, unfilled pauses, filled pauses, and speaking rate). Speech data were retrieved from a database containing a reading task produced by a group of 16 English-speaking individuals with PD (Jaeger, Trivedi & Stadtchnitzer, 2019). The results from a multiple regression indicated that an addition of 54% of variance in the speech intelligibility scores among individuals with PD could be accounted for after the speakers' PD severity level measured based on Hoehn and Yahr's (1967) disease stage was included as a covariate. In addition, omission and correction were the two fluency indicators that contributed to the general intelligibility score in a statistically significant way. Specifically, for every one-unit gain in the number of correction and omission, speech intelligibility scores would decline by 0.687 and 0.131 point (out of a 7-point scale), respectively. The current study hence supported Magee, Copland, and Vogel's (2019) view that the language production abilities and quantified dysarthria measures among individuals with PD should be explored together. Additionally, the clinical implications based on the current findings were discussed.

Longitudinal Changes in Cognition, Behaviours, and Functional Abilities in the Three Main Variants of Primary Progressive Aphasia: A Literature Review.

Primary progressive aphasias (PPAs) are a group of neurodegenerative diseases presenting with insidious and relentless language impairment. Three main PPA variants have been described: the non-fluent/agrammatic variant (nfvPPA), the semantic variant (svPPA), and the logopenic variant (lvPPA). At the time of diagnosis, patients and their families’ main question pertains to prognosis and evolution, but very few data exist to support clinicians’ claims. The objective of this study was to review the current literature on the longitudinal changes in cognition, behaviours, and functional abilities in the three main PPA variants. A comprehensive review was undertaken via a search on PUBMED and EMBASE. Two authors independently reviewed a total of 65 full-text records for eligibility. A total of 14 group studies and one meta-analysis were included. Among these, eight studies included all three PPA variants. Eight studies were prospective, and the follow-up duration was between one and five years. Overall, svPPA patients showed more behavioural disturbances both at baseline and over the course of the disease. Patients with lvPPA showed a worse cognitive decline, especially in episodic memory, and faster progression to dementia. Finally, patients with nfvPPA showed the most significant losses in language production and functional abilities. Data regarding the prodromal and last stages of PPA are still missing and studies with a longer follow-up observation period are needed.

Assessing abstract thought and its relation to language with a new nonverbal paradigm: Evidence from aphasia

In recent years, language has been shown to play a number of important cognitive roles over and above the communication of thoughts. One hypothesis gaining support is that language facilitates thought about abstract categories, such as democracy or prediction. To test this proposal, a novel set of semantic memory task trials, designed for assessing abstract thought non-linguistically, were normed for levels of abstractness. The trials were rated as more or less abstract to the degree that answering them required the participant to abstract away from both perceptual features and common setting associations corresponding to the target image. The normed materials were then used with a population of people with aphasia to assess the relationship of abstract thought to language. While the language-impaired group with aphasia showed lower overall accuracy and longer response times than controls in general, of special note is that their response times were significantly longer as a function of a trial's degree of abstractness. Further, the aphasia group's response times in reporting their degree of confidence (a separate, metacognitive measure) were negatively correlated with their language production abilities, with lower language scores predicting longer metacognitive response times. These results provide some support for the hypothesis that language is an important aid to abstract thought and to metacognition about abstract thought.

Determining Language Production Abilities in Indian Adolescents between 10 and 16 Years of Age: Using a Conversational based Task

ë°°ê²½ 및 ëª©ì  의사소통은 대화 상대자의 ì§€ì  상태에 영향을 받는 ì‚¬íšŒì  상호작용이다. 다양한 발화로 이루어진 대화가 언어산출 ëŠ¥ë ¥ì„ í‰ê°€í• ìˆ˜ 있는 가장 자연스러운 자료를 ì œê³µí• ìˆ˜ 있다. 이에 본 연구는 대화에 기반한 ê³¼ì œë¥¼ 사용하여 인도 ì²­ì†Œë „ì˜ 발화 발달 특성을 ì¸¡ì •í•˜ê³ ìž 하였다. 방법 10-16세의 총 90ëª ì˜ 참가자가 여섯 ì—°ë ¹ëŒ€ë¡œ 분류되었다. 본 연구는 자극개발 1단계, 실시 2단계, 분석 3단계 등 총 3단계로 구성되었다. 본 연구에서는 의사소통 ìœ ë‹›(CU), ì§„ìˆ (ST), 질문(QU), 포기된 발화(AU), 방해받은 발화(IU), 질문 대답(RQ), 예/아니오 응답(RYN), 억양에 대한 응답(RIP), 중첩된 발화(UOS) 등을 SALT 프로그램을 이용하여 분석하였다. ê²°ê³¼ 대부분의 ë°œí™”ìœ í˜•ì—ì„œ 변화가 관찰되었다. ì•„ë ¸ë°” ê²°ê³¼, CU, ST, QU, UOS, RQ에서 ìœ ì˜í•œ 차이가 관찰되었다(p<.05). 하지만 IU, AU, RYN, RIP에서는 ìœ ì˜í•œ 차이가 관찰되지 않았다(p>.05). 집단 간 차이를 살펴보기 위하여 본페로니 사후검증을 실시하였다. ë ¼ì˜ 및 ê²°ë¡ ë³¸ 연구 결과는 ì²­ì†Œë „ê¸°ì—ë„ ì–¸ì–´ì‚°ì¶œëŠ¥ë ¥ì´ ë°œì „í•œë‹¤ëŠ” ì ì„ 시사한다. 특히 일부 ë°œí™”ìœ í˜•ì€ ì²­ì†Œë „ì˜ ì–¸ì–´ëŠ¥ë ¥ì„ ì¸¡ì •í•˜ëŠ”ë° ìœ ìš©í• ê²ƒì´ë‹¤. Keywords: ì²­ì†Œë „, 대화, 언어, 산출

Effects of working memory intervention on language production by individuals with dementia

ABSTRACT The purpose of this study was to investigate the effects of working memory intervention on language production by people with mild or moderate Alzheimer’s disease (AD). A total of 39 AD patients, 21 with mild AD and 18 with moderate AD and 18 normal controls were given 18 sessions of working memory intervention. After these sessions, the transfer effects and maintenance effects at the 3-month follow-up were assessed. A word-span task and a digit-span task were used to evaluate working memory. Language-production abilities were compared through four tasks: a verbal fluency, a confrontation naming, a word definition, and a picture-description task. Task performances of working memory and language production were the lowest in the baseline stage and the highest in the transfer-effect stage. The three groups had transfer effects in all tasks, while the maintenance effects were limited by groups and tasks. This study proves that working memory intervention for AD patients is effective for language production. In addition, we have paved the way for working memory intervention to improve language production by AD patients in clinical settings by presenting the transfer and maintenance effect for each task of language production.

Exploring Perceptions of Novelty and Mirth in Elicited Figurative Language Production

ABSTRACT Most research of figurative language production examines naturalistic discourse. However, laboratory studies of elicited figurative language production are useful because they provide insight into whether specific individual differences are associated with differences in figurative language production ability. In this sense, elicited figurative language production studies mirror the approach many studies of figurative language processing and comprehension take. Accordingly, this study is an investigation into perceptions of novelty and mirth associated with figurative language production. Data in this study come from elicited figurative language production tasks for metaphorical comparisons and sarcastic replies, which were rated based on perceptions of novelty and mirth as well as conceptual distance (metaphors) and incongruity (sarcastic replies). Two individual differences, Need for Cognition and Thinking, along with other differences such as prompt type and production time were used to predict the novelty and mirth ratings. The results demonstrate a significant effect of Need for Cognition on metaphors but not for sarcastic replies, whereas no significant effects were observed for Thinking. Moreover, longer production times were associated with higher ratings for both metaphors and sarcastic replies. Finally, the results highlighted the manner in which prompt characteristics influenced participants’ responses, especially so for sarcastic replies.

White matter disconnection is related to age-related phonological deficits

Older adults have more language production difficulties than younger adults but display largely comparable language comprehension abilities. The Transmission Deficit Hypothesis suggests that production difficulties stem from an age-related increase in phonological signal transmission failures, while the semantic system, being more redundant than the phonological system, allows comprehension to be relatively preserved despite signal failures. Though the neural instantiation of the Transmission Deficit Hypothesis remains an open question, white matter represents one important factor to investigate. Metrics indicative of white matter connectivity across the brain, namely, Radial Diffusivity (RD) and Fractional Anisotropy (FA) have also been linked to age-related cognitive differences including naming difficulties. Using a Picture-Word Interference (PWI) task with 18 younger and 19 older healthy adults, we found that, across ages, better picture naming in the presence of phonological distractors was associated with lower RD across dorsal (r = −.35, p = .03), ventral (r = −.34, p = .04), and fronto-striatal (r = −.33, p = .04) tracts, and higher FA along dorsal tracts (r = .43, p = .008). The pattern of lower RD and higher FA, which is thought to reflect better white matter structure, points to the dorsal stream tracts as critical for performance on the PWI task. Moreover, the effects of RD and FA on performance were attenuated by the effect of age, reflecting the shared variance between age and white matter as it relates to language production ability.

Executive control in language production by children with and without language impairment.

Accumulating evidence suggests that the updating, inhibiting and shifting abilities underlying executive control are important for spoken language production in adults. However, little is known about this in children. To examine whether children with and without language impairment differ in all or only some of these executive abilities, and whether they show corresponding differences when these abilities are engaged in language production. Thirty-three children with specific language impairment (SLI) and 41 typically developing (TD) children (age matched, aged 8-12 years) completed standard executive control tests that measure the updating, inhibiting and shifting abilities. All children were native speakers of Dutch. Moreover, they performed a noun-phrase production task involving picture description within a picture-word interference paradigm. We measured their production accuracy and speed to assess length, distractor and switch effects, which reflect the updating, inhibiting and shifting abilities underlying executive control. Compared with TD children, the children with SLI had lower scores on all executive control tests. Moreover, they were overall slower and made more errors in the noun-phrase production task. Additionally, the magnitude of the distractor and switch effects was larger for the SLI than for the TD group. The results suggest that children with SLI have impaired language production and executive control abilities, and that some of the differences in the executive control abilities between SLI and TD groups were reflected in their language production.

Curvilinear Association Between Language Disfluency and FMR1 CGG Repeat Size Across the Normal, Intermediate, and Premutation Range.

Historically, investigations of FMR1 have focused almost exclusively on the clinical effects of CGG expansion within the categories of the premutation (55–200 CGG repeats) and fragile X syndrome (>200 CGG repeats). However, emerging evidence suggests that CGG-dependent phenotypes may occur across allele sizes traditionally considered within the “normal” range. This study adopted an individual-differences approach to determine the association between language production ability and CGG repeat length across the full range of normal, intermediate, and premutation alleles. Participants included 61 adult women with CGG repeats within the premutation (n = 37), intermediate (i.e., 41–54 repeats; n = 2), or normal (i.e., 6–40 repeats; n = 22) ranges. All participants were the biological mothers of a child with a developmental disorder, to control for the potential effects of parenting stress. Language samples were collected and the frequency of language disfluencies (i.e., interruptions in the flow of speech) served as an index of language production skills. Verbal inhibition skills, measured with the Hayling Sentence Completion Test, were also measured and examined as a correlate of language disfluency, consistent with theoretical work linking language disfluency with inhibitory deficits (i.e., the Inhibition Deficit Hypothesis). Blood samples were collected to determine FMR1 CGG repeat size. A general linear model tested CGG repeat size of the larger allele (allele-2) as the primary predictor of language disfluency, covarying for education level, IQ, age, and CGG repeats on the other allele. A robust curvilinear association between CGG length and language disfluency was detected, where low-normal (∼ <25 repeats) and mid-premutation alleles (∼90–110 repeats) were linked with higher rates of disfluency. Disfluency was not associated with inhibition deficits, which challenges prior theoretical work and suggests that a primary language deficit could account for elevated language disfluency in FMR1-associated conditions. Findings suggest CGG-dependent variation in language production ability, which was evident across individuals with and without CGG expansions on FMR1.

Language skills of children during the first 12 months after stuttering onset

PurposeTo describe the language development in a sample of young children who stutter during the first 12 months after stuttering onset was reported. MethodsLanguage production was analysed in a sample of 66 children who stuttered (aged 2–4 years). The sample were identified from a pre-existing prospective, community based longitudinal cohort. Data were collected at three time points within the first year after stuttering onset. Stuttering severity was measured, and global indicators of expressive language proficiency (length of utterances and grammatical complexity) were derived from the samples and summarised. Language production abilities of the children who stutter were contrasted with normative data. ResultsThe majority of children’s stuttering was rated as mild in severity, with more than 83% of participants demonstrating very mild or mild stuttering at each of the time points studied. The participants demonstrated developmentally appropriate spoken language skills comparable with available normative data. ConclusionIn the first year following the report of stuttering onset, the language skills of the children who were stuttering progressed in a manner that is consistent with developmental expectations.

Right hemisphere grey matter structure and language outcomes in chronic left hemisphere stroke.

The neural mechanisms underlying recovery of language after left hemisphere stroke remain elusive. Although older evidence suggested that right hemisphere language homologues compensate for damage in left hemisphere language areas, the current prevailing theory suggests that right hemisphere engagement is ineffective or even maladaptive. Using a novel combination of support vector regression-based lesion-symptom mapping and voxel-based morphometry, we aimed to determine whether local grey matter volume in the right hemisphere independently contributes to aphasia outcomes after chronic left hemisphere stroke. Thirty-two left hemisphere stroke survivors with aphasia underwent language assessment with the Western Aphasia Battery-Revised and tests of other cognitive domains. High-resolution T1-weighted images were obtained in aphasia patients and 30 demographically matched healthy controls. Support vector regression-based multivariate lesion-symptom mapping was used to identify critical language areas in the left hemisphere and then to quantify each stroke survivor's lesion burden in these areas. After controlling for these direct effects of the stroke on language, voxel-based morphometry was then used to determine whether local grey matter volumes in the right hemisphere explained additional variance in language outcomes. In brain areas in which grey matter volumes related to language outcomes, we then compared grey matter volumes in patients and healthy controls to assess post-stroke plasticity. Lesion-symptom mapping showed that specific left hemisphere regions related to different language abilities. After controlling for lesion burden in these areas, lesion size, and demographic factors, grey matter volumes in parts of the right temporoparietal cortex positively related to spontaneous speech, naming, and repetition scores. Examining whether domain general cognitive functions might explain these relationships, partial correlations demonstrated that grey matter volumes in these clusters related to verbal working memory capacity, but not other cognitive functions. Further, grey matter volumes in these areas were greater in stroke survivors than healthy control subjects. To confirm this result, 10 chronic left hemisphere stroke survivors with no history of aphasia were identified. Grey matter volumes in right temporoparietal clusters were greater in stroke survivors with aphasia compared to those without history of aphasia. These findings suggest that the grey matter structure of right hemisphere posterior dorsal stream language homologues independently contributes to language production abilities in chronic left hemisphere stroke, and that these areas may undergo hypertrophy after a stroke causing aphasia.

Language Development across the Life Span: A Neuropsychological/Neuroimaging Perspective.

Language development has been correlated with specific changes in brain development. The aim of this paper is to analyze the linguistic-brain associations that occur from birth through senescence. Findings from the neuropsychological and neuroimaging literature are reviewed, and the relationship of language changes observable in human development and the corresponding brain maturation processes across age groups are examined. Two major dimensions of language development are highlighted: naming (considered a major measure of lexical knowledge) and verbal fluency (regarded as a major measure of language production ability). Developmental changes in the brain lateralization of language are discussed, emphasizing that in early life there is an increase in functional brain asymmetry for language, but that this asymmetry changes over time, and that changes in the volume of gray and white matter are age-sensitive. The effects of certain specific variables, such as gender, level of education, and bilingualism are also analyzed. General conclusions are presented and directions for future research are suggested.