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Multilingualism in semantic dementia: language-dependent lexical retrieval from degraded conceptual representations
Abstract and Figures
Background: Patients with the semantic variant of Primary Progressive Aphasia (svPPA) offer a unique opportunity to study the relationship between lexical retrieval and semantics, as they are characterised by progressive degradation of central semantic representations. However, there are few studies of how lexical retrieval across languages is affected in multilingual speakers.
Aims: We examine the impact of conceptual degradation in a trilingual patient (TC) with svPPA, to investigate whether the semantic memory breakdown affects her three languages similarly (English-Catalan-Spanish) in different linguistic tasks.
Methods & Procedures: We followed up her performance over one year in several tasks including: (a) naming with or without semantic interference contexts, (b) word translation, (c) word- and sentence-picture matching, (d) associative semantic priming and (e) language switching.
Outcomes & Results: There was significant response consistency between languages in the items that were relatively well-known and more semantically degraded, at least in a standard picture naming task. The patient’s sentence-to-picture matching did not show progressive deterioration in any language. However, some aspects of lexical retrieval showed language-dependency, as indexed by different patterns of performance in semantically-blocked cyclical naming task across languages.
Conclusions: These data suggest that while degradation of central semantic representations affects all languages, this deficit can be amplified or ameliorated by the strength of conceptual to lexical mappings, which varies across languages.
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... [43] described that the Rowland Universal Dementia Assessment Scale is specifically designed to assess cognitive impairment in culturally and linguistically diverse populations with an established cut-off to indicate cognitive impairment. Calabria [62] and Tee [63] described that normative data were available for the tasks/tests utilized in each of their respective studies. ...
... Two studies reported testing bilingual speakers in one language [44,62]. In Calabria et al. [62], although the participant was assessed in one language (Spanish), instructions were provided in the participant's other language (Catalan) due to the participant's preference for that language and the authors indicated that Spanish instruction was used for those tests available in Spanish. ...
... Two studies reported testing bilingual speakers in one language [44,62]. In Calabria et al. [62], although the participant was assessed in one language (Spanish), instructions were provided in the participant's other language (Catalan) due to the participant's preference for that language and the authors indicated that Spanish instruction was used for those tests available in Spanish. In de Leon et al. [44], historical data were utilized wherein participants were tested in English if they had adequate proficiency and did not require an interpreter/ translator. ...
Background:
Primary progressive aphasia (PPA) is a neurodegenerative syndrome characterized by speech and/or language impairment with relatively spared cognition. Research investigating behavioral speech-language intervention and methods for cognitive-linguistic assessment in PPA has predominantly centered around monolingual speakers. This gap hinders the widespread adoption of evidence-based approaches and exacerbates the inequities faced by culturally and linguistically diverse populations living with PPA.
Objective:
This scoping review synthesizes the current evidence for assessment and treatment practices in bilingual PPA as well as the operationalization of bilingualism in PPA.
Methods:
Arksey & O'Malley's scoping review methodology was utilized. Information was extracted from each study and entered into a data-charting template designed to capture information regarding operationalization of bilingualism in PPA and assessment and treatment practices.
Results:
Of the 16 identified studies, 14 reported the results of assessments conducted in both languages. Three studies reported positive naming treatment outcomes. Thirteen studies included English-speaking participants, revealing linguistic bias. Most studies reported age of acquisition, proficiency, and patterns of language use rather than providing an operational definition for bilingualism.
Conclusions:
Neither formal assessment measures nor clear guidelines for assessment of bilingual PPA currently exist; however, language-specific measures are emerging. Speech-language intervention in bilingual PPA has been relatively unexplored, representing a significant gap in the literature. In order to improve diagnostic and treatment options for bilingual PPA, targeted efforts to increase representation of bilinguals from various sociocultural contexts, as well as those who speak a variety of language pairs, is necessary.
... Post-stroke aphasia patients with semantic control deficits have more widespread lesions over parietal and frontal areas (Ralph et al., 2017), whereas semantic dementia primarily affects the anterior temporal lobe and, to a lesser extent, the angular gyrus, primarily in the left hemisphere (Hodges & Patterson, 2007). All rights reserved To see whether access and storage deficits affect lexical retrieval, we can compare the results of two studies in which semantic cyclic naming in patients' two languages (Calabria et al., 2019b(Calabria et al., , 2021a. The patient with semantic dementia presented a typical atrophy over the left anterior temporal lobe (see Figure 6A), whereas patients with post-stroke aphasia had brain lesions over the territory of the left medial cerebral artery. ...
... B. Figure 6. (A) Cerebral atrophy of the bilingual patient with semantic dementia (Calabria et al., 2021a); (B) Semantic interference effect in bilingual patients with post-stroke aphasia (Calabria et al., 2019b) and a bilingual patient with semantic dementia (Calabria et al., 2021b) in the semantic cyclic naming task in bilinguals could be differentiated. During recent years, the small number of studies centered upon bilingual patients with PPA has increased (Calabria et al., 2021b;Costa et al., 2019;Druks & Weekes, 2013;Ellajosyula et al., 2020;Filley et al., 2006;Hernández et al., 2008;Karpathiou et al., 2018;Simões et al., 2009;Zanini et al., 2011), but neuropsychology and psycholinguistics should continue to work together to advance in this promising field of research in the future. ...
The field of neuropsychology can contribute to bilingualism research from a multidisciplinary perspective that ranges from psycholinguistics and brain imaging studies. While the psycholinguistic approach provides the outlook on linguistic processes in experimental study of patients with brain damage, neural models define the underlying brain areas of such processes and help to predict language deficits in said patients. Current neural models of bilingualism do not provide accurate predictions of deficits in bilinguals with brain damage since they have not been tested in a systematic way. However, they do offer a roadmap for the underlying cognitive and linguistic processes of bilingual language control and speech production. In this chapter, I propose how a neurolinguistic approach to bilingualism might be implemented in neuropsychology by including: (a) the application of traditional methods of cognitive (neuro)psychology to the field of bilingualism, such as dissociations, (b) the use of psycholinguistic methods, and (c) how neurodegenerative diseases may be a neuropsychological paradigm in which one can study bilingual language processes.
... Furthermore, language switching tasks have been useful in assessing the integrity of BLC mechanisms. Calabria et al. [23] found that, in semantic dementia, switching abilities measured via language switching tasks may be spared despite a marked degradation of semantic memory and anomic deficits. Finally, a series of studies in patients with neurodegeneration in the basal ganglia have highlighted an increased impact on BLC deficits compared to other control mechanisms; results indicated that language switching abilities can be more affected than non-linguistic control abilities in bilingual patients with Parkinson's disease (PD) [20] and that language switching is clearly dissociated from other language control abilities [21]. ...
... Interestingly, although Pt 3 committed a large number of omission errors across trials (see Table 5), she did so without any clear deficit in language task engagement or disengagement, as she was able to manage cross-language interference and perform switches during the dual-language condition. These results clearly suggest that word production deficits in bilinguals are to some extent dissociated from the deficits in controlling the two languages [23], as the neural models of bilingualism would also suggest. Although these two systems overlap in a number of brain areas [2,5,66], some are specific to language control and the absence of language control deficits in BWAs could indicate that said areas are spared from brain damage. ...
As studies of bilingual language control (BLC) seek to explore the underpinnings of bilinguals' abilities to juggle two languages, different types of language switching tasks have been used to uncover switching and mixing effects and thereby reveal what proactive and reactive control mechanisms are involved in language switching. Voluntary language switching tasks, where a bilingual participant can switch freely between their languages while naming, are being utilized more often due to their greater ecological validity compared to cued switching paradigms. Because this type of task had not yet been applied to language switching in bilingual patients, our study sought to explore voluntary switching in bilinguals with aphasia (BWAs) as well as in healthy bilinguals. In Experiment 1, we replicated previously reported results of switch costs and mixing benefits within our own bilingual population of Catalan-Spanish bilinguals. With Experiment 2, we compared both the performances of BWAs as a group and as individuals against control group performance. Results illustrated a complex picture of language control abilities, indicating varying degrees of association and dissociation between factors of BLC. Given the diversity of impairments in BWAs' language control mechanisms, we highlight the need to examine BLC at the individual level and through the lens of theoretical cognitive control frameworks in order to further parse out how bilinguals regulate their language switching.
... Bilinguals with aphasia (BWA) may encounter challenges in meeting these control demands if they have impairments in control abilities. Several studies have demonstrated reduced performance on language control tasks (e.g., Dash & Kar, 2014;Gray, 2020;Gray & Kiran, 2016; see Mooijman et al., 2022, for a review), but studies focusing on cued language switching abilities of BWA yielded mixed results (Calabria et al., 2019(Calabria et al., , 2021(Calabria et al., , 2014. When language switching by bilinguals with aphasia is investigated with verbal fluency tasks, it appears that BWA perform worse than neurologically healthy control participants when executive control demands are higher (Carpenter et al., 2021(Carpenter et al., , 2020Patra et al., 2020). ...
... Given the heightened weight on linguistic, verbal deficits in predominantly left cases, it is pivotal to further compare different native languages in cases of multilingual patients. For instance, recent evidence suggests that the central semantic representation loss equally affects all languages, yet the deficit is worsened or mitigated by language-specific aspects such as the strength of the lexical mapping (Calabria et al., 2021). Cases with predominantly right ATL atrophy manifest with prominent socioemotional, nonverbal semantic, and person-specific knowledge impairments (Edwards-Lee et al., 1997;Perry et al., 2001;Rosen et al., 2002;Rankin et al., 2006). ...
Frontotemporal dementia (FTD) is an umbrella term covering a plethora of progressive changes in executive functions, motor abilities, behavior, and/or language. Different clinical syndromes have been described in relation to localized atrophy, informing on the functional networks that underlie these specific cognitive, emotional, and behavioral processes. These functional declines are linked with the underlying neurodegeneration of frontal and/or temporal lobes due to diverse molecular pathologies. Initially, the accumulation of misfolded proteins targets specifically susceptible cell assemblies, leading to relatively focal neurodegeneration that later spreads throughout large-scale cortical networks. Here, we discuss the most recent clinical, neuropathological, imaging, and genetics findings in FTD-spectrum syndromes affecting the temporal lobe. We focus on the semantic variant of primary progressive aphasia and its mirror image, the right temporal variant of FTD. Incipient focal atrophy of the left anterior temporal lobe (ATL) manifests with predominant naming, word comprehension, reading, and object semantic deficits, while cases of predominantly right ATL atrophy present with impairments of socioemotional, nonverbal semantic, and person-specific knowledge. Overall, the observations in FTD allow for crucial clinical-anatomic inferences, shedding light on the role of the temporal lobes in both cognition and complex behaviors. The concerted activity of both ATLs is critical to ensure that percepts are translated into concepts, yet important hemispheric differences should be acknowledged. On one hand, the left ATL attributes meaning to linguistic, external stimuli, thus supporting goal-oriented, action-related behaviors (e.g., integrating sounds and letters into words). On the other hand, the right ATL assigns meaning to emotional, visceral stimuli, thus guiding socially relevant behaviors (e.g., integrating body sensations into feelings of familiarity).
Professor Albert Costa (1972-2018) was one of the most influential scholars in the fields of psycholinguistics and bilingualism. This book provides a faithful look at the most relevant lines of research in which he worked during his academic career. Written by some of his close collaborators and friends, the book presents a coherent summary of the most relevant psycholinguistic theories on language processing and bilingualism, including critical reviews to current models of lexical access, the representation of cognate words, neurolinguistic models of bilingualism, cross-linguistic effects in bimodal bilinguals (sign language), prediction processes and linguistic alignment in bilinguals, the influence of foreign-language effects in social cognition and the effects of bilingualism in emotion and decision making processing. This volume is a tribute to Prof. Costa and his work, and is born from a deep love and respect for his way of approaching the science of multilingualism from a psycholinguistic perspective.
Individuals with aphasia frequently show lexical retrieval deficits due to increased interference of semantically related competitors, a phenomenon that can be observed in tasks such as naming pictures grouped by semantic category. These deficits are explained in terms of impaired semantic control, a set of abilities that are to some extent dependent upon executive control (EC). However, the extent to which semantic control abilities can be affected in a second and non-dominant language has not been extensively explored. Additionally, findings in healthy individuals are inconclusive regarding the degree to which semantic processing is shared between languages. In this study, we explored the effect of brain damage on semantic processing by comparing the performance of bilingual individuals with aphasia on tasks involving semantic control during word production and comprehension. Furthermore, we explored whether semantic deficits are related to domain-general EC deficits. First, we investigated the naming performance of Catalan–Spanish bilinguals with fluent aphasia and age-matched healthy controls on a semantically blocked cyclic naming task in each of their two languages (Catalan and Spanish). This task measured semantic interference in terms of the difference in naming latencies between pictures grouped by the same semantic category or different categories. Second, we explored whether lexical deficits extend to comprehension by testing participants in a word-picture matching task during a mixed language condition. Third, we used a conflict monitoring task to explore the presence of EC deficits in patients with aphasia. We found two main results. First, in both language tasks, bilingual patients’ performances were more affected than those of healthy controls when they performed the task in their non-dominant language. Second, there was a significant correlation between the speed of processing on the EC task and the magnitude of the semantic interference effect exclusively in the non-dominant language. Taken together, these results suggest that lexical retrieval may be selectively impaired in bilinguals within those conditions where semantic competition is higher, i.e.,- in their non-dominant language; this could possibly be explained by an excessive amount of inhibition placed upon this language. Moreover, lexico-semantic impairments seem to be at least somewhat related to conflict monitoring deficits, suggesting a certain degree of overlap between EC and semantic control.
This study investigates the relationship between mechanisms involved in language control within dual- and single-language contexts by examining whether they are similarly impaired in bilingual PD patients. To do so, we explored the performance of bilingual individuals affected by PD and healthy controls on two linguistic tasks: between-language and within-language switching tasks. We focused on switch and mixing costs as measures of linguistic control.
The results indicate that, whereas larger switch costs were observed in PD patients, compared to controls, solely during the between-language task, larger mixing costs appeared during both the between-language task and the within-language task. These results are discussed within the framework of the dual mechanism hypothesis, which suggests that switch and mixing costs are measures of two types of control: specifically reactive and proactive control. Therefore, we conclude that reactive control for switching between languages is domain-specific while proactive control mechanisms are more domain-general.
Acquiring and speaking a second language increases demand on the processes of language control for bilingual as compared to monolingual speakers. Language control for bilingual speakers involves the ability to keep the two languages separated to avoid interference and to select one language or the other in a given conversational context. This ability is what we refer with the term “bilingual language control” (BLC). It is now well established that the architecture of this complex system of language control encompasses brain networks involving cortical and subcortical structures, each responsible for different cognitive processes such as goal maintenance, conflict monitoring, interference suppression, and selective response inhibition. Furthermore, advances have been made in determining the overlap between the BLC and the nonlinguistic executive control networks, under the hypothesis that the BLC processes are just an instantiation of a more domain‐general control system. Here, we review the current knowledge about the neural basis of these control systems. Results from brain imaging studies of healthy adults and on the performance of bilingual individuals with brain damage are discussed. Acquiring and speaking a second language (L2) increases demand on the processes of language control for bilingual as compared to monolingual speakers. Language control for bilingual speakers involves the ability to keep the two languages separated to avoid interference and to select one language or the other in a given conversational context. Here, we review the current knowledge about the neural basis of these control systems. Results from brain imaging studies of healthy adults and on the performance of bilingual individuals with brain damage are discussed.
Language research has provided insight into how speakers translate a thought into a sequence of sounds that ultimately becomes words, phrases, and sentences. Despite the complex stages involved in this process, relatively little is known about how we avoid and handle production and comprehension errors that would otherwise impede communication. We review current research on the mechanisms underlying monitoring and control of the language system, especially production, with particular emphasis on whether such monitoring is issued by domain-general or domain-specific procedures.
Two types of theoretical account have been proposed to explain the phenomenon of category-specific impairment in tests of semantic memory: One stresses the importance of different cortical regions to the representation of living and nonliving categories, while the other emphasize the importance of statistical relationships among features of concepts belonging to these two broad semantic domains. Theories of the latter kind predict that the direction of a domain advantage will be determined in large part by the overall damage to the semantic system, and that the profiles of patients with progressive impairments of semantic memory are likely to include a point at which an advantage for one domain changes to an advantage for the other. The present series of three studies employed semantic test data from two separate cohorts of patients with probable dementia of Alzheimer's type (DAT) to look for evidence of such a crossover. In the first study, longitudinal test scores from a cohort of 58 patients were examined to confirm the presence of progressive semantic deterioration in this group. In the second study, Kaplan-Meier survival curves based on serial naming responses and plotted separately for items belonging to living and nonliving domains indicated that the representations of living concepts (as measured by naming) deteriorated at a consistently and significantly faster rate than those of nonliving concepts. A third study, carried out to look in detail at the performance of mildly affected patients, employed an additional cross-sectional cohort of 20 patients with mild DAT and utilized a graded naming assessment. This study also revealed no evidence for a crossover in the advantage of one domain over the other as a function of disease severity. Taken together with the model of anatomical progression in DAT based on the work of Braak and Braak (1991), these findings are interpreted as evidence for the importance of regional cerebral anatomy to the genesis of semantic domain effects in DAT.
Until recently, cognitive science virtually ignored the fact that most people of the world are bilingual. During the past ten years this situation has changed markedly. There is now an appreciation that learning and using more than one language is the more natural circumstance of cognition. As a result, there is a wealth of new research on second-language learning and bilingualism that provides not only crucial evidence for the universality of cognitive principles, but also an important tool for revealing constraints within the cognitive architecture. In this volume, Judith Kroll and Annette de Groot have brought together the scientists at the forefront of research on second-language learning and bilingualism to present chapters that, rather than focusing simply on their own research, provide the first comprehensive overviews of this emerging field. Bilingualism provides a lens through which each of the central questions about language and cognition can be viewed. The five sections of this book focus on different facets of those questions: How is language acquired when infants are exposed to multiple-language input from birth, and how is it acquired when adults are required to learn a second language after early childhood? How do adult bilinguals comprehend and produce words and sentences when their two languages are potentially always active and in competition with one another? What are the neural mechanisms that underlie proficient bilingualism? What are the general consequences of bilingualism for cognition and for language and thought? This handbook will be essential reading for cognitive psychologists, linguists, applied linguists, and educators who wish to better understand the cognitive basis of bilingualism and the logic of experimental and formal approaches to language science.
Background:
Episodic memory impairment is the core feature of typical Alzheimer's disease.
Objective:
To evaluate the performance of two commonly used verbal memory tests to detect mild cognitive impairment due to Alzheimer's disease (MCI-AD) and to predict progression to Alzheimer's disease dementia (AD-d).
Methods:
Prospective study of MCI patients in a tertiary memory disorder unit. Patients underwent an extensive neuropsychological battery including two tests of declarative verbal memory: The Free and Cued Selective Reminding Test (FCSRT) and the word list learning task from the Consortium to Establish a Registry for Alzheimer's disease (CERAD-WL). Cerebrospinal fluid (CSF) was obtained from all patients and MCI-AD was defined by means of the t-Tau/Ab1-42 ratio. Logistic regression analyses tested whether the combination of FCSRT and CERAD-WL measures significantly improved the prediction of MCI-AD. Progression to AD-d was analyzed in a Cox regression model.
Results:
A total of 202 MCI patients with a mean follow-up of 34.2±24.2 months were included and 98 (48.5%) met the criteria for MCI-AD. The combination of FCSRT and CERAD-WL measures improved MCI-AD classification accuracy based on CSF biomarkers. Both tests yielded similar global predictive values (59.9-65.3% and 59.4-62.8% for FCSRT and CERAD-WL, respectively). MCI-AD patients with deficits in both FCSRT and CERAD-WL had a faster progression to AD-d than patients with deficits in only one test.
Conclusions:
The combination of FCSRT and CERAD-WL improves the classification of MCI-AD and defines different prognostic profiles. These findings have important implications for clinical practice and the design of clinical trials.
This article provides a classification of primary progressive aphasia (PPA) and its 3 main variants to improve the uniformity of case reporting and the reliability of research results. Criteria for the 3 variants of PPA—nonfluent/agrammatic, semantic, and logopenic—were developed by an international group of PPA investigators who convened on 3 occasions to operationalize earlier published clinical descriptions for PPA subtypes. Patients are first diagnosed with PPA and are then divided into clinical variants based on specific speech and language features characteristic of each subtype. Classification can then be further specified as " imaging-supported " if the expected pattern of atrophy is found and " with definite pathology " if pathologic or genetic data are available. The working recommendations are presented in lists of features, and suggested assessment tasks are also provided. These recommendations have been widely agreed upon by a large group of experts and should be used to ensure consistency of PPA classification in future studies. Future collaborations will collect prospective data to identify relationships between each of these syndromes and specific biomarkers for a more detailed understanding of clinicopathologic correlations. Neurology ® 2011;76:1–1 GLOSSARY AD Alzheimer disease; FTLD frontotemporal lobar degeneration; PPA primary progressive aphasia. A progressive disorder of language associated with atrophy of the frontal and temporal regions of the left hemisphere was first described in the 1890s by Pick 1 and Serieux. 2 In the modern literature, Mesulam 3 described a series of cases with " slowly progressive aphasia, " subsequently renamed primary progressive aphasia (PPA). 4 Warrington 5 described a progressive disorder of semantic memory in 1975. This condition was also described by Snowden et al. 6 as semantic dementia. In the early 1990s, Hodges and colleagues 7 provided a comprehensive characterization of semantic dementia. Subsequently, Grossman et al. 8 described a different form of progressive language disorder, termed progressive nonfluent aphasia. A consensus meeting attempted to develop criteria for these conditions in relation to frontotemporal lobar degener-ation. 9 For about 2 decades, cases of PPA were generally categorized as semantic dementia or progressive nonfluent aphasia, or in some studies as " fluent " vs " nonfluent. " However, there were a number of PPA cases that did not seem to fit a binary classification, 10 and a third clinical *These authors contributed equally to this work.
This study explored possible reasons for the striking difference between digit span and word span in patients with semantic dementia. Immediate serial recall (ISR) of number and non-number words was examined in four patients. For every case, the recall of single-digit numbers was normal whereas the recall of non-number words was impaired relative to controls. This difference extended to multi-digit numbers, and remained even when frequency, imageability, word length, set size and size of semantic category were matched for the numbers and words. The advantage for number words also applied to the patients' reading performance. Previous studies have suggested that semantic memory plays a critical role in verbal short-term memory (STM) and reading: patients with semantic dementia show superior recall and reading of words that are still relatively well known compared to previously known but now semantically degraded words. Additional assessments suggested that this semantic locus was the basis of the patients' category-specific advantage for numbers. Comprehension was considerably better for number than non-number words. Number knowledge may be relatively preserved in semantic dementia because the cortical atrophy underlying the condition typically spares the areas of the parietal lobes thought to be crucial in numerical cognition but involves the inferolateral temporal-lobes known to support general conceptual knowledge.
The processes required for object naming were addressed in a study of patients with semantic dementia (a selective decline of semantic memory resulting from progressive temporal lobe atrophy) and in a computational model of single-word production. Although all patients with semantic dementia are impaired in both single-word production and comprehension, previous reports had indicated two different patterns: (a) a parallel decline in accuracy of naming and comprehension, with frequent semantic naming errors, suggesting a purely semantic basis for the anomia and (b) a dramatic progressive anomia without commensurate decline in comprehension, which might suggest a mainly postsemantic source of the anomia. Longitudinal data for 16 patients with semantic dementia reflected these two profiles, but with the following additional important specifications: (1) despite a few relatively extreme versions of one or other profile, the full set of cases formed a continuum in the extent of anomia for a given degree of degraded comprehension; (2) the degree of disparity between these two abilities was associated with relative asymmetry in laterality of atrophy: a parallel decline in the two measures characterized patients with greater right-than left-temporal atrophy, while disproportionate anomia occurred with a predominance of atrophy in the left-temporal lobe. In an implemented computational model of naming, semantic representations were distributed across simulated left-and right-temporal regions, but the semantic units on the left were more strongly connected to left-lateralized phonolo-gical representations. Asymmetric damage to semantic units reproduced the longitudinal patient profiles of naming relative to comprehension, plus additional characteristics of the patients' naming performance. On the basis of both the neuropsychological and computational evidence, we propose that semantic impairment alone can account for the full range of word production deficits described here. &