The contribution of set switching and working memory to sentence processing in older adults

Task Demands and Sentence Reading Comprehension among Healthy Older Adults: The Complementary Roles of Cognitive Reserve and Working Memory

Ageing entails different functional brain changes. Education, reading experience, and leisure activities, among others, might contribute to the maintenance of cognitive performance among older adults and are conceptualised as proxies for cognitive reserve. However, ageing also conveys a depletion of working memory capacity, which adversely impacts language comprehension. This study investigated how cognitive reserve proxies and working memory jointly predict the performance of healthy older adults in a sentence reading comprehension task, and how their predictive value changes depending on sentence structure and task demands. Cognitively healthy older adults (n = 120) completed a sentence–picture verification task under two conditions: concurrent viewing of the sentence and picture or their sequential presentation, thereby imposing greater demands on working memory. They also completed a questionnaire on cognitive reserve proxies as well as a verbal working memory test. The sentence structure was manipulated by altering the canonical word order and modifying the amount of propositional information. While the cognitive reserve was the main predictor in the concurrent condition, the predictive role of working memory increased under the sequential presentation, particularly for complex sentences. These findings highlight the complementary roles played by cognitive reserve and working memory in the reading comprehension of older adults.

Demographic Effects on Longitudinal Semantic Processing, Working Memory, and Cognitive Speed

OBJECTIVES

To better understand and compare effects of aging and education across domains of language and cognition, we investigated whether (a) these domains show different associations with age and education, (b) these domains show similar patterns of age-related change over time, and (c) education moderates the rate of decline in these domains.

METHOD

We analyzed data from 306 older adults aged 55-85 at baseline of whom 116 returned for follow-up 4-8 years later. An exploratory factor analysis identified domains of language and cognition across a range of tasks. A confirmatory factor analysis analyzed cross-sectional associations of age and education with these domains. Subsequently, mixed linear models analyzed longitudinal change as a function of age and moderation by education.

RESULTS

We identified 2 language domains, that is, semantic control and semantic memory efficiency, and 2 cognitive domains, that is, working memory and cognitive speed. Older age negatively affected all domains except semantic memory efficiency, and higher education positively affected all domains except cognitive speed at baseline. In language domains, a steeper age-related decline was observed after age 73-74 compared to younger ages, while cognition declined linearly with age. Greater educational attainment did not protect the rate of decline over time in any domain.

DISCUSSION

Separate domains show varying effects of age and education at baseline, language versus cognitive domains show dissimilar patterns of age-related change over time, and education does not moderate the rate of decline in these domains. These findings broaden our understanding of age effects on cognitive and language abilities by placing observed age differences in context.

Propiedades psicométricas y datos normativos de la prueba ECCO_Senior: un instrumento para evaluar la comprensión gramatical en adultos mayores

El test ECCO_Senior se diseñó para evaluar la comprensión de oraciones en adultos mayores. Es una prueba corta y de fácil aplicación, que se ha empleado en distintos estudios previos. En el estudio participaron 670 personas, de 50 a 85 años de edad, que cumplían criterios de inclusión relativos al estatus cognitivo general, el estado de ánimo y porcentaje mínimo de aciertos en el test. Además de los test de cribado (MEC y GDS-15) y un cuestionario socio-demográfico, se aplicó a todos los participantes el test ECCO_Senior con el que se pueden obtener distintos índices (generales y específicos). Además de comprobar si existen diferencias entre los grupos según la edad y el nivel educativo, se evaluaron las propiedades psicométricas del test, incluyendo evidencias de validez en las que se probó la bondad de ajuste de tres modelos estructurales que sirven para identificar los índices que explican un mayor porcentaje de la varianza del constructo (comprensión de oraciones). Se ofrecen normas interpretativas del test por edad y nivel de estudios en los Apéndices. Los resultados indican que el test permite evaluar la comprensión de oraciones con una fiabilidad adecuada y es sensible a las dificultades que puede experimentar un adulto al realizar esta tarea. Los tres modelos muestran un buen ajuste y permiten concluir que las oraciones no ajustadas al orden sintáctico canónico y los distractores léxicos (si se considera el tipo de ítem) serían los mejores indicadores en términos del porcentaje de la varianza del constructo que explican.

Executive functions and components of oral reading fluency through the lens of text complexity

As readers struggle to coordinate various reading- and language-related skills during oral reading fluency (ORF), miscues can emerge, especially when processing complex texts. Following a miscue, students often self-correct as a strategy to potentially restore ORF and online linguistic comprehension. Executive functions (EF) are hypothesized to play an interactive role during ORF. Yet, the role of EF in self-corrections while reading complex texts remains elusive. To this end, we evaluated the relation between students' probability of self-correcting miscues-or P(SC)-and their EF profile in a cohort of 143 participants (aged 9-15) who represented a diverse spectrum of reading abilities. Moreover, we used experimentally-manipulated passages (decoding, vocabulary, syntax, and cohesion) and employed a fully cross-classified mixed-effects multilevel regression strategy to evaluate the interplay between components of ORF, EF, and text complexity. Our results revealed that, after controlling for reading and language abilities, increased production of miscues across different passage conditions was explained by worse EF. We also found that students with better EF exhibited greater P(SC) when reading complex texts. While text complexity taxes students' EF and influences their production of miscues, findings suggest that EF may be interactively recruited to restore ORF via self-correcting oral reading errors. Overall, our results suggest that domain-general processes (e.g., EF) are associated with production of miscues and may underlie students' behavior of self-corrections, especially when reading complex texts. Further understanding of the relation between different components of ORF and cognitive processes may inform intervention strategies to improve reading proficiency and overall academic performance.

Readers Recruit Executive Functions to Self-Correct Miscues During Oral Reading Fluency

Reading fluency undoubtedly underlies reading competence; yet, the role of executive functions (EF) is less well understood. Here, we investigated the relationship between children's reading fluency and EF. Children's (n = 82) reading and language performance was determined by standardized assessments and EF by parental questionnaire. Results revealed that production of more miscues was explained by poorer reading and language performance and EF. Yet, self-correcting a miscue was predicted by better EF, beyond reading and language abilities. Intriguingly, EF partially mediated the relationship between reading and self-correction, suggesting that self-correction reflects parallel recruitment and coordination of domain-specific and domain-general processes.

How cognitive reserve influences older adults' cognitive state, executive functions and language comprehension: A structural equation model

Cognitive reserve has been defined as the individuals' ability to tolerate age-related and neurodegenerative changes in the brain without developing clinical symptoms or signs of disease. Formal education, occupational attainment, and knowledge of other languages have been assessed as the most relevant factors determining cognitive reserve. The main objective of this study was to develop a structural equation model that reflects the direct influence of cognitive reserve on old adults' general cognitive status and executive functioning, and indirectly on sentence comprehension performance through executive functions mediation. One hundred and fifty eight Spanish-speaking older adults, cognitively intact, were assessed to obtain cognitive reserve data, general cognitive status, executive functioning (inhibitory control, working memory and cognitive flexibility), and sentence comprehension measures. High indicators of adjustment of the proposed model were obtained. The most related factors to cognitive reserve were education and occupational attainment. As we hypothesize, cognitive reserve had a higher direct significant relation to cognitive status and, in a lesser extent, to executive functioning. Participants' general cognitive status and executive function were high and directly related. Furthermore, cognitive reserve has an indirect positive relation to sentence comprehension via executive functions' mediation.

The Role of Executive Functions in Object- and Action-Naming among Older Adults

Background/Study Context: Lexical retrieval abilities and executive function skills decline with age. The extent to which these processes might be interdependent remains unknown. The aim of the current study was to examine whether individual differences in three executive functions (shifting, fluency, and inhibition) predicted naming performance in older adults. Methods: The sample included 264 adults aged 55-84. Six measures of executive functions were combined to make three executive function composites scores. Lexical retrieval performance was measured by accuracy and response time on two tasks: object naming and action naming. We conducted a series of multiple regressions to test whether executive function performance predicts naming abilities in older adults. Results: We found that different executive functions predicted naming speed and accuracy. Shifting predicted naming accuracy for both object and action naming while fluency predicted response times on both tests as well as object naming accuracy, after controlling for education, gender, age, working memory span, and speed of processing in all regressions. Interestingly, inhibition did not contribute to naming accuracy or response times on either task. Conclusion: The findings support the notion that preservation of some executive functions contributes to successful naming in older adults and that different executive functions are associated with naming speed and accuracy.

The Influence of Linguistic Demand on Symptom Expression in Adductor Spasmodic Dysphonia

INTRODUCTION

Adductor Spasmodic Dysphonia (ADSD), a form of focal dystonia, has been defined as a neurogenic, task-specific disorder characterized by abrupt spasms of intrinsic laryngeal muscles that result in phonatory breaks. Voice breaks are typically isolated to propositional speech, and reported to increase in severity as speaking demand or complexity increases. Research to date has focused on variations in phonologic contexts and their influence on voice breaks. The influences of variables at lexical and syntactic levels of analysis have been less well-researched and yet may provide insight into observed variability of symptom manifestation in this rare voice disorder.

OBJECTIVES

This study investigated frequency of voice breaks over 20 standard sentences in 38 individuals with ADSD according to linguistic complexity measures including lexical density and a four-level lexical frequency and type paradigm. Two research questions about linguistic influences and ADSD symptom manifestation were posed: (1) does the frequency of voice breaks vary according to the lexical density of a string? and (2) does the frequency of voice breaks vary according to a measure of lexical frequency/type?

RESULTS

Results revealed a nonsignificant relationship between string length and voice break frequency, whereas a significant relationship was found between lexical density and voice break frequency (P = 0.029, r = 0.488). Lexical analysis results revealed a significant relationship between lexical frequency and voice breaks, with words within technical/academic classes relating to the highest rates of voice break across 38 subjects with ADSD.

CONCLUSIONS

Results from this secondary analysis provide support for the hypothesis that variation in linguistic demand may modulate symptom expression in SD. Specifically, lexical density and lexical frequency modulated the frequency of symptom expression in classic forms of SD in this purposive sample.

Sentence Processing in Aphasia: An Examination of Material-Specific and General Cognitive Factors

The purpose of this study was to characterize further the nature of sentence processing deficits in acquired aphasia. Adults with aphasia and age-and education-matched adults with no brain damage completed a battery of formal cognitive-linguistic tests and an experimental sentence judgment task, which was performed alone and during focused attention and divided attention or dual-task conditions. The specific aims were to determine whether (a) increased extra-linguistic cognitive demands (i.e., focused and divided conditions) differentially affected the sentence judgement performances of the aphasic and control groups, (b) increased extra- linguistic cognitive demands interact with stimulus parameters (i.e., syntactic complexity, number of propositions) known to influence sentence processing, and (c) syntactic- or material specific resource limitations (e.g., sentence judgment in isolation), general cognitive abilities (e.g., short-term and working memory test scores), or both share a significant relationship with dual-task outcomes. Accuracy, grammatical sensitivity, and reaction time findings were consistent with resource models of aphasia and processing accounts of aphasic syntactic limitations, underscoring the theoretical and clinical importance of acknowledging and specifying the strength and nature of interactions between linguistic and extra-linguistic cognitive processes in not only individuals with aphasia, but also other patient and typical aging populations.

Breathe Easy, Speak Easy: Pulmonary Function and Language Performance in Aging

BACKGROUND

This study explored the association between pulmonary function (PF) and older adults' language performance accuracy. Study rationale was anchored in aging research reporting PF as a reliable risk factor affecting cognition among the elderly.

METHODS

180 adult English native speakers aged 55 to 84 years participated in the study. PF was measured through forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and FEV1/FVC ratio (FFR). Language performance was assessed with an action naming test and an object naming test, and two tests of sentence comprehension, one manipulating syntactic complexity and the other, semantic negation. Greater PF was predicted to be positively associated with all tasks.

RESULTS

Unadjusted models revealed FVC and FEV1 effects on language performance among older adults. Participants with higher FVC showed better naming on both tasks and those with higher FEV1 had better object naming only. In covariate-adjusted models, only a positive FVC-object naming association remained.

CONCLUSION

Findings were discussed in terms of brain oxygenation mechanisms, whereby good PF may implicate efficient oxygenation, supporting neurotransmitter metabolism that protects against neural effects of cerebrovascular risk. Effects on object naming were linked to putative differential oxygenation demands across language tasks.

How older adults use cognition in sentence-final word recognition

This study examined the effects of executive control and working memory on older adults' sentence-final word recognition. The question we addressed was the importance of executive functions to this process and how it is modulated by the predictability of the speech material. To this end, we tested 173 neurologically intact adult native English speakers aged 55-84 years. Participants were given a sentence-final word recognition test in which sentential context was manipulated and sentences were presented in different levels of babble, and multiple tests of executive functioning assessing inhibition, shifting, and efficient access to long-term memory, as well as working memory. Using a generalized linear mixed model, we found that better inhibition was associated with higher accuracy in word recognition, while increased age and greater hearing loss were associated with poorer performance. Findings are discussed in the framework of semantic control and are interpreted as supporting a theoretical view of executive control which emphasizes functional diversity among executive components.

Effects of metabolic syndrome on language functions in aging

This study explored effects of the metabolic syndrome (MetS) on language in aging. MetS is a constellation of five vascular and metabolic risk factors associated with the development of chronic diseases and increased risk of mortality, as well as brain and cognitive impairments. We tested 281 English-speaking older adults aged 55-84, free of stroke and dementia. Presence of MetS was based on the harmonized criteria (Alberti et al., 2009). Language performance was assessed by measures of accuracy and reaction time on two tasks of lexical retrieval and two tasks of sentence processing. Regression analyses, adjusted for age, education, gender, diabetes, hypertension, and heart disease, demonstrated that participants with MetS had significantly lower accuracy on measures of lexical retrieval (action naming) and sentence processing (embedded sentences, both subject and object relative clauses). Reaction time was slightly faster on the test of embedded sentences among those with MetS. MetS adversely affects the language performance of older adults, impairing accuracy of both lexical retrieval and sentence processing. This finding reinforces and extends results of earlier research documenting the negative influence of potentially treatable medical conditions (diabetes, hypertension) on language performance in aging. The unanticipated finding that persons with MetS were faster in processing embedded sentences may represent an impairment of timing functions among older individuals with MetS.

Language dominance and inhibition abilities in bilingual older adults

This study aimed to examine the so-called bilingual advantage in older adults' performance in three cognitive domains and to identify whether language use and bilingual type (dominant vs. balanced) predicted performance. The participants were 106 Spanish-English bilinguals ranging in age from 50 years to 84 years. Three cognitive domains were examined (each by a single test): inhibition (the Simon task), alternating attention (the Trail Making test), and working memory (Month Ordering). The data revealed that age was negatively correlated to performance in each domain. Bilingual type - balanced vs. dominant - predicted performance and interacted with age only on the inhibition measure (the Simon task). Balanced bilinguals showed age-related inhibition decline (i.e., greater Simon effect with increasing age); in contrast, dominant bilinguals showed little or no age-related change. The findings suggest that bilingualism may offer cognitive advantage in older age only for a subset of bilinguals.

The effect of plausibility on sentence comprehension among older adults and its relation to cognitive functions

BACKGROUND/STUDY CONTEXT: Older adults show age-related decline in complex-sentence comprehension. This has been attributed to a decrease in cognitive abilities that may support language processing, such as working memory (e.g., Caplan, DeDe, Waters, & Michaud, 2011,Psychology and Aging, 26, 439-450). The authors examined whether older adults have difficulty comprehending semantically implausible sentences and whether specific executive functions contribute to their comprehension performance.

METHODS

Forty-two younger adults (aged 18-35) and 42 older adults (aged 55-75) were tested on two experimental tasks: a multiple negative comprehension task and an information processing battery.

RESULTS

Both groups, older and younger adults, showed poorer performance for implausible sentences than for plausible sentences; however, no interaction was found between plausibility and age group. A regression analysis revealed that inhibition efficiency, as measured by a task that required resistance to proactive interference, predicted comprehension of implausible sentences in older adults only. Consistent with the compensation hypothesis, the older adults with better inhibition skills showed better comprehension than those with poor inhibition skills.

CONCLUSION

The findings suggest that semantic implausibility, along with syntactic complexity, increases linguistic and cognitive processing loads on auditory sentence comprehension. Moreover, the contribution of inhibitory control to the processing of semantic plausibility, particularly among older adults, suggests that the relationship between cognitive ability and language comprehension is strongly influenced by age.

Brain and language: evidence for neural multifunctionality

This review paper presents converging evidence from studies of brain damage and longitudinal studies of language in aging which supports the following thesis: the neural basis of language can best be understood by the concept of neural multifunctionality. In this paper the term "neural multifunctionality" refers to incorporation of nonlinguistic functions into language models of the intact brain, reflecting a multifunctional perspective whereby a constant and dynamic interaction exists among neural networks subserving cognitive, affective, and praxic functions with neural networks specialized for lexical retrieval, sentence comprehension, and discourse processing, giving rise to language as we know it. By way of example, we consider effects of executive system functions on aspects of semantic processing among persons with and without aphasia, as well as the interaction of executive and language functions among older adults. We conclude by indicating how this multifunctional view of brain-language relations extends to the realm of language recovery from aphasia, where evidence of the influence of nonlinguistic factors on the reshaping of neural circuitry for aphasia rehabilitation is clearly emerging.

Psycholinguistics of Aphasia Pharmacotherapy: Asking the Right Questions

BACKGROUND

Among the obstacles to demonstrating efficacy of pharmacological intervention for aphasia is quantifying patients' responses to treatment in a statistically valid and reliable manner. In many of the review papers on this topic (e.g., Berthier et al., 2011; de Boissezon, Peran, de Boysson, & Démonet, 2007; Small & Llano, 2009), detailed discussions of various methodological problems are highlighted, with some suggestions on how these shortcomings should be addressed. Given this deep understanding of caveats associated with the experimental design of aphasia pharmacotherapy studies (e.g., Berthier et al., 2011), investigations continue to produce inconsistent results.

AIM

In this review paper we suggest that inclusion of theory-driven linguistic measures in aphasia pharmacotherapy studies would add an important step toward elucidating precise patterns of improvement in language performance resulting from pharmacotherapeutic intervention.

MAIN CONTRIBUTION

We provide a brief review of the clinical approaches currently used in pharmacotherapy studies of aphasia, which often lack psycholinguistic grounding. We then present ways in which psycholinguistic models can complement this approach, offering a rationale for task selection, and as a result, lead to a better understanding of treatment effects. We then follow with an example of how such an integrative approach can be implemented in studies targeting stress reduction in people with aphasia, via beta-blocking agents, as a means to augment language performance, using the psycholinguistic framework of "linguistic anxiety" outlined in Cahana-Amitay et al, 2011 as our guideline.

CONCLUSION

We conclude that the incorporation of psycholinguistic models into aphasia pharmacotherapy studies can increase the resolution with which we can identify functional changes.

Effects of hypertension and diabetes on sentence comprehension in aging

OBJECTIVES

To assess the impact of hypertension and diabetes mellitus on sentence comprehension in older adults.

METHOD

Two hundred and ninety-five adults aged 55 to 84 (52% men) participated in this study. Self-report mail survey combined with medical evaluations were used to determine eligibility. Multiple sources were used to determine whether hypertension and diabetes were present or absent and controlled or uncontrolled. Sentence comprehension was evaluated with two tasks: embedded sentences (ES) and sentences with multiple negatives (MN). Outcome measures were percent accuracy and mean reaction time of correct responses on each task.

RESULTS

Regression models adjusted for age, gender, and education showed that the presence of hypertension impaired comprehension on the multiple negatives task (p < .01), whereas the presence of diabetes impaired the comprehension of embedded sentences (p < .05). Uncontrolled diabetes significantly impaired accurate comprehension of sentences with multiple negatives (p < .05). No significant patterns were found for reaction time.

DISCUSSION

The presence of hypertension and diabetes adversely affected sentence comprehension, but the relative contribution of each was different. These findings support the researchers' earlier speculations on the neurobiological mechanisms underlying the effects of hypertension and diabetes on language and cognition in aging. Uncontrolled disease status demonstrated more complicated age-related effects on sentence processing, highlighting the clinical importance for cognitive aging of identifying and managing vascular risk factors.

Bilateral brain regions associated with naming in older adults

To determine structural brain correlates of naming abilities in older adults, we tested 24 individuals aged 56-79 on two confrontation-naming tests (the Boston Naming Test (BNT) and the Action Naming Test (ANT)), then collected from these individuals structural Magnetic-Resonance Imaging (MRI) and Diffusion Tensor Imaging (DTI) data. Overall, several regions showed that greater gray and white matter volume/integrity measures were associated with better task performance. Left peri-Sylvian language regions and their right-hemisphere counterparts, plus left mid-frontal gyrus correlated with accuracy and/or negatively with response time (RT) on the naming tests. Fractional anisotropy maps derived from DTI showed robust positive correlations with ANT accuracy bilaterally in the temporal lobe and in right middle frontal lobe, as well as negative correlations with BNT RT, bilaterally, in the white matter within middle and inferior temporal lobes. We conclude that those older adults with relatively better naming skills can rely on right-hemisphere peri-Sylvian and mid-frontal regions and pathways, in conjunction with left-hemisphere peri-Sylvian and mid-frontal regions, to achieve their success.