Bilinguals who stutter: A cognitive perspective

PurposeBrain differences, both in structure and executive functioning, have been found in both developmental stuttering and bilingualism. However, the etiology of stuttering remains unknown. The early suggestion that stuttering is a result of brain dysfunction has since received support from various behavioral and neuroimaging studies that have revealed functional and structural brain changes in monolinguals who stutter (MWS). In addition, MWS appear to show deficits in executive control. However, there is a lack of data on bilinguals who stutter (BWS). This literature review is intended to provide an overview of both stuttering and bilingualism as well as synthesize areas of overlap among both lines of research and highlight knowledge gaps in the current literature.MethodsA systematic literature review on both stuttering and bilingualism studies was conducted, searching for articles containing “stuttering” and/or “bilingualism” and either “brain”, “executive functions”, “executive control”, “motor control”, “cognitive reserve”, or “brain reserve” in the PubMed database. Additional studies were found by examining the reference list of studies that met the inclusion criteria.ResultsA total of 148 references that met the criteria for inclusion in this paper were used in the review. A comparison of the impact of stuttering or bilingualism on the brain are discussed.ConclusionPrevious research examining a potential bilingual advantage for BWS is mixed. However, if such an advantage does exist, it appears to offset potential deficits in executive functioning that may be associated with stuttering.     

Cerebral White Matter Integrity and Cognitive Aging: Contributions from Diffusion Tensor Imaging

The integrity of cerebral white matter is critical for efficient cognitive functioning, but little is known regarding the role of white matter integrity in age-related differences in cognition. Diffusion tensor imaging (DTI) measures the directional displacement of molecular water and as a result can characterize the properties of white matter that combine to restrict diffusivity in a spatially coherent manner. This review considers DTI studies of aging and their implications for understanding adult age differences in cognitive performance. Decline in white matter integrity contributes to a disconnection among distributed neural systems, with a consistent effect on perceptual speed and executive functioning. The relation between white matter integrity and cognition varies across brain regions, with some evidence suggesting that age-related effects exhibit an anterior–posterior gradient. With continued improvements in spatial resolution and integration with functional brain imaging, DTI holds considerable promise, both for theories of cognitive aging and for translational application.     

Age-related changes in ongoing thought relate to external context and individual cognition

Understanding how age-related changes in cognition manifest in the real world is an important goal. One means of capturing these changes involves “experience sampling” participant’s self-reported thoughts. Research has shown age-related changes in ongoing thought: e.g., older adults have fewer thoughts unrelated to the here-and-now. However, it is currently unclear how these changes reflect cognitive aging or lifestyle changes. 78 younger adults and 35 older adults rated their thought contents along 20 dimensions and the difficulty of their current activity in their daily lives. They also performed cognitive tasks in the laboratory. In a set of exploratory analyses, we found that older adults spent more time thinking positive, wanted thoughts, particularly in demanding contexts, and less time mind wandering about their future selves. Past-related thought related to episodic memory differently in older and younger adults. These findings inform the use of experience sampling to understand cognitive aging.     

A dynamic view of cultural influence: A review

Static models of culture's influence have given way to a dynamic view, which identifies not only differences across cultures in people's judgments and decisions, but also the situations and conditions in which these differences do or do not appear. Theory and evidence developed from a cognitive psychological perspective underlie this dynamic approach, including research emerging from the “dynamic constructivist” and “situated cognition” models. In the present review, we focus on findings that confirm the utility of this cognitively oriented approach, and briefly discuss the advantages and complementary nature of the “social collective” and neuroscience approaches to understanding culture.     

Atrophy of the parietal lobe in preclinical dementia

Cortical grey matter atrophy patterns have been reported in healthy ageing and Alzheimer disease (AD), but less consistently in the parietal regions of the brain. We investigated cortical grey matter volume patterns in parietal areas. The grey matter of the somatosensory cortex, superior and inferior parietal lobule was measured in 75 older adults (38 cognitively stable and 37 individuals with cognitive decline after 3 years). Dementia screening 6 years after scanning resulted in nine AD cases from the cognitively stable (n=3) and cognitive decline group (n=6), who were assigned to a third group, the preclinical AD group. When regional differences in cortical volume in the parietal lobe areas were compared between groups, significant differences were found between either the cognitive decline or stable group on the one hand and preclinical AD individuals on the other hand in the inferior parietal lobule. Group membership was best predicted by the grey matter volume of the inferior parietal lobule, compared to the other parietal lobe areas. The parietal lobe was characterised by a differential atrophy pattern based on cognitive status, which is in agreement with the 'last-developed-first-atrophied' principle. Future studies should investigate the surplus value of the inferior parietal lobe as a potential marker for the diagnosis of AD compared to other brain regions, such as the medial temporal lobe and the prefrontal lobe.     

Capitalizing on cortical plasticity: influence of physical activity on cognition and brain function

Given the aging populations in many countries throughout the world, there is an increasing interest in lifestyle factors and interventions that will enhance the cognitive vitality of older adults and reduce the risk for age-related neurological disorders, such as Alzheimer's disease. In this review, we evaluate the hypothesis that physical activity and exercise might serve to protect, and also enhance, cognitive and brain function across the adult lifespan. To this end, we critically review three separate literatures that have examined the influence of physical activity and exercise on cognition, brain function and brain structure of adults, including epidemiological or prospective observational studies, randomized human clinical interventions and non-human animal studies. We suggest that this literature supports the claim that physical activity enhances cognitive and brain function, and protects against the development of neurodegenerative diseases. We discuss future directions to address currently unresolved questions, such as interactions between multiple lifestyle factors on offsetting or protecting against cognitive and neural decline, and conclude that physical activity is an inexpensive treatment that could have substantial preventative and restorative properties for cognitive and brain function.     

Cognitive Performance in Adults’ Daily Lives: Is There a Lab-Life Gap?

This article addresses the “lab-life gap” in cognitive aging research as an important issue of ecological validity in developmental research. Older adults often function competently in complex everyday situations despite age-related deficits on laboratory-based cognitive tasks. Therefore, to what extent do lab-based cognitive tasks predict real-life outcomes in older adults? Our review shows that although they are similar, measures of everyday cognitive competence predict relevant outcomes beyond basic measures. We provide our perspective on critical questions concerning the relevance of everyday cognitive tests in our ever-changing world, new methods of everyday cognitive assessment, and whether everyday cognition can be improved.     

DEVELOPMENTAL SEX DIFFERENCES IN THE RELATION OF NEUROANATOMICAL CONNECTIVITY TO INTELLIGENCE

Recent neuroimaging research has shown sex-related differences in the relationship between brain structure and cognitive function. Anatomical studies have shown a greater reliance for cognitive function on white matter structure in adult females, and a greater reliance on gray matter structure in adult males. Functional neuroimaging studies have also shown a greater correlation between brain connectivity and cognitive function in females. However, this relationship is not present in young childhood (5 years old) but appears during the developmental period. Here sex differences in structure–function relationships and their developmental trajectory are investigated using diffusion tensor imaging (DTI) on a large cohort of over 100 normal children ages 5–18. Significant sex–X–IQ interactions on fractional anisotropy (FA), a marker for white matter organization, were seen in the left frontal lobe, in fronto-parietal areas bilaterally, and in the arcuate fasciculus bilaterally, with girls showing positive correlations of FA with IQ, and boys showing a negative correlation. Significant sex–X–IQ–X–age interactions on FA were also seen in the left frontal lobe and in fronto-parietal areas bilaterally, showing a developmental effect. These results strongly corroborate previous findings regarding sex differences in structure–function relationships regarding intelligence. Results also indicate that a naïve interpretation of “more is better” with respect to FA may not be accurate, especially in adult males.     

Gist-based memory for prices and “better buys” in younger and older adults

Ageing typically leads to various memory deficits which results in older adults’ tendency to remember more general information and rely on gist memory. The current study examined if younger and older adults could remember which of two comparable grocery items (e.g., two similar but different jams) was paired with a lower price (the “better buy”). Participants studied lists of grocery items and their prices, in which the two items in each category were presented consecutively (Experiment 1), or separated by intervening items (Experiment 2). At test, participants were asked to identify the “better buy” and recall the price of both items. There were negligible age-related differences for the “better buy” in Experiment 1, but age-related differences were present in Experiment 2 when there were greater memory demands involved in comparing the two items. Together, these findings suggest that when price information of two items can be evaluated and compared within a short period of time, older adults can form stable gist-based memory for prices, but that this is impaired with longer delays. We relate the findings to age-related changes in the use of gist and verbatim memory when remembering prices, as well as the associative deficit account of cognitive ageing.     

Neurocognitive Aging and the Compensation Hypothesis

ABSTRACT— The most unexpected and intriguing result from functional brain imaging studies of cognitive aging is evidence for age-related overactivation: greater activation in older adults than in younger adults, even when performance is age-equivalent. Here we examine the hypothesis that age-related overactivation is compensatory and discuss the compensation-related utilization of neural circuits hypothesis (CRUNCH). We review evidence that favors a compensatory account, discuss questions about strategy differences, and consider the functions that may be served by overactive brain areas. Future research directed at neurocognitively informed training interventions may augment the potential for plasticity that persists into the later years of the human lifespan.     

Decline and Compensation in Aging Brain and Cognition: Promises and Constraints

Age-related cognitive declines are common and inevitable, but life trajectories of brain and cognitive functions are variable and plastic. To identify the mechanisms of decline, the prospects for improvement, and the constraints on the remedial approaches, the contributors of this special issuer examine several diverse areas of cognitive and brain aging: from structural and metabolic brain aging to genetics, and from age-sensitive cognitive domains to those that resist aging. In spite of such thematic diversity, several common threads are clear. To achieve better compensation for age-related changes in cognition, we need to understand their brain substrates, telling cognitively relevant from epiphenomenal. We also need to understand the sources of profound individual variability in aging trajectories, and to learn to tailor interventions to specific individual profiles of decline.     

Piagetian Studies of Cognitive Development in India

The paper presents a review of studies on cognitive development of children in India inspired by Piaget’s theory of cognitive development. Piaget’s theory is briefly introduced before examining its cross-cultural applications. Early studies of cognitive development, which focus on age-related changes in cognition, are described. These are followed by the studies of the last decades in which developmental contexts, such as those provided by ecology, culture, schooling, and various forms of training, are implicated. Studies of spatial cognition are discussed in some detail and points of convergence between findings of Indian studies and those reported by Piaget are critically examined. The issue of “performance” vs. “competence” is addressed and research evidence that considers performance difference as a matter of cognitive style is presented. Possible reasons for decline of research interest in Piagetian studies in recent years is examined and suggestion for future studies in this field are offered.     

Aging,memory loss,and Alzheimer’s disease: What do refugees from the former Soviet Union think?

ABSTRACT

Since the mid-1970s, approximately 700,000 émigrés from the former Soviet Union (FSU), most of Jewish descent, settled in the United States. Now, 25 or more years post-emigration, they have “aged in place” in the United States, but their values, beliefs, and attitudes about growing old, memory changes, and Alzheimer’s disease remain grounded in their earlier life experiences. Based on findings from a study of the social and cultural factors affecting beliefs about Alzheimer’s disease, aging, and memory loss, this article examines how past life experiences, the immigration experience, and cultural values affect Russian-speaking refugees’ beliefs and views about aging, memory loss, and Alzheimer’s disease.     

A Qualitative Investigation of Women's and Men's Body Image Concerns and Their Attitudes Toward Aging

In-depth interviews were conducted with 42 women and men (aged 22–62 years) to explore their relationships with their bodies. The particular focus was age-related changes in body image and attitudes toward the body aging, an area that has received little research attention to date. Thematic analysis revealed distinctive gender differences. Men commonly conceptualized their bodies as a holistic entity, whereas women commonly had compartmentalized conceptualizations. They also construed the importance of their bodies differently: men tended to focus on functionality, and women tended to focus on display. These findings may help to explain gendered consequences of body dissatisfaction. Accounts about the aging of the body support a “double standard of aging.” Women viewed aging most negatively in terms of its impact on appearance, whereas men reported a neutral or even positive impact on appearance.     

情景记忆成功年老化的神经机制

随着年龄的增长, 大部分老年人的情景记忆会出现衰退, 但也会有一部分老年人的情景记忆表现出成功的年老化, 即记忆成绩较好或随增龄的衰退程度较小。脑保持理论、神经去分化理论、认知储备理论以及神经补偿理论分别从不同角度解释了情景记忆成功年老化的神经机制。基于选择性优化与补偿模型对现有理论进行整合, 发现情景记忆成功年老化可能与个体的认知储备水平直接相关：高认知储备的老年人能够对情景记忆相关的脑区和脑网络进行优化且具备更强的神经补偿能力, 因而其脑功能(比如, 神经表征和神经加工通路的特异性)可能会保持地更好。未来研究需要更多地采用纵向设计来考察各理论之间的关系及其影响因素, 从而更好地解释记忆成功年老化的神经机制并为提升老年人的脑与认知健康提供支持。     

Effects of Hormone Replacement Therapy and Aging on Cognition: Evidence for Executive Dysfunction

ABSTRACT

The present study was designed to explore whether the frontal lobe hypothesis of cognitive aging may be extended to describe the cognitive effects associated with estrogen use in postmenopausal women. Postmenopausal estrogen-only users, estrogen + progesterone users, and non-users (60–80 years old), as well as young, regularly cycling women (18–30 years old) completed an item and source memory task. Since source memory is thought to rely more on executive processes than item memory, we hypothesized that aging and estrogen effects would be greater for source memory than for item memory. Neuropsychological tests explored whether the effects of aging and estrogen use were revealed on other tests of frontal lobe function. Results from the experimental task revealed greater aging and estrogen effects for source memory than for item memory, and neuropsychological results revealed aging and estrogen effects on a subset of tests of executive function. Women on estrogen + progesterone therapy did not outperform non-users, suggesting that the addition of progesterone to hormone therapy may mitigate the benefits induced by estrogen use alone. Overall, findings support the hypothesis that estrogen use may temper age-related cognitive decline by helping to maintain functions subserved by the frontal lobes.     

Structural constraints on process explanations in cognitive aging

Much of the current research in the area of cognitive aging has been focused on investigating specific processes presumed to be responsible for the age differences observed in particular cognitive tasks. A central thesis of this article is that age-related effects on cognitive variables seldom occur in isolation, and hence, they are best interpreted in the context of the structural interrelations that exist among variables and the relations of age on that organizational structure. Results from analyses of 2 separate data sets suggest that large proportions of the age-related effects across a wide range of cognitive variables are shared and that independent, or unique, age-related effects often contribute relatively little to the age differences observed in many cognitive variables. These findings imply that it is important to consider the structure within which a variable occurs when attempting to investigate the processes responsible for age-related differences on that variable.     

A Cross-Cultural and Developmental Analysis of Self-Esteem in Chinese and Western Children

In this review, we examine the construct of self-esteem from a cross-cultural perspective in Chinese and Western children and adolescents. We also explore the role of childrearing practices in the development of self-esteem in these different cultures. In doing so, we first review the concepts of emic (i.e., variations in patterns of behavior within a given culture) and etic research (i.e., variations in common patterns of behavior or activities across cultures). Then, we invoke Berry's notions of “imposed-etic” and “derived-etic” approaches (J. Berry, 1989) in understanding crucial cross-cultural differences that are evident in the literature. We pose basic questions such as: (1) What does self-esteem “look” like in Chinese children? (2) How do childrearing practices in China influence the development of self-esteem in children? And, (3) what are the limitations of cross-cultural research in understanding a phenomenon such as self-esteem? We suggest that self-esteem does not “mean” the same things across these collectivist and individualistic cultures. We conclude our discourse with specific recommendations for clinical theory, research, and practice.     

Only time will tell: cross-sectional studies offer no solution to the age-brain-cognition triangle: comment on Salthouse (2011)

Salthouse (2011) critically reviewed cross-sectional and longitudinal relations among adult age, brain structure, and cognition (ABC) and identified problems in interpretation of the extant literature. His review, however, missed several important points. First, there is enough disparity among the measures of brain structure and cognitive performance to question the uniformity of B and C vertices of the ABC triangle. Second, age differences and age changes in brain and cognition are often nonlinear. Third, variances and correlations among measures of brain and cognition frequently vary with age. Fourth, cross-sectional comparisons among competing models of ABC associations cannot disambiguate competing hypotheses about the structure and the range of directed and reciprocal relations between changes in brain and behavior. We offer the following conclusions, based on these observations. First, individual differences among younger adults are not useful for understanding the aging of brain and behavior. Second, only multivariate longitudinal studies, age-comparative experimental interventions, and a combination of the two will deliver us from the predicaments of the ABC triangle described by Salthouse. Mediation models of cross-sectional data represent age-related differences in target variables but fail to approximate time-dependent relations; thus, they do not elucidate the dimensions and dynamics of cognitive aging.     

A Game a Day Keeps Cognitive Decline Away? A Systematic Review and Meta-Analysis of Commercially-Available Brain Training Programs in Healthy and Cognitively Impaired Older Adults

Neuropsychology Review - The rising prevalence rates of age-related cognitive impairment are a worldwide public concern, bringing about a surge in the number of “brain training”...