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.     

Neuropsychological Differences Between Frontotemporal Dementia and Alzheimer's Disease: A Review

This paper surveys the similarities and differences between frontotemporal dementia (FTD) and Alzheimer's disease (AD). The review covers findings primarily from neuropsychological studies on memory, language, attention/executive function, and visuospatial abilities. However, neuropsychiatric and neuroimaging data are also briefly discussed. Distinguishing features of both FTD and AD are described in order to present a comprehensive clinical picture of these dementing diseases, which is essential for the process of differential diagnosis. The cause of specific cognitive deficits is also considered. Our comprehensive review of the empirical literature reveals that AD is characterized by early memory loss and visuospatial problems, while among the main features of FTD are behavioral abnormalities and executive dysfunctions.     

A case study of selective impairment of the central executive component of working memory after a focal frontal lobe damage

RC is a 36-year-old man who sustained a closed head injury with bilateral frontal lobe hypometabolism in 1978. In 1994, after a lobectomy of a large part of the left frontal lobe, he presented no behavioral disruption and normal performances on most of intelligence, long-term memory, and executive tests. However, he showed deficits in tasks that implicate short-term storage (i.e., span tasks). These deficits in working memory were explored with regard to Baddeley's model using computerized tasks. On these tasks RC showed normal functioning of the articulatory loops and dysfunction of the central executive component in dual tasks. These results confirm those reported in another single case study by Van Der Linden, Coyette, and Seron (1992) and indicate that dual-task performance may assess one separable feature of executive functions.     

Cerebellar-induced apraxic agraphia: a review and three new cases

Apraxic agraphia is a writing disorder due to a loss or lack of access to motor engrams that program the movements necessary to produce letters. Clinical and functional neuroimaging studies have demonstrated that the neural network responsible for writing includes the superior parietal region and the dorsolateral and medial premotor cortex. Recent studies of two cases with atypical lesion localisations in the left thalamus and the right cerebellum support the hypothesis that the written language network is larger than previously assumed. The aim of this study is twofold: (1) to provide a survey of cases of apraxic agraphia published between 1973 and June 2010, and (2) to provide further evidence for a role of the cerebellum in writing via three additional cases who presented with apraxic agraphia after ischemic damage in the cerebellum. Functional neuroimaging studies by means of brain perfusion SPECT showed perfusional deficits in the anatomoclinically suspected supratentorial areas, subserving language dynamics, syntax, naming, writing and executive functioning.     

Control networks and neuromodulators of early development

In adults, most cognitive and emotional self-regulation is carried out by a network of brain regions, including the anterior cingulate, insula, and areas of the basal ganglia, related to executive attention. We propose that during infancy, control systems depend primarily upon a brain network involved in orienting to sensory events that includes areas of the parietal lobe and frontal eye fields. Studies of human adults and alert monkeys have shown that the brain network involved in orienting to sensory events is moderated primarily by the nicotinic cholinergic system arising in the nucleus basalis. The executive attention network is primarily moderated by dopaminergic input from the ventral tegmental area. A change from cholinergic to dopaminergic modulation would be a consequence of this switch of control networks and may be important in understanding early development. We trace the attentional, emotional, and behavioral changes in early development related to this developmental change in regulative networks and their modulators.     

The Impact of Neuropsychological Deficits on Functional Stroke Outcomes

This review examines the available literature on neuropsychological outcomes of stroke and the literature on the ability of specific areas of neuropsychological deficit to predict functional stroke outcome. The literature reviewed indicates that post-stroke deficits in executive function, memory, language, and speed of processing are common, with those identified as having progressive ‘post-stroke dementia’ presenting with a similar, though more impaired profile, with increased impairments particularly noted in the area of memory. It is clear that some aspects of neuropsychological functioning (e.g., presence of neglect, aphasia, anosognosia; and verbal memory and attention deficits) show promise as a means of predicting post-stroke functional outcomes. Examining the available literature, it becomes evident that there is a need for long-term, large scale (i.e., population based) follow-up studies, evaluating likely long-term neuropsychological outcomes of stroke and their prognostic utility.     

The social motivation theory of autism

The idea that social motivation deficits play a central role in Autism Spectrum Disorders (ASD) has recently gained increased interest. This constitutes a shift in autism research, which has traditionally focused more intensely on cognitive impairments, such as theory-of-mind deficits or executive dysfunction, and has granted comparatively less attention to motivational factors. This review delineates the concept of social motivation and capitalizes on recent findings in several research areas to provide an integrated account of social motivation at the behavioral, biological and evolutionary levels. We conclude that ASD can be construed as an extreme case of diminished social motivation and, as such, provides a powerful model to understand humans' intrinsic drive to seek acceptance and avoid rejection.     

Executive control emerging from dynamic interactions between brain systems mediating language, working memory and attentional processes

In this theoretical paper, we review findings from a series of recent behavioral and functional neuroimaging studies of working memory and executive control which provide evidence for the following theses: 1. Working memory in humans is represented by two brain systems which differ from each other with respect to their functional-neuroanatomical organization and probably also with respect to their evolutionary origin. 2. One of these brain systems relies on prefronto-parietal and prefronto-temporal cortical networks that presumably also mediate attentional selection by the top-down modulation of domain-specific sensory association areas towards behaviorally relevant information. 3. The other system is implemented by mainly left-hemispheric premotor and parietal brain regions which to a greater part also underlie language functions and which may also be involved in the retrieval and maintenance of verbal goal representations during advance preparation for task switches. 4. Context-sensitive behavioral adaptation is supported by a complementary mechanism for the detection of conflicts and for the triggering of cognitive control processes that relies on parts of the medial frontal cortex. Based on these empirical results reported in the literature we propose a neurocognitive model of executive control according to which the human ability to flexibly adapt to changing behavioral requirements, i.e. executive control, depends on dynamic and context-sensitive interactions between these brain systems.     

Neurocognitive sequelae of pediatric sickle cell disease: a review of the literature.

This literature review summarizes all studies relating neuropsychological performance to neuroimaging findings in pediatric sickle cell disease (N=28; published 1991-2005). Although inconsistencies exist within and across domains, deficits in intelligence (IQ), attention and executive functions, memory, language, visuomotor abilities, and academic achievement have been identified. Overall neurocognitive compromise was revealed to be related to the level of neurological injury and the location of silent infarct. Attentional and executive dysfunction is prevalent and related to frontal lobe abnormalities.     

The Combined Effect of Neuropsychological and Neuropathological Deficits on Instrumental Activities of Daily Living in Older Adults: a Systematic Review

To date, studies have consistently demonstrated associations between either neuropsychological deficits or neuroanatomical changes and instrumental activities of daily living (IADL) in aging. Only a limited number of studies have evaluated morphological brain changes and neuropsychological test performance concurrently in relation to IADL in this population. As a result, it remains largely unknown whether these factors independently predict functional outcome. The current systematic review intended to address this lack of information by reviewing the literature on older adults, incorporating studies that examined e.g., normal aging, but also stroke or dementia patients. A comprehensive search of databases (Pubmed, Embase, Medline, Web of Science, PsycINFO) and reference lists was performed, focusing on papers in the English language that examined the combined effect of neuropsychological and neuroanatomical factors on IADL in samples of adults with an average age above 50. In total, 58 potential articles were identified; 20 were included in the review. The results show that especially neuropsychological variables (primarily memory and executive functions) independently predict IADL. Although some unique predictive value of brain morphological changes, such as hippocampal atrophy, was found, support for the importance of white matter changes was limited. However, the results of the studies reviewed are diverse, and appear to be at least partially determined by the variables included. For example, studies were less likely to find an independent effect of cognition if they solely employed a cognitive screening instrument. This indicates that a structured examination of neuroanatomical and neuropsychological correlates of IADL in different patient populations is warranted.     

脑岛在成瘾中的结构和功能异常

脑岛位于大脑外侧裂的深处, 与情绪和内感受等多种心理功能有关。脑岛在成瘾中的结构变化和功能连接异常, 表明了脑岛在成瘾中的作用, 刺激脑岛区域干预成瘾也逐渐成为研究者们关注的领域。未来的研究应该通过对脑岛进行精细分割和多种方法相结合来进一步考察脑岛在成瘾中的具体作用, 并挖掘不同成瘾类型的共性和特性, 以便更好开展基于脑的成瘾干预。     

Magnetic resonance perfusion imaging in the study of language

This paper provides a brief review of various uses of magnetic resonance perfusion imaging in the investigation of brain/language relationships. The reviewed studies illustrate how perfusion imaging can reveal areas of brain where dysfunction due to low blood flow is associated with specific language deficits, and where restoration of blood flow to improve the tissue function results in recovery of those deficits. This sort of evidence helps to reveal areas of the brain that are essential to a particular language task. Other studies have provided clues regarding the mechanisms of early language recovery, or have shown how perfusion imaging can identify patients with chronic hypoperfusion due to cerebrovascular stenosis in whom the BOLD effect in fMRI may be absent or reduced in areas of neural activation.     

Neurocognitive Sequelae of Pediatric Sickle Cell Disease: A Review of the Literature

This literature review summarizes all studies relating neuropsychological performance to neuroimaging findings in pediatric sickle cell disease (N=28; published 1991–2005). Although inconsistencies exist within and across domains, deficits in intelligence (IQ), attention and executive functions, memory, language, visuomotor abilities, and academic achievement have been identified. Overall neurocognitive compromise was revealed to be related to the level of neurological injury and the location of silent infarct. Attentional and executive dysfunction is prevalent and related to frontal lobe abnormalities.     

执行功能与精神分裂症

执行功能障碍是精神分裂症最重要的认知功能障碍,与精神分裂症其它方面的障碍有着密不可分的关系。文章在相关的认知神经心理学和临床研究的基础上,分别综述了精神分裂症执行功能障碍的特点、研究方法、相关脑机制,执行功能与注意、记忆等一般认知功能间的关系,执行功能与精神症状间的联系及其在诊断、康复、判断预后方面的作用等。对精神分裂症执行功能障碍的认识有助于更深入地理解其病因机制,并有利于临床评价与防治     

The Ontogenesis of Language Impairment in Autism: A Neuropsychological Perspective

Autistic Disorder (AD) is a phenotypically heterogeneous condition characterized by impairments in social interaction, communication, and the presence of repetitive behavior and restricted interests. It is a model syndrome to investigate neural interaction and integration at the nexus of language and social cognition. This paper considers the problems of language acquisition in AD from an evolutionary and ontogenetic context. Following a review of normal language development during the formative years of brain development, we examine what is known about infant linguistic and nonlinguistic precursors of language acquisition in AD and examine how anomalies of several processes relate to language abnormalities manifest by the early elementary school years. Population heterogeneity and practical limitations inherent to the study of children currently limit a comprehensive understanding of the significance of specific neurological abnormalities in relation to observed deficits. However, convergent evidence implicates anomalies of a widely distributed neural network, involving superior temporal sulcus, superior temporal gyrus, supramarginal gyrus, insula, inferior frontal gyrus, hippocampus, amygdala and cerebellum. These anomalies reflect the cumulative effects of genetic, epigenetic and environmental influences. Neuropsychological studies of language in AD provide an important means to define the phenotypic variation resulting from alterations in neural architecture. By mapping broad relationships between key symptoms, neuropsychological impairment and neural substrate, information derived from these studies enable a level of analysis that bridges the gap between the genome and the syndrome. Further study of children during the critical first 2 years of life using behavioral, electrophysiological, and functional neuroimaging methods is essential.     

Apathy in frontotemporal dementia: behavioral and neuroimaging correlates

We investigated the occurrence of goal-directed motivational change in the form of apathy in patients with frontotemporal dementia (FTD), particularly those with behavioral variant social and executive deficits (bvFTD). Standardized behavioral inventory was employed to survey and compare apathy ratings from patients and caregivers. In cases of bvFTD, apathy ratings were further related to measures of social cognition, executive function, and atrophy on brain MRI. Results indicated that caregivers rated bvFTD patients as having significantly elevated apathy scores though patient self-ratings were normal. Caregiver and self-ratings of FTD samples with progressive nonfluent aphasia and semantic dementia did not differ from healthy controls and their informants. In the bvFTD sample, caregiver apathy scores were not correlated with general cognitive screening or depression scores, but were significantly correlated with social cognition and executive function measures. Voxel-based morphometry revealed that apathy ratings in bvFTD were related to prominent atrophy in the right caudate (including the ventral striatum), the right temporo-parietal junction, right posterior inferior and middle temporal gyri, and left frontal operculum- anterior insula region. Findings suggest that bvFTD is associated with a significant breakdown in goal-directed motivated behavior involving disruption of cortical-basal ganglia circuits that is also related to social and executive function deficits.     

Formula: see text]Substance exposure in utero and developmental consequences in adolescence: A systematic review

Background: The impacts of maternal substance use have been observed in both research and clinical experience. Several studies have shown that preschool children are at heightened risk of developing various cognitive, behavioral, and socioemotional difficulties. Most knowledge has been generated concerning alcohol consumption during pregnancy and the postnatal effects thereof. Less is known about substance use other than alcohol (for instance, opiates, marijuana, and cocaine) during pregnancy and the long-term developmental consequences. Objective: The aims of this review are to identify relevant published data on adolescents who have been exposed in utero to alcohol and/or other substances and to examine developmental consequences across functions and mental health at this point in life. Methods: PubMed, Embase, and PsychInfo were searched for publications during the period of 1980-2011 and titles and abstracts selected according to prespecified broad criteria. Results: Twenty-five studies fulfilled all of the specific requirements and were included in this review. Most research covered prenatal alcohol exposure. Other substances, however, included cocaine, marijuana, opiates, and poly-substances. Results showed that prenatal exposure to alcohol has long-term cognitive, behavioral, social, and emotional developmental consequences depending on amount and timing of exposure in utero. Less evidence exists for long-term consequences of exposure in utero to other substances than alcohol. However, recent brain-imaging studies have provided important evidence of serious effects of other substance exposure on the developing brain and recent follow-up studies have found an association with deficits in language, attention, areas of cognitive performance and delinquent behavior in adolescence.     

Neuropsychological aspects of Parkinson's disease

The neuropsychological effects of Parkinson's disease have gained wide recognition in recent literature. Effects have been documented in almost all areas of cognitive functioning, including general intellectual functioning, visual-spatial functioning, executive functions, attention and memory functions, language functions, and affective processes. Visual-spatial functions, memory functions, and executive functions have received particular interest. This review of the literature is an attempt to tie together the large number of studies in these cognitive areas and to present a suggestion for a comprehensive neuropsychological battery tailored to the patient with Parkinson's disease. Throughout the review, factors relevant to Parkinson's disease, e.g., dementia, motor symptoms, and hemiparkinsonism, are considered.