Developmental Disabilities Research Reviews最新文献

Neuroimaging studies of Turner syndrome can advance our understanding of the X chromosome in brain development, and the modulatory influence of endocrine factors. There is increasing evidence from neuroimaging studies that TX individuals have significant differences in the anatomy, function, and metabolism of a number of brain regions; including the parietal lobe; cerebellum, amygdala, hippocampus; and basal ganglia; and perhaps differences in “connectivity” between frontal and parieto-occipital regions. Finally, there is preliminary evidence that genomic imprinting, sex hormones and growth hormone have significant modulatory effects on brain maturation in TS. © 2009 Wiley-Liss, Inc. Dev Disabil Res Rev 2009;15:279–283.

Fragile X syndrome (FXS), a single gene disorder with an expanded CGG allele on the X chromosome, is the most common form of inherited cognitive impairment. The cognitive deficit ranges from mild learning disabilities to severe intellectual disability. The phenotype includes hyperactivity, short attention span, emotional problems including anxiety, social avoidance, poor eye contact, and hyperarousal to sensory stimuli. Imaging studies in FXS have clarified the impact of the FMR1 mutation on brain development and function by documenting structural abnormalities, predominantly in the caudate nucleus and cerebellum, and functional deficits in the caudate, frontal-striatal circuits, and the limbic system. On the basis of current research results, a targeted treatment for FXS will be available in the near future. Currently, a number of psychopharmacological agents are helpful in treating many of the problems in FXS including hyperactivity, attention deficits, anxiety, episodic aggression, and hyperarousal. Although the targeted treatments aim at strengthening synaptic connections, it is essential that these treatments are combined with learning programs that address the cognitive deficits in FXS. © 2009 Wiley-Liss, Inc. Dev Disabil Res Rev 2009;15:333–342.

Turner syndrome (TS) is a relatively common neurogenetic disorder characterized by complete or partial monosomy-X in a phenotypic female. TS is associated with a cognitive profile that typically includes intact intellectual function and verbal abilities with relative weaknesses in visual–spatial, executive, and social cognitive domains. In this report, we review previous and current research related to the cognitive profile of TS. We also discuss how cognitive impairments in this syndrome may reflect integrative rather than modular deficits. For example, the less commonly reported areas of verbal difficulty in TS and certain visual–spatial deficits seem significantly influenced by impairments in executive function and spatially loaded stimuli. We provide a summary of cognitive testing measures used in the assessment of visual–spatial and executive skills, which includes test domain descriptions as well as a comprehensive examination of social cognitive function in TS. This review concludes with a discussion of ecological interpretations regarding the meaning of cognitive deficits in TS at the individual level. © 2009 Wiley-Liss, Inc. Dev Disabil Res Rev 2009;15:270–278.

Variation in the number of sex chromosomes is a relatively common genetic condition, affecting as many as 1/400 individuals. The sex chromosome aneuploidies (SCAs) are associated with characteristic behavioral and cognitive phenotypes, although the degree to which specific individuals are affected can fall within a wide range. Understanding the effects of different dosages of sex chromosome genes on brain development may help to understand the basis for functional differences in affected individuals. It may also be informative regarding how sex chromosomes contribute to typical sexual differentiation. Studies of 47,XXY males make up the bulk of the current literature of neuroimaging studies in individuals with supernumerary sex chromosomes, with a few small studies or case reports of the other SCAs. Findings in 47,XXY males typically include decreased gray and white matter volumes, with most pronounced effects in the frontal and temporal lobes. Functional studies have shown evidence of decreased lateralization. Although the hypogonadism typically found in 47,XXY males may contribute to the decreased brain volume, the observation that 47,XXX females also show decreased brain volume in the presence of normal pubertal maturation suggests a possible direct dosage effect of X chromosome genes. Additional X chromosomes, such as in 49,XXXXY males, are associated with more markedly decreased brain volume and increased incidence of white matter hyperintensities. The limited data regarding effects of having two Y chromosomes (47,XYY) do not find significant differences in brain volume, although there are some reports of increased head size. Published 2009 by Wiley-Liss, Inc. Dev Disabil Res Rev 2009;15:318–327.

Klinefelter syndrome (47,XXY) was initially described in the context of its endocrinologic and physical features; however, subsequent studies have revealed specific impairments in verbal skills and social functioning. Males with sex chromosomal aneuploidies are known to have variability in their developmental profile with the majority presenting with expressive language deficits. As a consequence of language delays, they have an increased likelihood of language-based learning disabilities and social-emotional problems that may persist through adulthood. Studies on males with 47,XXY have revealed unique behavioral and social profiles with possible vulnerability to autistic traits. The prevalence of males with more than one extra sex chromosome (e.g., 48,XXYY and 48,XXXY) and an additional Y (e.g., 47,XYY) is less common, but it is important to understand their social functioning as it provides insight into treatment implications. © 2009 Wiley-Liss, Inc. Dev Disabil Res Rev 2009;15:328–332.

Since the identification of fetal alcohol syndrome (FAS) over 35 years ago, mounting evidence about the impact of maternal alcohol consumption during pregnancy has prompted increased attention to the link between prenatal alcohol exposure (PAE) and a constellation of developmental disabilities that are characterized by physical, cognitive, and behavioral impairments. These disabilities include a continuum of developmental disorders known as fetal alcohol spectrum disorders (FASDs). Longitudinal studies suggest that individuals with FASDs are at a greatly increased risk for adverse long-term outcomes, including mental health problems and poor social adjustment. This review summarizes the existing literature on mental health outcomes for individuals with PAE across the lifespan, including findings in infancy and early childhood, middle childhood, and adolescence and early adulthood. Research on the psychiatric disabilities suffered by individuals with FASDs throughout development highlights the need for training of mental health professionals in the identification and the provision of specific treatments to address the unique features of this developmental disability since early identification and treatment have been demonstrated to be protective against more serious secondary disabilities. It is hoped that with greater awareness of the mental health problems experienced by individuals with FASDs, these individuals can receive appropriate and early treatment resulting in more adaptive and rewarding lives. © 2009 Wiley-Liss, Inc. Dev Disabil Res Rev 2009;15:225–234.

Animal models of fetal alcohol spectrum disorder (FASD) have been used to demonstrate the specificity of alcohol's teratogenic effects and some of the underlying changes in the central nervous system (CNS) and, more recently, to explore ways to ameliorate the effects of alcohol. The main point of this review is to highlight research findings from the animal literature which point to the impact of the social context or social behavior on the effect(s) of alcohol exposure during development, and also to point to research questions about the social environment and effects of prenatal alcohol exposure that remain to be answered. Alcohol exposure during early development alters maternal responding to the exposed pup in a variety of ways and the alteration in maternal responding could alter later stress responsivity and adult maternal and social behavior of the exposed offspring. Environmental enrichment and voluntary exercise have been shown to ameliorate some of alcohol's impact during development, but the roles of enhanced social interactions in the case of enrichment and of social housing during voluntary exercise need to be more fully delineated. Similarly, the role of social context across the lifespan, such as social housing, social experiences, and contact with siblings, needs further study. Because of findings that alcohol during development alters DNA methylation patterns and that there are alterations in the maternal care of the alcohol-exposed offspring, epigenetic effects and their relationship to social behavior in animal models of FASD are likely to become a fruitful area of research. Because of the simpler social behavior and the short lifespan of rodents, animal models of FASD can be useful in determining how the social context impacts the effects of alcohol exposure during development. © 2009 Wiley-Liss, Inc. Dev Disabil Res Rev 2009;15:200–208.

Historically, alcohol has been used for different purposes including as a part of religious observances, as a food, at times as a medicine and its well-known use as a beverage. Until relatively recently these purposes have not changed and have at times been at odds with one another, resulting in collisions among policies and practices in science, medicine, public policy and the law. One area in which this has been particularly true is that of fetal alcohol spectrum disorders (FASD) where the adverse consequences of consumed alcohol on children in the womb and after birth may have been observed since antiquity, but the actions taken based on such observations have been influenced as much by the socio/cultural/political context of the times in which they were made as by evidence of harm. This article provides an overview of the inherent confusion when new scientific findings confront prevailing medical practice, the history involved in this confusion with respect to FASD, including public policy and legal issues that have arisen around alcohol and pregnancy, and the research and clinical challenges still being faced. Published 2009 Wiley-Liss, Inc. Dev Disabil Res Rev 2009;15:170–175.

Information about “family matters” is vital to developing targeted interventions, reducing placement disruption, and enhancing outcome in fetal alcohol spectrum disorders (FASD). The quality of the caregiving environment and family function are associated with long-term outcome in natural history study of individuals with FASD. This article integrates multiple information sources to better understand the role of family factors in the outcome of individuals with FASD, and how the family is affected by raising a child with this lifelong condition. A brief description of the useful informal literature is brought together with a review of the surprisingly limited body of systematic research findings on FASD and caregiver/family function, and new data describing children with FASD and characteristics of their caregivers. Directions for future data-gathering and intervention development emerge from combining what is already known with an exploration of what can be learned from a highly targeted review of family-related data in the wide-ranging, general literature on developmental disabilities, and use of a proposed conceptual framework that joins a developmental systems perspective with a family systems approach. © 2009 Wiley-Liss, Inc. Dev Disabil Res Rev 2009;15:235–249.

Alcohol use among women of childbearing age is a leading, preventable cause of birth defects and developmental disabilities in the United States. Although most women reduce their alcohol use upon pregnancy recognition, some women report drinking during pregnancy and others may continue to drink prior to realizing they are pregnant. These findings emphasize the need for effective prevention strategies for both pregnant and nonpregnant women who might be at risk for an alcohol-exposed pregnancy (AEP). This report reviews evidence supporting alcohol screening and brief intervention as an effective approach to reducing problem drinking and AEPs that can lead to fetal alcohol spectrum disorders. In addition, this article highlights a recent report of the National Task Force on Fetal Alcohol Syndrome and Fetal Alcohol Effect that describes effective interventions to reduce alcohol use and AEPs, and outlines recommendations on promoting and improving these strategies. Utilizing evidence-based alcohol screening tools and brief counseling for women at risk for an AEP and other effective population-based strategies can help achieve future alcohol-free pregnancies. © 2009 Wiley-Liss, Inc. Dev Disabil Res Rev 2009;15:193–199.