Ment Retard Dev Disabil Res Rev
· 2005 · PMID 15856438
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The development of feeding and swallowing is the result of a complex interface between the developing nervous system, various physiological systems, and the environment. The purpose of this article is to review the neuro...The development of feeding and swallowing is the result of a complex interface between the developing nervous system, various physiological systems, and the environment. The purpose of this article is to review the neurobiology, development, and assessment of feeding and swallowing during early infancy. In recent years, there have been exciting advances in our understanding of the physiology and neurological control of feeding and swallowing. These advances may prove useful in furthering our understanding of the pathophysiology of dysphagia in infancy. Progress in developing standardized, reliable, and valid measures of oral sensorimotor and swallowing function in infancy has been slow. However, there have been significant advances in the instrumental analysis of feeding and swallowing disorders in infancy, including manometric analyses of sucking and swallowing, measures of respiration during feeding, videofluoroscopic swallow evaluations, ultrasonography, and flexible endoscopic examination of swallowing. Further efforts are needed to develop clinical evaluative measures of dysphagia in infancy.
Ment Retard Dev Disabil Res Rev
· 2005 · PMID 15856437
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During the twentieth century, study of the neurologic development of the fetus and infant has resulted in multiple neurodevelopmental assessments. They have been used both for determination of the integrity of the neonat...During the twentieth century, study of the neurologic development of the fetus and infant has resulted in multiple neurodevelopmental assessments. They have been used both for determination of the integrity of the neonate as well as for assessment of the child's outcome from prenatal and neonatal medical interventions. These models of assessment have broadened our view and understanding of the development of functions such as movement, posture, attention, oromotor skills, and behavior. The link between these areas and the traditional areas of neurologic and psychiatric examination of older children and adults is explored through discussion of the maturation of movement, cranial nerve function, sensory, cognitive, and behavioral responses. Gaps in knowledge remain about the relationship between early neurodevelopmental assessments and later findings. A single unified means of examining the infant is also lacking.
Ment Retard Dev Disabil Res Rev
· 2005 · PMID 15856436
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The Assessment of Preterm Infants' Behavior (APIB) is a newborn neurobehavioral assessment appropriate for preterm, at risk, and full-term newborns, from birth to 1 month after expected due date. The APIB is based in eth...The Assessment of Preterm Infants' Behavior (APIB) is a newborn neurobehavioral assessment appropriate for preterm, at risk, and full-term newborns, from birth to 1 month after expected due date. The APIB is based in ethological-evolutionary thought and focuses on the assessment of mutually interacting behavioral subsystems in simultaneous interaction with the environment. The subsystems of functioning assessed include the autonomic (respiration, digestion, color), motor (tone, movement, postures), state organization (range, robustness, transition patterns), attention (robustness, transitions), and self-regulation (effort, success) systems as well as the degree of facilitation required to support reorganization and subsystem balance. The environment is represented by a sequence of distal, proximal, tactile, and vestibular challenges, derived from the BNBAS. The APIB conceptualizes infant competence as the degree of differentiation of subsystem function and degree of modulation of subsystem balance at any stage in infant development. Infants are understood as actively seeking their next differentiation, while counting on good enough environments to assure progressing developmental competence. In the case of interference such as premature birth, the mismatch of expectation and actual experience causes misalignment, which may become developmentally costly. The assessment is a finely tuned dialogue between examiner and infant, which requires training, skill and self-knowledge. The APIB has well established inter-rater-reliability, concurrent and construct validity, and is clinically relevant for behavioral intervention and individually appropriate and supportive care.
Ment Retard Dev Disabil Res Rev
· 2004 · PMID 15666342
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Autism is a heritable disorder characterized by phenotypic and genetic complexity. This review begins by surveying current linkage, gene association, and cytogenetic studies performed with the goal of identifying autism...Autism is a heritable disorder characterized by phenotypic and genetic complexity. This review begins by surveying current linkage, gene association, and cytogenetic studies performed with the goal of identifying autism disease susceptibility variants. Though numerous linkages and associations have been identified, they tend to diminish upon closer examination or attempted replication. The review therefore explores challenges to current methodologies presented by the complexities of autism that might underlie some of the current difficulties, and finishes by describing emerging phenotypic, statistical, and molecular investigational approaches that offer hope of overcoming those challenges.
Seltzer MM, Shattuck P, Abbeduto L
… +1 more, Greenberg JS
Ment Retard Dev Disabil Res Rev
· 2004 · PMID 15666341
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This article seeks to elucidate the trajectory of development in adolescents and adults with autism. Prospective, retrospective, and cross-sectional studies are reviewed to reveal the manifestation of and changes in the...This article seeks to elucidate the trajectory of development in adolescents and adults with autism. Prospective, retrospective, and cross-sectional studies are reviewed to reveal the manifestation of and changes in the core symptoms of autism in adolescence and adulthood. Comparing children with adolescents and adults, modest degrees of symptom abatement and improvement in skills have been documented in multiple studies, as are increases in verbal and decreases in performance IQ. Nevertheless, most individuals do not attain normative outcomes in adulthood and continue to manifest significant degrees of symptomatology and dependency. However, a small sub-group (about 15%) has more favorable adult outcomes.
Ment Retard Dev Disabil Res Rev
· 2004 · PMID 15666340
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A wide variety of nonestablished treatments have been proposed as "cures" for the core features of autism and are used frequently despite having largely escaped scientific scrutiny. In contrast, a growing body of empiric...A wide variety of nonestablished treatments have been proposed as "cures" for the core features of autism and are used frequently despite having largely escaped scientific scrutiny. In contrast, a growing body of empirical evidence supports the use of a few forms of theory-based and empirically validated treatment for some aspects of the core features of autism. These include behavioral/psychoeducational interventions and specific forms of medication treatment, which can produce significant improvements in communication, social interaction, and problem behaviors that both maintain over time and generalize across settings. While there is no doubt that treatment and educational services for persons with autism have improved over the past 6 decades, it also appears that significant issues remain with respect to (1) the routine application of validated treatments for the majority of cases with autism, (2) the resistance to even validated forms of treatment for a substantial minority of cases with autism, and (3) the extent to which validated treatments effectively treat the specific core features of autism that are most disabling for persons with autism and their families.
Lawler CP, Croen LA, Grether JK
… +1 more, Van de Water J
Ment Retard Dev Disabil Res Rev
· 2004 · PMID 15666339
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The potential role of environmental factors in autism spectrum disorders (ASD) is an area of emerging interest within the public and scientific communities. The high degree of heritability of ASD suggests that environmen...The potential role of environmental factors in autism spectrum disorders (ASD) is an area of emerging interest within the public and scientific communities. The high degree of heritability of ASD suggests that environmental influences are likely to operate through their interaction with genetic susceptibility during vulnerable periods of development. Evaluation of the plausibility of specific neurotoxicants as etiological agents in ASD should be guided by toxicological principles, including dose-effect dependency and pharmacokinetic parameters. Clinical and epidemiological investigations require the use of sufficiently powered study designs with appropriate control groups and unbiased case ascertainment and exposure assessment. Although much of the existing data that have been used to implicate environmental agents in ASD are limited by methodological shortcomings, a number of efforts are underway that will allow more rigorous evaluation of the role of environmental exposures in the etiology and/or phenotypic expression of the disorder. Surveillance systems are now in place that will provide reliable prevalence estimates going forward in time. Anticipated discoveries in genetics, brain pathology, and the molecular/cellular basis of functional impairment in ASD are likely to provide new opportunities to explore environmental aspects of this disorder.
Ment Retard Dev Disabil Res Rev
· 2004 · PMID 15666338
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The goal of this review of the research literature is to discuss approaches to the early detection of autism in infancy. Early detection would enable diagnoses to be made before 18 months of age rather than at 24-30 mont...The goal of this review of the research literature is to discuss approaches to the early detection of autism in infancy. Early detection would enable diagnoses to be made before 18 months of age rather than at 24-30 months, the age where diagnoses start to be made now. After summarizing the criteria for a deficit to be considered "core" to the disorder, the literature on research strategies used in early detection is examined. In order to guide the design of future studies, the review then turns to an overview of what is known about the processes of early social development in typically developing children that underlie the domains in which core deficits are manifested in young children with autism. The social domains covered in the review are those that show development in typically developing infants below 18 months of age: dyadic interaction and imitation; emotion discrimination; and attachment. The review concludes that all of these areas are worthy of investigation in young children, particularly those at higher risk of showing some of the core deficits of autism such as the infant siblings of children with autism.
Ment Retard Dev Disabil Res Rev
· 2004 · PMID 15666336
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In this review article, we summarize recent progress toward understanding the neural structures and circuitry underlying dysfunctional social cognition in autism. We review selected studies from the growing literature th...In this review article, we summarize recent progress toward understanding the neural structures and circuitry underlying dysfunctional social cognition in autism. We review selected studies from the growing literature that has used the functional neuroimaging techniques of cognitive neuroscience to map out the neuroanatomical substrates of social cognition in autism. We also draw upon functional neuroimaging studies with neurologically normal individuals and individuals with brain lesions to highlight the insights these studies offer that may help elucidate the search for the neural basis of social cognition deficits in autism. We organize this review around key brain structures that have been implicated in the social cognition deficits in autism: (1) the amygdala, (2) the superior temporal sulcus region, and (3) the fusiform gyrus. We review some of what is known about the contribution of each structure to social cognition and then review autism studies that implicate that particular structure. We conclude with a discussion of several potential future directions in the cognitive neuroscience of social deficits in autism.
Ment Retard Dev Disabil Res Rev
· 2004 · PMID 15666335
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The importance of genetic factors in autism has prompted the development of mutant mouse models to advance our understanding of biological mechanisms underlying autistic behaviors. Mouse models of human neuropsychiatric...The importance of genetic factors in autism has prompted the development of mutant mouse models to advance our understanding of biological mechanisms underlying autistic behaviors. Mouse models of human neuropsychiatric diseases are designed to optimize (1) face validity, i.e., resemblance to the human symptoms; (2) construct validity, i.e., similarity to the underlying causes of the disease; and (3) predictive validity, i.e., expected responses to treatments that are effective in the human disease. There is a growing need for mouse behavioral tasks with all three types of validity for modeling the symptoms of autism. We are in the process of designing a set of tasks with face validity for the defining features of autism: deficits in appropriate reciprocal social interactions, deficits in verbal social communication, and high levels of ritualistic repetitive behaviors. Social approach is tested in an automated three-chambered apparatus that offers the subject a choice between a familiar environment, a novel environment, and a novel environment containing a stranger mouse. Preference for social novelty is tested in the same apparatus, with a choice between the start chamber, the chamber containing a familiar mouse, and the chamber containing a stranger mouse. Social communication is evaluated by measuring the ultrasonic distress vocalizations emitted by infant mouse pups and the parental response of retrieving the pup to the nest. Resistance to change in ritualistic repetitive behaviors is modeled by forcing a change in habit, including reversal of the spatial location of a reinforcer in a T-maze task and in the Morris water maze. Mouse behavioral tasks that may model additional features of autism are discussed, including tasks relevant to anxiety, seizures, sleep disturbances, and sensory hypersensitivity. Applications of these tests include (1) behavioral phenotyping of transgenic and knockout mice with mutations in genes relevant to autism, (2) characterization of mutant mice derived from random chemical mutagenesis, (3) DNA microarray analyses of genes in inbred strains of mice that differ in social interaction, social communication and resistance to change in habit, and (4) evaluation of proposed therapeutics for the treatment of autism.
Ment Retard Dev Disabil Res Rev
· 2004 · PMID 15666334
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Autism is a complex, behaviorally defined, developmental brain disorder with an estimated prevalence of 1 in 1,000. It is now clear that autism is not a disease, but a syndrome with a strong genetic component. The etiolo...Autism is a complex, behaviorally defined, developmental brain disorder with an estimated prevalence of 1 in 1,000. It is now clear that autism is not a disease, but a syndrome with a strong genetic component. The etiology of autism is poorly defined both at the cellular and the molecular levels. Based on the fact that seizure activity is frequently associated with autism and that abnormal evoked potentials have been observed in autistic individuals in response to tasks that require attention, several investigators have recently proposed that autism might be caused by an imbalance between excitation and inhibition in key neural systems including the cortex. Despite considerable ongoing effort toward the identification of chromosome regions affected in autism and the characterization of many potential gene candidates, only a few genes have been reproducibly shown to display specific mutations that segregate with autism, likely because of the complex polygenic nature of this syndrome. Among those, several candidate genes have been shown to control the early patterning and/or the late synaptic maturation of specific neuronal subpopulations controlling the balance between excitation and inhibition in the developing cortex and cerebellum. In the present article, we review our current understanding of the developmental mechanisms patterning the balance between excitation and inhibition in the context of the neurobiology of autism.
Ment Retard Dev Disabil Res Rev
· 2004 · PMID 15666333
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New insights into biological factors that underlie autism may be gained by comparing autism to other neurodevelopmental disorders that have autistic features and relatively well-delineated genetic etiologies or neurobiol...New insights into biological factors that underlie autism may be gained by comparing autism to other neurodevelopmental disorders that have autistic features and relatively well-delineated genetic etiologies or neurobiological findings. This review moves beyond global diagnoses of autism and instead uses an endophenotypic approach to compare specific clusters of autistic symptomatology to features of chromosome 15q11-q13 disorders. Paternally or maternally derived deficiencies of 15q11-q13 result in Prader-Willi or Angelman syndromes, and we first use a global approach to review potential autism susceptibility genes in the 15q11-q13 region. We then use a more trait-based approach to suggest possible ties between specific phenotypic characteristics of autism and Prader-Willi syndrome, namely savant-like skills. We conclude with insights from pathophysiological studies that implicate altered development of specific neuron types and circuits in the cerebral cortex as part of the pathophysiological processes associated with autism and mental retardation.
Ment Retard Dev Disabil Res Rev
· 2004 · PMID 15611989
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Children with developmental speech/language impairments are at higher risk for reading disability than typical peers with no history of speech/language impairment. This article reviews the literacy outcomes of children w...Children with developmental speech/language impairments are at higher risk for reading disability than typical peers with no history of speech/language impairment. This article reviews the literacy outcomes of children with speech/language impairments, clarifying the differential risk for three groups of children: speech production impairments alone, oral language impairments alone, and speech production and oral language impairments. Children at greatest risk for reading and writing disabilities are children with language impairments alone and children with comorbid speech impairments and language impairments. For children with speech impairments alone, there is limited risk for literacy difficulties. However, even when reading skills are within the average range, children with speech impairments may have difficulties in spelling. Children with language impairments are likely to display reading deficits in word decoding and reading comprehension. It is not clear what role early literacy interventions play in the amelioration of reading difficulties in these populations.
Ment Retard Dev Disabil Res Rev
· 2004 · PMID 15611988
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Preverbal communication and joint attention have long been of interest to researchers and practitioners. Both attending to social partners and sharing attentional focus between objects or events and others precede the on...Preverbal communication and joint attention have long been of interest to researchers and practitioners. Both attending to social partners and sharing attentional focus between objects or events and others precede the onset of a child's first lexicon. In addition, these prelinguistic acts also appear to have important implications with regard to learning to socialize. The construct of joint attention has been noted as an early developing area prior to the transition to symbolic communication. Thus, the importance of joint attention in typically developing children, and the lack thereof in children with autism, has interested researchers for use in diagnosis and intervention for autism. That is, joint attention has been gaining momentum as an area that not only helps characterize children with autism, but also as a prognostic indicator and a potential intervention goal. In this paper, the status of the literature about initiation of joint attention by young typically developing children and young children with autism was examined. Empirical studies regarding joint attention behaviors, including eye gaze alternation, the use of protodeclaratives and protoimperatives, and studies that investigated joint attention as a predictor of language acquisition were reviewed. Possible areas for future research for children with autism are discussed.
Ment Retard Dev Disabil Res Rev
· 2004 · PMID 15611987
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The purpose of this review is to discuss the importance of treatment efficacy research in language comprehension in MR/DD populations. Although receptive language deficit is an integral part of most MR/DD typologies, the...The purpose of this review is to discuss the importance of treatment efficacy research in language comprehension in MR/DD populations. Although receptive language deficit is an integral part of most MR/DD typologies, there have been relatively few studies evaluating the effectiveness or efficacy of treatment for this condition. Recently, there has been increased attention placed on auditory processing in children with disabilities, an aspect of cognition related to receptive language, but there have also been few studies investigating the effectiveness or efficacy of training designed to improve auditory processing. In addition to arguing that additional studies in this area are needed, the review includes several theoretical frameworks for addressing the treatment of receptive language deficits in MR/DD.
Ment Retard Dev Disabil Res Rev
· 2004 · PMID 15611986
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In this article, we consider the theoretical debates and frameworks that have shaped research on language development and intervention in persons with mental retardation over the past four decades. Our starting point is...In this article, we consider the theoretical debates and frameworks that have shaped research on language development and intervention in persons with mental retardation over the past four decades. Our starting point is the nativist theory, which has been espoused most forcefully by Chomsky. We also consider more recent alternatives to the nativist approach, including the social-interactionist and emergentist approaches, which have been developed largely within the field of child language research. We also consider the implications for language development and intervention of the genetic syndrome-based approach to behavioral research advocated by Dykens and others. We briefly review the impact and status of the debates spurred by the nativist approach in research on the course of language development in individuals with mental retardation. In addition, we characterize some of the achievements in language intervention that have been made possible by the debates spurred by nativism and the various alternatives to it. The evidence we consider provides support for all three alternatives to the nativist approach. Moreover, successful interventions appear to embody elements of several of these approaches as well as other theoretical approaches (e.g., behaviorism). We conclude that language intervention must be theoretically eclectic in its approach, with different strategies appropriate for teaching different features of language, at different points in development, and for children displaying different characteristics or learning histories.
Ment Retard Dev Disabil Res Rev
· 2004 · PMID 15611985
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This article provides a rationale for considering predictors of growth in a treatment group as inadequate to identifying predictors of treatment response. When we interpret predictors of growth in a treatment group as sy...This article provides a rationale for considering predictors of growth in a treatment group as inadequate to identifying predictors of treatment response. When we interpret predictors of growth in a treatment group as synonymous with predictors of treatment response, we implicitly attribute all of the treated children's growth to the treatment, an untenable assumption under most conditions. We also contend that the use of standard scores in predictors of growth studies does not allow us to differentiate growth from treatment, from growth from other factors. We present two research methodologies that are appropriate methods of identifying predictors of treatment response: (a) single-subject experimental logic utilized to identify the specific participants in which treatment responses (not just growth) were found, combined with follow-up group comparison logic to identify the characteristics on which responders and nonresponders differ, and (b) statistical interactions among child/family/context characteristics and randomly assigned group membership. Principles for selecting potential predictors of treatment response are provided.
Ment Retard Dev Disabil Res Rev
· 2004 · PMID 15611984
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This issue of MRDD research reviews is dedicated to treatment efficacy research. The treatment of MRDD conditions has long been a central question, but the clinical science of treatment efficacy has not yet been systemat...This issue of MRDD research reviews is dedicated to treatment efficacy research. The treatment of MRDD conditions has long been a central question, but the clinical science of treatment efficacy has not yet been systematically applied to many MRDD typologies. The purpose of this paper is to provide an overview of this special issue and to provide a rationale for including treatment efficacy research as a tool for studying selected neurological development and genetic correlates of MRDD. Existing treatment efficacy paradigms should be applied systematically to relevant populations (and theoretical questions) and new, objectively tested paradigms should be developed in order to integrate ongoing discovery in MRDD.
Ment Retard Dev Disabil Res Rev
· 2004 · PMID 15611983
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The purpose of this review is to provide a model for studying genetic association of response to intervention in child language disorders. In addition to a theoretical overview and review of different approaches to study...The purpose of this review is to provide a model for studying genetic association of response to intervention in child language disorders. In addition to a theoretical overview and review of different approaches to studying candidate genes, a specific methodology for completing this type of analysis is presented. The goal of the analysis is to provide detail beyond simple broad phenotyping for affected and nonaffected individuals and to take advantage of data yielded from concise behavioral phenotyping often available in treatment studies.