Cognitive and neuropsychological outcomes: more than IQ scores

Improved survival in preterm infants has broadened interest in cognitive and neuropsychological outcomes. The incidence of major disabilities (moderate/severe mental retardation, neurosensory disorders, epilepsy, cerebral palsy) has remained consistent, but high prevalence/low severity dysfunctions (learning disabilities, ADHD, borderline mental retardation, specific neuropsychological deficits, behavioral disorders) have increased. The follow-up literature contains methodologic problems that make generalizations regarding outcome difficult, and these are discussed. Although mean IQs of former VLBW infants generally are in the low average range and are 3-9 points below normal birth weight peers, these scores mask subtle deficits in: visual-motor and visual-perceptual abilities, complex language functions, academics (reading, mathematics, spelling and writing), and attentional skills. There is an increased incidence of non-verbal learning disabilities, need for special educational assistance, and behavioral disorders in children born prematurely. Males have more problems, and there is a trend for worsening outcome over time, due to emergence of more subtle deficits in response to increased performance demands. In addition to IQ and achievement testing in follow-up, there should be evaluation of executive functions and attention, language, sensorimotor functions, visuospatial processes, memory and learning, and behavioral adjustment.     

Infectious and immune factors in the pathogenesis of neurodevelopmental disorders: epidemiology, hypotheses, and animal models

Both genetic and environmental factors contribute to the pathogenesis of a wide variety of neurodevelopmental disorders, including autism, mental retardation, and schizophrenia. Some heritable disorders approach 100% penetrance; nonetheless, even in these disorders, subtle aspects of clinical disease expression may be influenced by the environment. In other disorders with genetic influences, exogenous factors, and the timepoint(s) during nervous system development at which they are introduced, modulate expression of disease. Elucidation of the mechanisms guiding this intricate interplay between host response genes, environmental agents, and the neurodevelopmental context within which these interactions occur, is necessary to understand the continuum of clinical outcomes. This chapter will review the evidence that infectious and immune factors may contribute to the pathogenesis of neurodevelopmental disorders, describe an animal model of neurodevelopmental disorders based upon viral infection, identify processes by which neural circuitry may be compromised, and outline areas for future research.     

Identifying operant functions for tics in children with mental retardation

Functional analyses were used to assess the effects of environmental consequences on occurrences of repetitive vocal behavior that had been diagnosed as chronic vocal tics in two adolescent males with mental retardation. The functional analyses indicated that one participant's tics were sensitive to positive reinforcement in the form of caregiver attention, while the second participant's tics occurred independent of social consequences. The results are discussed in terms of using functional analysis methodology during assessment, diagnosis, and treatment selection for suspected tics. Copyright © 2002 John Wiley & Sons, Ltd.     

Could stress cause psychosis in individuals vulnerable to schizophrenia?

It has long been considered that psychosocial stress plays a role in the expression of symptoms in schizophrenia (SZ), as it interacts with latent neural vulnerability that stems from genetic liability and early environmental insult. Advances in the understanding of the neurobiology of the stress cascade in both animal and human studies lead to a plausible model by which this interaction may occur: through neurotoxic effects on the hippocampus that may involve synaptic remodeling. Of late, the neurodevelopmental model of SZ etiology has been favored. But an elaboration of this schema that credits the impact of postnatal events and considers a role for neurodegenerative changes may be more plausible, given the evidence for gene-environment interaction in SZ expression and progressive structural changes observed with magnetic resonance imaging. Furthermore, new insights into nongliotic neurotoxic effects such as apoptosis, failure of neurogenesis, and changes in circuitry lead to an expansion of the time frame in which environmental effects may mediate expression of SZ symptoms.     

Effects of the iodine deficiency on intellectual variables among children

An association between severe iodine deficiency and poor mental development has been found in many studies. We examined the relationship between moderate or mild iodine deficiency and intellectual capacity in order to determine whether problems common to severe iodine deficiency (including mental retardation) also emerge in a more subtle form. We also wished to know whether the classic methodology (comparing iodine-deficient zones with nondeficient zones) is the most adequate, and propose to combine this grouping by zones with urinary iodine presented by individuals in each zone. We measured IQ, manipulative and verbal capacity, attention, visual motor ability and disruptive behaviour, variables that have barely been studied in this kind of investigations. The sample comprised 760 schoolchildren from the province of Jaén (southern Spain). Our results show that children with low levels of iodine intake and with urinary iodine concentration lower than 100 microg/litre had a lower IQ and displayed more disruptive behaviour than children with high levels of the criteria. The other variables were not associated with iodine deficiency.     

新生儿癫痫与脑发育的关系

患有癫痈的新生儿在成年期癫痫发作、智能障碍和行为问题的发生率明显增高。新生儿癫痈远期危害的确切机制尚不明确。癫痫发作对成熟脑和发育脑的影响具有差异性,新生儿期癫痈发作可能通过干扰脑的正常发育,引起神经系统发育障碍。本文对新生儿癫痫与脑发育研究中亟待解决的问题作一初步探讨。     

Developmental psychology and mental retardation. Integrating scientific principles with treatment practices

The current debates about "best practices" within mental retardation reflect key unresolved issues about the nature of mental retardation and the goals of treatment programs. The central axiom proposed is that better integration of basic principles about human development with treatment practices for children will yield substantial benefits to individuals and society. To illustrate the format for this proposed integration, three principles have been abstracted from scientific inquiry in human development: (a) targeted environmental prevention, (b) metacognitive conveyance, and (c) ecological dominion. A contextual analysis, using special education as an example of a major treatment setting, indicates that application of these developmental principles is likely to reduce the prevalence of mild retardation (as currently defined), to minimize social and behavioral problems, and to foster improved levels of environmental mastery (adaptive success) for many children with low IQs and cognitive deficiencies. Consistent with these developmental principles, the current construct of mental retardation is judged inadequate, and an alternative diagnostic strategy is proposed. This strategy is based on repeated developmental profiling of a child and his or her biosocial environmental history.     

The use of genomic microarrays to study chromosomal abnormalities in mental retardation

Mental retardation affects 2 to 3% of the US population. It is defined by broad criteria, including significantly subaverage intelligence, onset by age 18, and impaired function in a group of adaptive skills. A myriad of genetic and environmental causes have been described, but for approximately half of individuals diagnosed with mental retardation the molecular basis remains unknown. Genomic microarrays, also called array comparative genomic hybridization (array CGH), represent one of several novel technologies that allow the detection of chromosomal abnormalities, such as microdeletions and microduplications, in a rapid, high throughput fashion from genomic DNA samples. In one early application of this technology, genomic microarrays have been used to characterize the extent of chromosomal changes in a group of patients diagnosed with one particular type of disorder that causes mental retardation, such as deletion 1p36 syndrome. In another application, DNA samples from individuals with idiopathic mental retardation have been assayed to scan the entire genome in attempts to identify chromosomal changes. Genomic microarrays offer both a genome-wide perspective of chromosomal aberrations as well as higher resolution (to the level of approximately one megabase) compared to alternative available technologies.     

Prenatal tobacco exposure: developmental outcomes in the neonatal period

Smoking during pregnancy is a persistent public health problem that has been linked to later adverse outcomes. The neonatal period--the first month of life--carries substantial developmental change in regulatory skills and is the period when tobacco metabolites are cleared physiologically. Studies to date mostly have used cross-sectional designs that limit characterizing potential impacts of prenatal tobacco exposure on the development of key self-regulatory processes and cannot disentangle short-term withdrawal effects from residual exposure-related impacts. In this study, pregnant participants (N = 304) were recruited prospectively during pregnancy, and smoking was measured at multiple time points, with both self-report and biochemical measures. Neonatal attention, irritable reactivity, and stress dysregulation were examined longitudinally at three time points during the first month of life, and physical growth indices were measured at birth. Tobacco-exposed infants showed significantly poorer attention skills after birth, and the magnitude of the difference between exposed and nonexposed groups attenuated across the neonatal period. In contrast, exposure-related differences in irritable reactivity largely were not evident across the 1st month of life, differing marginally at 4 weeks of age only. Third-trimester smoking was associated with pervasive, deleterious, dose–response impacts on physical growth measured at birth, whereas nearly all smoking indicators throughout pregnancy predicted level and growth rates of early attention. The observed neonatal pattern is consistent with the neurobiology of tobacco on the developing nervous system and fits with developmental vulnerabilities observed later in life.     

The Relationship of Functional Variables and Psychopathology to Aggressive Behavior in Persons With Severe and Profound Mental Retardation

A number of hypotheses have emerged regarding the etiology of physical aggression in persons with mental retardation. Although a multicomponent model is appropriate, results of functional analysis-based studies have yielded promising results in identifying instigating and maintaining factors of aggression. However, the relationship between functional variables and conditions such as psychiatric diagnosis to aggressive behavior has yet to be investigated in persons with mental retardation. We conducted a study examining the prevalence of environmental or physical factors in aggressive behavior in mentally retarded persons with and without psychiatric disturbance. One hundred and thirty-five individuals with mental retardation who exhibited physical aggression were assessed with the Questions About Behavior Function Scale (QABF) to identify environmental or physical contribution to aggressive behavior. One or more behavioral functions were identified for 75% of the participants. Additionally, of 66 of the participants scoring above the clinical cutoff on an assessment for dual diagnosis, 75% met criteria for an environmental or physical function for aggression. No significant differences in number of participants with an identifiable function of aggression were found between the no dual diagnosis and dual diagnosis groups. Our findings underscore the importance of identifying functions underlying aggressive behavior in persons with mental retardation, and the need to consider functional variables regardless of psychiatric condition in treatment planning efforts for such individuals.     

Identifying environmental contributions to autism: provocative clues and false leads

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.     

A geography of contaminated sites,mental health and wellbeing: The body,home, environment and state at Australian PFAS sites

Health geographers have long been interested in the connection between place and mental health, proposing that settings influence mental health and vice versa. Research on environmental contamination has tended to focus on the former part of this relationship, examining how the mental health and wellbeing of residents living nearby are affected by the contamination. There has been little investigation of the latter component: how mental health and wellbeing may shape place. This article seeks to explore how the mental health and wellbeing of residents living on or near environmental contamination may be both affected by and reproduced in place. It considers this in a case study of per- and poly-fluoroalkyl substances (PFAS) contamination in New South Wales, Australia, by drawing on interviews with residents. Focus is placed on examining how residents report psychological distress associated with the contamination and how this distress may permeate beyond the contaminated site to become enmeshed in other places at different scales, such as the body, home, local environment, and state. Ultimately, it is proposed that these places reproduce distress on their own and require just as much attention in addressing adverse psychological effects as the physical contamination itself.     

The prevalence of mental retardation: Cross-cultural considerations from Sweden and the United States

Recent reports from Sweden and other European countries have shown a sharp disparity between their incidence and prevalence figures on mild mental retardation and similar figures in the U.S. (Grunewald, 1979; Martin, Blodgett, Edwards, Geer, & Melcher, 1974; Robinson & Robinson, 1976).The purpose of this paper is to provide a model of intellectual performance that might explain such disparities and predict future levels of occurrence of mild mental retardation. Such explanations should have relevance for our views on the development of intellectual ability as well as, on a practical level, planning the allocation of treatment resources. Such planning clearly depends upon the number of children having the condition in question.Over the past few decades we have progressed substantially in our ability to describe mental retardation and to differentiate it from conditions that superficially resemble it; such as, autism, learning disabilities, schizophrenia, etc., (Baroff, 1974; Robinson & Robinson, 1976). Our ability to identify variables that relate to mild mental retardation also has developed substantially, but correlation does not necessarily lead to understanding. One of the large set of variables that often is associated with mild mental retardation in the U.S. is poverty. But “poverty” is too broad a variable to be explanatory. Such a dimension is a surrogate factor standing in the place of other variables, not yet understood, that control, in part, the actual process, by which the child develops the condition of mild mental retardation (Kirk & Gallagher, 1983). A series of papers has been presented by psychologists in Sweden that allow us to address this issue.The ability to observe two cultures, Sweden and the U.S., that have both substantial similarities and differences provides a natural comparison of the prevalence of mental retardation that would be impossible to achieve through experimental manipulation. Prevalence is used here as the total number of cases present in a population group during a specific interval of time (Kramer, 1975).     

Lead-induced impairments in complex cognitive function: offerings from experimental studies.

Experimental studies, relying primarily on rodent and non-human primate models, have produced compelling evidence supporting effects of chronic low level lead exposure on learning, with the magnitude of those effects possibly modulated by developmental period of exposure and learning paradigm parameters. In contrast, changes in memory are not systematically demonstrated. The impact of lead exposure on attention has yet to be clearly delineated in either human or experimental studies, although impulsivity or aversion to delay appears to be a sensitive component of attention that may be targeted.     

恢复性环境研究:理论、方法与进展

近十年来,"恢复性环境"成为环境心理学研究的热点。目前,从恢复结果的角度,注意恢复理论和心理进化理论认为,恢复性环境是指有助于人们更好地从心理疲劳以及和压力相伴随的消极情绪、生理反应中恢复过来的环境。对该环境的研究主要采用量表法和实验法,研究结果涉及恢复结果、影响恢复的因素、恢复和偏好的关系、恢复性环境的眼动特征以及临床应用。今后应该更侧重对恢复性环境理论和研究设计的进一步完善、量表的效度验证,并加强研究成果的具体应用。     

Measuring behavior in genetic disorders of mental retardation

As researchers have examined the so-called "behavioral phenotypes" of different genetic mental retardation conditions, the measurement of behavior becomes increasingly important. From earlier, more global examinations of noteworthy behaviors or profiles, recent researchers have moved from reliance on a single, all-encompassing questionnaire to more multimethod, multireporter approaches. This paper summarizes strengths and weaknesses in utilizing parent-report questionnaires and checklists; psychiatric nosology and specific psychiatric questionnaires; observational studies; reports from individuals with mental retardation themselves; profile analyses of psychometric test and subtest scores; and "grouping" analyses of items (factor analysis) and people (cluster analysis). Although we advocate a mixture of approaches to behavioral assessment, in future work researchers will require more theoretically driven methods for studying behavior, greater acknowledgment that the child's behavior is simply one event in ongoing interactions-transactions with other people, and more attention to age-related changes in behavioral phenotypes.     

空气污染的不良效应及理论模型:环境心理学的视角

空气污染的不良效应不仅限于生理健康损害,还涉及认知功能、情绪和行为等多方面的消极影响。针对空气污染不良效应的形成机制,以往研究提出了环境应激模型和社会-环境交互模型,这些理论模型强调空气污染的不良效应不仅涉及污染的直接暴露程度,也取决于个体的身心状况以及他对空气污染的主观评价。基于以往研究的不足,尤其是环境心理学介入空气污染研究的可行性,未来研究可着眼于改进空气污染的心理学研究方法,开展空气污染的环境应激和风险感知研究。     

Service in the Gulf War and Significant Health Problems: Focus on the Central Nervous System

The consensus of several studies on health among Gulf War (GW)-deployed veterans is that they have elevated symptom complaints. Central nervous system (CNS) symptoms among these veterans have been assessed in several investigations. Studies have disagreed as to whether there are neuropsychological deficits in GW-deployed veterans relative to controls. When differences between these groups have been found, they have often been attributed to stress or psychiatric factors, although exposures to neurotoxic substances present in the GW theatre have also been indicted as possible explanations. A review of the existing literature as well as the 5 papers contained in this issue of Journal of Psychopathology and Behavioral Assessment suggests that the neuropsychological and health symptom sequelae of GW zone service are multidetermined and cannot easily be explained on the basis of simplistic models of causation. Psychological, historical, and exposure parameters must be considered in the scientific evaluation of this problem.     

Prenatal cigarette exposure and infant learning stimulation as predictors of cognitive control in childhood

Prenatal exposures to neurotoxins and postnatal parenting practices have been shown to independently predict variations in the cognitive development and emotional-behavioral well-being of infants and children. We examined the independent contributions of prenatal cigarette exposure and infant learning stimulation, as well as their inter-relationships in predicting variations in the proficiency of executive attention, a core element of cognitive control and self-regulation. Participants were an ethnic-racially, socio-economically diverse sample of 249 children followed from birth in the Project on Human Development in Chicago Neighborhoods. We obtained histories of prenatal exposure to alcohol, cigarettes, and other drugs, and we assessed socio-economic status and learning stimulation during a home visit when the participants were infants. In childhood we utilized the Attention Networks Test to assess the proficiency of executive attention during two home visits, one year apart. Accounting for age, SES, prenatal alcohol exposure, and baseline performance, we found that prenatal cigarette exposure impaired the speed of executive attention. Infant learning stimulation mitigated these effects, and predicted better accuracy of executive attention as well, suggestive of both protective and health promoting effects. Effect sizes for these relations, whether examined independently or by their inter-relationships, were comparable to if not greater in magnitude than the effects of age on speed and accuracy, highlighting the importance of these very early experiences in shaping the proficiency of self-regulation. Since executive attention is central to cognitive control and self-regulation, previously described relations between prenatal cigarette exposure, parenting practices, and some forms of childhood psychopathology may be contingent on how early learning stimulation contributes to the proficiency of executive attention through direct and indirect effects. Furthermore, considering the prolonged developmental trajectory of executive attention, interventions to support provision of learning stimulation may mitigate poor outcomes for some at-risk children by promoting development of more proficient executive attention.