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Atypical Development (atypical + development)

Distribution by Scientific Domains
Psychology75%

Selected Abstracts

Developmental profiles for multiple object tracking and spatial memory: typically developing preschoolers and people with Williams syndrome

DEVELOPMENTAL SCIENCE, Issue 3 2010
Kirsten O'Hearn
The ability to track moving objects, a crucial skill for mature performance on everyday spatial tasks, has been hypothesized to require a specialized mechanism that may be available in infancy (i.e. indexes). Consistent with the idea of specialization, our previous work showed that object tracking was more impaired than a matched spatial memory task in individuals with Williams syndrome (WS), a genetic disorder characterized by severe visuo-spatial impairment. We now ask whether this unusual pattern of performance is a reflection of general immaturity or of true abnormality, possibly reflecting the atypical brain development in WS. To examine these two possibilities, we tested typically developing 3- and 4-year-olds and people with WS on multiple object tracking (MOT) and memory for static spatial location. The maximum number of objects that could be correctly tracked or remembered (estimated from the k -statistic) showed similar developmental profiles in typically developing 3- and 4-year-old children, but the WS profile differed from either age group. People with WS could track more objects than 3-year-olds, and the same number as 4-year-olds, but they could remember the locations of more static objects than both 3- and 4-year-olds. Combining these data with those from our previous studies, we found that typically developing children show increases in the number of objects they can track or remember between the ages of 3 and 6, and these increases grow in parallel across the two tasks. In contrast, object tracking in older children and adults with WS remains at the level of 4-year-olds, whereas the ability to remember multiple locations of static objects develops further. As a whole, the evidence suggests that MOT and memory for static location develop in tandem typically, but not in WS. Atypical development of the parietal lobe in people with WS could play a causal role in the abnormal, uneven pattern of performance in WS. This interpretation is consistent with the idea that multiple object tracking engages different mechanisms from those involved in memory for static object location, and that the former can be particularly disrupted by atypical development. [source]

PRECLINICAL STUDY: Atypical development of behavioural sensitization to 3,4-methylenedioxymethamphetamine (MDMA, ,Ecstasy') in adolescent rats and its expression in adulthood: role of the MDMA chirality

ADDICTION BIOLOGY, Issue 1 2010
Nora Von Ameln
ABSTRACT Despite the great popularity of 3,4-methylenedioxymethamphetamine (MDMA, Ecstasy) as a drug of abuse, not much is known about the detailed mechanisms of the acute and subchronic effects of the drug. There is especially a lack of information about the distinct behavioural effects of its optical isomers (enantiomers) R- and S-MDMA compared with the racemic RS-MDMA. For this purpose, adolescent rats were repetitively treated during two treatment stages (stage 1: days 1,10; stage 2: days 15, 17, 19) with RS-MDMA (5 or 10 mg/kg) or each of the respective enantiomers (5 mg/kg). The repeated treatment started on postnatal day (PND) 32 and locomotor activity was measured on each day by means of a photobeam-equipped activity box system. RS-MDMA or S-MDMA administration led acutely to massive hyperlocomotion and subchronically, to the development of behavioural sensitization after a short habituation period. R-MDMA was free of hyperactivating effects and even decreased locomotor behaviour upon repeated treatment. Nevertheless, co-administration of R-MDMA increased the hyperactivity of S-MDMA and made the S-MDMA induced behavioural sensitization state-dependent. The animals pre-treated with R-MDMA showed a sensitized response in adulthood when tested with RS-MDMA. Our results indicated that even in the absence of substantial neurotoxicity, both MDMA enantiomers can lead to long-term changes in brain circuitry and concomitant behavioural changes when repeatedly administered in adolescence. The sensitization development was most pronounced in the animals treated with S- and RS-MDMA; the animals with R-MDMA did not develop sensitization under repeated treatment but expressed a sensitized response when challenged with RS-MDMA. [source]

Developmental profiles for multiple object tracking and spatial memory: typically developing preschoolers and people with Williams syndrome

DEVELOPMENTAL SCIENCE, Issue 3 2010
Kirsten O'Hearn
The ability to track moving objects, a crucial skill for mature performance on everyday spatial tasks, has been hypothesized to require a specialized mechanism that may be available in infancy (i.e. indexes). Consistent with the idea of specialization, our previous work showed that object tracking was more impaired than a matched spatial memory task in individuals with Williams syndrome (WS), a genetic disorder characterized by severe visuo-spatial impairment. We now ask whether this unusual pattern of performance is a reflection of general immaturity or of true abnormality, possibly reflecting the atypical brain development in WS. To examine these two possibilities, we tested typically developing 3- and 4-year-olds and people with WS on multiple object tracking (MOT) and memory for static spatial location. The maximum number of objects that could be correctly tracked or remembered (estimated from the k -statistic) showed similar developmental profiles in typically developing 3- and 4-year-old children, but the WS profile differed from either age group. People with WS could track more objects than 3-year-olds, and the same number as 4-year-olds, but they could remember the locations of more static objects than both 3- and 4-year-olds. Combining these data with those from our previous studies, we found that typically developing children show increases in the number of objects they can track or remember between the ages of 3 and 6, and these increases grow in parallel across the two tasks. In contrast, object tracking in older children and adults with WS remains at the level of 4-year-olds, whereas the ability to remember multiple locations of static objects develops further. As a whole, the evidence suggests that MOT and memory for static location develop in tandem typically, but not in WS. Atypical development of the parietal lobe in people with WS could play a causal role in the abnormal, uneven pattern of performance in WS. This interpretation is consistent with the idea that multiple object tracking engages different mechanisms from those involved in memory for static object location, and that the former can be particularly disrupted by atypical development. [source]

Visual search in typically developing toddlers and toddlers with Fragile X or Williams syndrome

DEVELOPMENTAL SCIENCE, Issue 1 2004
Gaia Scerif
Visual selective attention is the ability to attend to relevant visual information and ignore irrelevant stimuli. Little is known about its typical and atypical development in early childhood. Experiment 1 investigates typically developing toddlers' visual search for multiple targets on a touch-screen. Time to hit a target, distance between successively touched items, accuracy and error types revealed changes in 2- and 3-year-olds' vulnerability to manipulations of the search display. Experiment 2 examined search performance by toddlers with Fragile X syndrome (FXS) or Williams syndrome (WS). Both of these groups produced equivalent mean time and distance per touch as typically developing toddlers matched by chronological or mental age; but both produced a larger number of errors. Toddlers with WS confused distractors with targets more than the other groups; while toddlers with FXS perseverated on previously found targets. These findings provide information on how visual search typically develops in toddlers, and reveal distinct search deficits for atypically developing toddlers. [source]

Fear, worry, and ritualistic behaviour in childhood: developmental trends and interrelations

INFANT AND CHILD DEVELOPMENT, Issue 4 2009
Sarah V. Laing
Abstract Previous studies of childhood fear, worry, and ritualistic behaviour have been limited by restricted age ranges, narrow ranges of anxiety phenomena, non-comparable methodologies, and assessment of typical behaviour within a pathological context. Content and intensity of fear, worry, and ritualistic behaviour, and associations among these variables, were assessed through a semi-structured interview individually administered to 142 children aged 7,16 years. Common themes in the content of fear, worry, and ritualistic behaviour varied predictably with age. Intensity ratings for all three phenomena decreased with age, although this decline was only significant between 7 and 10 years. Levels were higher in girls than boys. Fear and worry were positively related, and the regular performance of rituals was related to anxiety across the age range. Worry was more strongly related than fear to engagement in ritualistic behaviour. We consider implications for the understanding of anxiety and ritualistic behaviour in typical and atypical development. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Research Review: The neurobiology and genetics of maltreatment and adversity

THE JOURNAL OF CHILD PSYCHOLOGY AND PSYCHIATRY AND ALLIED DISCIPLINES, Issue 10 2010
Eamon McCrory
The neurobiological mechanisms by which childhood maltreatment heightens vulnerability to psychopathology remain poorly understood. It is likely that a complex interaction between environmental experiences (including poor caregiving) and an individual's genetic make-up influence neurobiological development across infancy and childhood, which in turn sets the stage for a child's psychological and emotional development. This review provides a concise synopsis of those studies investigating the neurobiological and genetic factors associated with childhood maltreatment and adversity. We first provide an overview of the neuroendocrine findings, drawing from animal and human studies. These studies indicate an association between early adversity and atypical development of the hypothalamic-pituitary-adrenal (HPA) axis stress response, which can predispose to psychiatric vulnerability in adulthood. We then review the neuroimaging findings of structural and functional brain differences in children and adults who have experienced childhood maltreatment. These studies offer evidence of several structural differences associated with early stress, most notably in the corpus callosum in children and the hippocampus in adults; functional studies have reported atypical activation of several brain regions, including decreased activity of the prefrontal cortex. Next we consider studies that suggest that the effect of environmental adversity may be conditional on an individual's genotype. We also briefly consider the possible role that epigenetic mechanisms might play in mediating the impact of early adversity. Finally we consider several ways in which the neurobiological and genetic research may be relevant to clinical practice and intervention. [source]

Annotation: Deconstructing the attention deficit in fragile X syndrome: a developmental neuropsychological approach

THE JOURNAL OF CHILD PSYCHOLOGY AND PSYCHIATRY AND ALLIED DISCIPLINES, Issue 6 2004
K.M. Cornish
Background:, Fragile X syndrome is one of the world's leading hereditary causes of developmental delay in males. The past decade has witnessed an explosion of research that has begun to unravel the condition at its various levels: from the genetic and brain levels to the cognitive level, and then to the environmental and behavioural levels. Our aim in this review is to attempt to integrate some of the extensive body of knowledge to move the research a step closer to understanding how the dynamics of atypical development can influence the specific cognitive and behavioural end-states frequently observed in children and adolescents with fragile X syndrome. Methods:, We conducted a review of the current neuropsychological and neuropsychiatric approaches that have attempted to delineate the pattern of ,spared' and ,impaired' functions associated with the phenotype. Results:, The profile of findings suggests that fragile X syndrome should not be viewed merely as a catalogue of spared and impaired cognitive functions or modules. Instead, there appears to be a process of almost gradual modularisation whereby cognitive mechanisms become domain specific as a function of development itself (Karmiloff-Smith, 1992). The results of a decade of intense research point towards an early weakness in one or more components of executive control rather than single, static higher-level deficits (e.g., spatial cognition, speech processing). This weakness affects both the development of more complex functions and current performance. Conclusions:, The prevailing tendency to interpret developmental disorders in terms of fixed damage to distinct modular functions needs to be reconsidered. We offer this review as an example of an alternative approach, attempting to identify an initial deficit and its consequences for the course of development. Through better definition of the cognitive and behavioural phenotype, in combination with current progress in brain imaging techniques and molecular studies, the next decade should continue to hold exciting promise for fragile X syndrome and other neurodevelopmental disorders. [source]

Divergence of Fine and Gross Motor Skills in Prelingually Deaf Children: Implications for Cochlear Implantation,

THE LARYNGOSCOPE, Issue 8 2006
David L. Horn MD
Abstract Objective: The objective of this study was to assess relations between fine and gross motor development and spoken language processing skills in pediatric cochlear implant users. Study Design: The authors conducted a retrospective analysis of longitudinal data. Methods: Prelingually deaf children who received a cochlear implant before age 5 and had no known developmental delay or cognitive impairment were included in the study. Fine and gross motor development were assessed before implantation using the Vineland Adaptive Behavioral Scales, a standardized parental report of adaptive behavior. Fine and gross motor scores reflected a given child's motor functioning with respect to a normative sample of typically developing, normal-hearing children. Relations between these preimplant scores and postimplant spoken language outcomes were assessed. Results: In general, gross motor scores were found to be positively related to chronologic age, whereas the opposite trend was observed for fine motor scores. Fine motor scores were more strongly correlated with postimplant expressive and receptive language scores than gross motor scores. Conclusions: Our findings suggest a disassociation between fine and gross motor development in prelingually deaf children: fine motor skills, in contrast to gross motor skills, tend to be delayed as the prelingually deaf children get older. These findings provide new knowledge about the links between motor and spoken language development and suggest that auditory deprivation may lead to atypical development of certain motor and language skills that share common cortical processing resources. [source]