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Biomedical subjects

Geraldine Dawson

Publications and source records attributed to Geraldine Dawson.

44 records · Page 3Linked to original sources
PubMed2002

Stress hormone levels of children of depressed mothers.

Research suggests that disruptions in early caretaking can have long-term effects on the hypothalamic-pituitary-adrenal (HPA) axis, which mediates the stress response. Children of depressed mothers are at increased risk for developing internalizing problems in part because of disruptions in their caretaking environment. The present study investigated whether children of depressed mothers exhibit elevated salivary cortisol levels. Salivary cortisol samples were collected from 45 7- to 8-year-old children of mothers with a history of depression and 29 children of nondepressed mothers. Samples were collected soon after arrival to the laboratory and after a mild laboratory stressor and at home after wakeup and before bedtime. Children who had elevated levels of intemalizing symptoms and whose mothers had a history of depression showed elevated laboratory baseline cortisol levels. Children who were reported to have clinically significant internalizing symptoms were also more likely to show an elevated stress response to a mild laboratory stressor. When the longitudinal history of maternal depression was examined, matemal depression during the child's first 2 years of life was the best predictor of elevations in baseline cortisol at age 7 years. This study provides evidence that internalizing symptoms exist in conjunction with a more reactive hormonal stress system in children of depressed mothers. The results also provide preliminary evidence that exposure to maternal depression in the first 2 years of life may be related to children's cortisol levels later in life.

Arousal↗
PubMed2002

Defining the broader phenotype of autism: genetic, brain, and behavioral perspectives.

Achieving progress in understanding the cause, nature, and treatment of autism requires an integration of concepts, approaches, and empirical findings from genetic, cognitive neuroscience, animal, and clinical studies. The need for such integration has been a fundamental tenet of the discipline of developmental psychopathology from its inception. It is likely that the discovery of autism susceptibility genes will depend on the development of dimensional measures of broader phenotype autism traits. It is argued that knowledge of the cognitive neuroscience of social and language behavior will provide a useful framework for defining such measures. In this article, the current state of knowledge of the cognitive neuroscience of social and language impairments in autism is reviewed. Following from this, six candidate broader phenotype autism traits are proposed: (a) face processing, including structural encoding of facial features and face movements, such as eye gaze; (b) social affiliation or sensitivity to social reward, pertaining to the social motivational impairments found in autism; (c) motor imitation ability, particularly imitation of body actions; (d) memory, specifically those aspects of memory mediated by the medial temporal lobe-prefrontal circuits; (e) executive function, especially planning and flexibility; and (f) Language ability, particularly those aspects of language that overlap with specific language impairment, namely, phonological processing.

Autistic Disorder↗
PubMed2002

A randomized, double-blind, placebo-controlled trial of porcine versus synthetic secretin for reducing symptoms of autism.

OBJECTIVE: To compare the effects of a single dose of biologic and synthetic porcine secretin to placebo on a variety of autism symptoms. METHOD: Eighty-five children with autism without other medical conditions and not taking other psychotropic medications participated (ages between 3 and 12 years, mean IQ = 55). Children were grouped into trios matched by age and communication level and then randomly assigned to one of three treatment groups: biologic secretin (2 CU/kg), synthetic secretin (0.4 microg/kg), and placebo. Measures collected 1 week before and 4 weeks after infusion included autism symptoms, language skills, and problem behaviors, gathered from parents, teachers, and investigators, who were all blind to treatment. Two-factor, repeated-measures analyses of variance (3 treatment levels by 2 repeated measures, pre- and postinfusion) were used to examine efficacy. RESULTS: Direct observation measures did not show change over time related to secretin. Parent reports showed an overall reduction of symptom severity for all treatment groups, including the placebo group. One teacher-report measure showed decreases in autism symptoms in the placebo and synthetic secretin groups. CONCLUSIONS: No evidence that either biologic or synthetic secretin provided amelioration of symptoms beyond placebo was observed. This held true when children with and without gastrointestinal problems were examined separately.

Autistic Disorder↗
PubMed2002

Fluorine magnetic resonance spectroscopy measurement of brain fluvoxamine and fluoxetine in pediatric patients treated for pervasive developmental disorders.

OBJECTIVE: Pediatric populations, including those with autistic disorder or other pervasive developmental disorders, increasingly are being prescribed selective serotonin reuptake inhibitors (SSRIs). Little is known about the age-related brain pharmacokinetics of SSRIs; there is a lack of data regarding optimal dosing of medications for children. The authors used fluorine magnetic resonance spectroscopy ((19)F MRS) to evaluate age effects on whole-brain concentrations of fluvoxamine and fluoxetine in children taking SSRIs. METHOD: Twenty-one pediatric subjects with diagnoses of autistic disorder or other pervasive developmental disorders, 6-15 years old and stabilized with a consistent dose of fluvoxamine or fluoxetine, were recruited for the study; 16 successfully completed the imaging protocol. Whole-brain drug levels in this group were compared to similarly acquired data from 28 adults. RESULTS: A significant relationship between dose and brain drug concentration was observed for both drugs across the age range studied. Brain fluvoxamine concentration in the children was lower, consistent with a lower dose/body mass drug prescription; when brain concentration was adjusted for dose/mass, age effects were no longer significant. Brain fluoxetine concentration was similar between age groups; no significant age effects on brain fluoxetine drug levels remained after adjustment for dose/mass. Observations of brain fluoxetine bioavailability and elimination half-life also were similar between age groups. CONCLUSIONS: These findings suggest that fluvoxamine or fluoxetine prescriptions adjusted for dose/mass are an acceptable treatment approach for medicating children with autistic disorder or other pervasive developmental disorders. It must be determined whether these findings can be generalized to other pediatric populations.

Adolescent↗
PubMedDate not supplied

Neurocognitive function and joint attention ability in young children with autism spectrum disorder versus developmental delay.

Studies have shown that young children with autism are not impaired on prefrontal tasks relative to what would be expected for their mental age, raising questions about the executive dysfunction hypothesis of autism. These studies did not include ventromedial prefrontal tasks, however. The present study examined whether young children with autism spectrum disorder (ASD) are impaired on ventromedial prefrontal tasks, and whether performance on such tasks is correlated with a core autism symptom, joint attention ability. Seventy-two 3- to 4-year-old children with ASD, 34 3- to 4-year-old developmentally delayed children, and 39 12- to 46-month-old typically developing children, matched on mental age, were administered ventromedial and dorsolateral prefrontal tasks and joint attention tasks. Children with ASD performed similarly to comparison groups on all executive function tasks, indicating that at this early age, there is no autism-specific pattern of executive dysfunction. Ventromedial, but not dorsolateral, prefrontal task performance was strongly correlated with joint attention ability, however. The ventromedial prefrontal cortex is hypothesized to play a role in the development of joint attention and possibly some aspects of the autistic syndrome.

Attention↗
PubMedDate not supplied

Neural correlates of face and object recognition in young children with autism spectrum disorder, developmental delay, and typical development.

This study utilized electroencephalographic recordings to examine whether young children with autism spectrum disorder (ASD) have impaired face recognition ability. High-density brain event-related potentials (ERPs) were recorded to photos of the child's mother's face versus an unfamiliar female face and photos of a favorite versus an unfamiliar toy from children with ASD, children with typical development, and children with developmental delay, all 3 to 4 years of age (N = 118). Typically developing children showed ERP amplitude differences in two components, P400 and Nc, to a familiar versus an unfamiliar face, and to a familiar versus an unfamiliar object. In contrast, children with ASD failed to show differences in ERPs to a familiar versus an unfamiliar face, but they did show P400 and Nc amplitude differences to a familiar versus an unfamiliar object. Developmentally delayed children showed significant ERP amplitude differences for the positive slow wave for both faces and objects. These data suggest that autism is associated with face recognition impairment that is manifest early in life.

Autistic Disorder↗
PubMedDate not supplied

Preschool outcomes of children of depressed mothers: role of maternal behavior, contextual risk, and children's brain activity.

Children of depressed mothers are at risk for behavioral and emotional problems. Infants of depressed mothers exhibit behavioral disturbances and atypical frontal brain activity. The mechanisms by which children develop such vulnerabilities are not clear. Three-year-old children of mothers with (N = 65) and without (N = 59) a history of depression were assessed in terms of behavior problems and brain electrical activity. Children of mothers with chronic depression exhibited lower frontal and parietal brain activation compared with children of mothers without depression and those whose depression remitted. Depressed mothers reported higher contextual risk (e.g., marital discord and stress) and their children had more behavior problems. Children's frontal brain activation and contextual risk level mediated the relation between maternal depression and child behavior problems.

Adult↗