The hallmark of fetal alcohol spectrum disorders (FASD) is the significant neurobehavioral impairment that occurs across the spectrum. A profile of these deficits is emerging, but the clinical utility of such a profile requires continued research to improve its accuracy and specificity. One deficit that is often noted in FASD is in the domain of attention. Based on previous studies of attention, documenting deficits in spatial orienting and sustained visual attention, we propose a broadened investigation of the mechanisms of visual attention deficits using state of the art methodology. More specifically, the proposed study will use the Attention Network Test (ANT), which was designed to assess three attention networks (orient, alert, executive control) that underlie visual attention and are dependent on the integrity of dissociable brain regions and neurotransmitter systems. Both neuropsychological and functional magnetic resonance imaging (fMRI) versions of the ANT will be used to assess differential behavioral and brain response related to the three attention networks in children with FASD and typically developing controls. Findings of differential impairments across the networks within the FASD group may help to identify areas of relative strengths and deficits in this population, contributing to the developing neurobehavioral profile of heavy prenatal alcohol exposure. In addition, analyzing blood oxygen level dependent (BOLD) response to the ANT will allow for examination of the neural underpinnings of observed attention deficits. Based on previous studies, we hypothesize a profile characterized by relatively greater deficits in the alerting and executive control networks in the FASD group. An additional goal of the current application is to examine the specificity of observed effects by including children with full scale IQ (FSIQ) scores below the average range (FSIQ<85) in our control group. This will allow us to compare the attention performance between the groups with and without controlling overall IQ. We hypothesize that the observed attention deficits will occur even in the absence of IQ differences. We plan to test 80 children (ages 8-12y) in two groups (FASD and Control) with the neuropsychological version of the ANT and 60 adolescents (ages 13-16y) on the fMRI version. For both tasks, the control group will be larger than the FASD group to allow for the additional subjects with below average IQ scores. The proposed study is consistent with the NIAAA strategic plan for 2009-2014, which cited refining the neurodevelopmental signature of FASD as a critical research need. Our focus on neuropsychological features of FASD, the inclusion of neuropsychological and fMRI procedures, and our interest in the relation between attention and lowered IQ directly addresses these recommendations.
This project is directly relevant to public health concerns surrounding the behavioral effects of heavy prenatal alcohol exposure. The resulting data will clarify the nature and neural underpinnings of attention deficits in fetal alcohol spectrum disorders, and as a result will help refine the profile of effects that are specific to this population and improve diagnosis of alcohol-affected individuals. Improved delineation and identification of these features will ultimately lead to improved treatment by indentifying aspects of attention as well as underlying brain regions and neurotransmitter systems affected by heavy prenatal alcohol exposure.
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