The purpose of this project, Origins of Communication Disorders in Infants of Substance Abusing Mothers (ISAMS), is to understand the nature and etiology of early delays in language and associated domains in infants with prenatal exposure to cocaine and/or methamphetamine. Previous research in our laboratories suggests that ISAMS constitute a new risk group for early language impairment, one that is growing at an alarming rate. Illicit use of these stimulants is widespread in spite of many morbidities associated with their use; among pregnant women, it is estimated at 11% nationwide. Pregnancy complications, poor neonatal outcome and profound changes in neurophysiologic and behavioral profiles of affected infants are known. We reported a significantly high incidence (35%) of echoencephalographic abnormalities in term, stimulant-exposed but otherwise well infants, suggestive of antenatal structural CNS injury. These structural changes are concentrated in the basal ganglia and the frontal lobes. Followup data from our laboratory and others show substantial developmental deficits in this group, particularly in the domains of language and social functioning; furthermore, the linguistic and social deficits appear to widen across the second year of life, in both longitudinal and cross-sectional samples. In this project, 40 children exposed prenatally to cocaine and/or methamphetamine (ISAMS) will be identified in infancy and toddlerhood and followed longitudinally. Parental academic, mental and physical health histories will be collected to further define the genetic and intrauterine background of participating children. We propose to evaluate two overlapping longitudinal cohorts of ISAMS, together with appropriate control children, focussing on the emergence of language and its cognitive and social correlates across this critical age range. A particular emphasis is placed on the possible role of frontal lobe functions in early language and communicative development. At project completion, we will have a detailed developmental profile of this population, for comparison with other forms of language and cognitive impairment under study across the Program Project as a whole. These comparative analyses will help us to determine whether and to what extent ISAMS constitutes a new form of specific language impairment, a form similar to the deficits studies in Project 1, or a language delay in the context of more general retardation in cognitive function (similar in shape but not severity to Down Syndrome children in Project 3). We can also determine whether ISAMS with documented frontal lobe injury display a profile of language impairment that is similar in onset and subsequent resolution to the profiles observed in other forms of focal brain damage (Project 2), and/or a unique language/cognition profile that may be systematically related to bilateral deficits in frontal cortex. Results of this study will be of enormous practical value to school systems and other institutions preparing to cope with the results of a national epidemic in substance abuse, and they will contribute to our understanding of neurochemical and neuroanatomical factors in language development and language disorders.
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