This proposal describes a research program designed to determine the factors that contribute to the familial aggregation of specific language impairment (SLI). The first study proposed involves the collection of 40 extended family pedigrees for SLI to complement those gathered during the past project. Using these pedigrees, complex segregation analysis will be performed to determine whether there is a major genetic locus, as well as the extent to which genetic heterogeneity is present in these families. Also proposed is a twin study of SLI in which 50 pairs each of MZ and DZ twins will be studied. These data will be used to estimate the degree of genetic and environmental contributions to SLI as well as the penetrance of the genetic contribution to SLI. Within the twin study, will also be an investigation of the extent to which English morphological rule acquisition is strongly associated with genetic determinants. A third study is proposed that makes use of recent advances in genome mapping and linkage analysis. This study will look for genetic loci that are linked to the SLI phenotype in 125 affected sib-pairs. Finally we will study the reliability and diagnostic accuracy of a potential physiological phenotypic marker for SLI. Recently, averaged auditory evoked brain potentials to frequency modulated tones have been reported to be abnormal in SLI individuals with receptive language impairment. If this measure is found to be reliable and uniquely associated with SLI, it will provide a valuable physiological phenotypic marker for genetic studies of SLI. All of the research proposed is concerned with improving our understanding of the causes of a form of developmental language disorder in which the primary manifestation is one of the deficits in language development despite apparently normal auditory sensitivity and nonverbal intelligence. By determining the basis of this familial aggregation, improved early identification, and prevention may be possible.

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
Research Project (R01)
Project #
2R01DC000612-04
Application #
3217215
Study Section
Sensory Disorders and Language Study Section (CMS)
Project Start
1989-05-01
Project End
1995-06-30
Budget Start
1992-07-01
Budget End
1993-06-30
Support Year
4
Fiscal Year
1992
Total Cost
Indirect Cost
Name
University of Iowa
Department
Type
Schools of Arts and Sciences
DUNS #
041294109
City
Iowa City
State
IA
Country
United States
Zip Code
52242
Tomblin, J B; Abbas, P J; Records, N L et al. (1995) Auditory evoked responses to frequency-modulated tones in children with specific language impairment. J Speech Hear Res 38:387-92
Records, N L; Tomblin, J B (1994) Clinical decision making: describing the decision rules of practicing speech-language pathologists. J Speech Hear Res 37:144-56
Tomblin, J B; Freese, P R; Records, N L (1992) Diagnosing specific language impairment in adults for the purpose of pedigree analysis. J Speech Hear Res 35:832-43
Tomblin, J B; Hardy, J C; Hein, H A (1991) Predicting poor-communication status in preschool children using risk factors present at birth. J Speech Hear Res 34:1096-105