Lawrence D. Shriberg Ph.D., University of Kansas Medical Center Professor Emeritus, Communicative Disorders Contact Information Waisman Center UW-Madison 1500 Highland Avenue Madison, WI 53705 608-263-5982 608-263-7710 (fax) E-mail: shriberg@waisman.wisc.edu Web: http://www.waisman.wisc.edu/phonology/

Approximately 15% of 3-year-old children have speech intelligibility challenges that are not associated with known etiologies. By first grade, approximately 25% of these children (about 3.5% of all children) retain a significant speech disorder of currently unknown origin. The goals of our research are to understand the etiological origins of such disorders and to develop assessment and treatment methods that help parents and professionals make the best clinical decisions for their children. In collaboration with colleagues at several research centers we are collecting epidemiologic, molecular genetic, and speech-language data on each of three putative etiological subtypes. We suspect that the most prevalent cause of speech delay of currently unknown origin (accounting for perhaps 60% of clinical referrals) is genetic transmission of a linguistic processing deficit expressed as a problem in speech-sound production. Findings from several large family studies to date support this hypothesis. The goal in these ongoing molecular genetic projects is to identify the genotype associated with the genetically transmitted deficit and to understand its mode of transmission within families. We believe that the second most prevalent cause of speech delay of unknown origin (accounting for perhaps 30% of clinical referrals) is fluctuant hearing loss, which may occur during episodes of middle ear disease (otitis media with effusion). Our recent work using structural equation modeling techniques suggests that speech effects are most closely tied to hearing loss associated with frequent middle ear disease occurring during the 12-18 month period of linguistic development. Our findings indicate that among other possible subtypes of child speech disorder of currently unknown origin (accounting for the remaining approximate 10% of clinical referrals), the most prevalent subtype involves a genetically transmitted deficit in speech-motor control. Several ongoing collaborative genetic projects in apraxia of speech are developing the phenotype for this disorder, using perceptual and acoustic techniques to quantify affected children's and family members' speech and prosody. Shriberg LD, Ballard KJ, Tomblin JB, Duffy JR, Odell KH, Williams CA. Speech, prosody, and voice characteristics of a mother and daughter with a 7;13 translocation affecting FOXP2. J Speech Lang Hear Res. 2006 Jun;49(3):500-25.   Stein CM, Millard C, Kluge A, Miscimarra LE, Cartier KC, Freebairn LA, Hansen AJ, Shriberg LD, Taylor HG, Lewis BA, Iyengar SK. Speech Sound Disorder Influenced by a Locus in 15q14 Region. Behav Genet. 2006 Jun 20; [Epub ahead of print] Lewis BA, Freebairn LA, Hansen AJ, Stein CM, Shriberg LD, Iyengar SK, Gerry Taylor H. Dimensions of early speech sound disorders: A factor analytic study. J Commun Disord. 2006 Mar-Apr;39(2):139-57. Shriberg LD, Lewis BA, Tomblin JB, McSweeny JL, Karlsson HB, Scheer AR. Toward diagnostic and phenotype markers for genetically transmitted speech delay. J Speech Lang Hear Res. 2005 Aug;48(4):834-52. Smith, S. D., Pennington, B. F., Boada, R., & Shriberg, L. D. (2005). Linkage of speech sound disorder to reading disability loci. Journal of Child Psychology & Psychiatry, 46, 1057-1066.   Click to search National Library of Medicine and PubMed for other publications by Dr. Shriberg

Last updated 8/28/2006 by rowley@waisman.wisc.edu