This research program has developed a unique classification system for Speech Sound Disorders (SSD) termed the Speech Disorders Classification System (SDCS). Research goals are to understand the causal pathways that lead to each of eight subtypes of SSD so that clinicians can select the appropriate intervention approach for each child, and researchers can conduct studies that should lead to prevention of some subtypes of SSD. The final phase of this project will complete all goals by obtaining new information in three study series. Diagnostic Accuracy Studies. Using a unique risk factor classification system for SSD, including genomic and environmental variables, we will document speech error differences associated with how children encode speech signals, how they store and access linguistic representations of speech, and how they transcode representations into the movement gestures for speech production. Prevalence Studies. Our research indicates significant differences in the prevalence of subtypes of SSD and in the rates and types of normalization outcomes. The proposed research will estimate both clinical prevalence rates and population prevalence rates for six subtypes of SSD. Speech Processing Studies. Our studies have motivated questions about speech processing differences and similarities in speakers from different causal backgrounds. In addition to studies of speakers with speech delay and motor speech disorders of unknown origin, our questions will be informed by assessment data from speakers with Down syndrome, 22q11.2 deletion (Velocardiofacial) syndrome, Galactosemia, Joubert syndrome, and Rolandic Epilepsy. A number of hypotheses about speech processing differences between and within study groups will be addressed, including a focus on support for a speech sound disorder termed Childhood Apraxia of Speech and a placeholder motor speech disorder we term Motor Speech Disorder-Not Otherwise Specified. Relevance The high prevalence of SSD at 6 years of age (3.8%: Shriberg, Tomblin, and McSweeny, 1999), persisting to 8 years of age (3.6%: Wren et al., 2009), places SSD among the most frequently occurring childhood disorders warranting public health resources for research in prevention, assessment, and treatment. SSD puts a child at risk for literacy development, reduced peer acceptance, and limitations in vocational options. Findings from this research should have substantial impact on research and clinical practice for this significant childhood communicative disorder.

Public Health Relevance

Approximately 4% of six-year-old children in the United States have speech sound disorders of unknown origin that place them at risk for reading disability, psychosocial handicap, and vocational limitations. This research seeks to identify the causes of children's speech sound disorders, with emphasis on the individual and multiple roles of heredity, middle ear disease, speech motor control, and psychosocial processes as risk factors. Our goal is to develop procedures to identify which one or more causal pathway is most likely for each child so clinicians can make accurate prognoses and provide targeted treatment, and researchers can develop ways to prevent speech sound disorders and/or reduce their negative effects on children's development.

National Institute of Health (NIH)
National Institute on Deafness and Other Communication Disorders (NIDCD)
Research Project (R01)
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Study Section
Language and Communication Study Section (LCOM)
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Shekim, Lana O
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University of Wisconsin Madison
Schools of Arts and Sciences
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Raca, Gordana; Baas, Becky S; Kirmani, Salman et al. (2013) Childhood Apraxia of Speech (CAS) in two patients with 16p11.2 microdeletion syndrome. Eur J Hum Genet 21:455-9
Shriberg, Lawrence D; Lohmeier, Heather L; Strand, Edythe A et al. (2012) Encoding, memory, and transcoding deficits in Childhood Apraxia of Speech. Clin Linguist Phon 26:445-82
Potter, Nancy L (2011) Voice disorders in children with classic galactosemia. J Inherit Metab Dis 34:377-85
Shriberg, Lawrence D; Paul, Rhea; Black, Lois M et al. (2011) The hypothesis of apraxia of speech in children with autism spectrum disorder. J Autism Dev Disord 41:405-26
Shriberg, Lawrence D; Potter, Nancy L; Strand, Edythe A (2011) Prevalence and phenotype of childhood apraxia of speech in youth with galactosemia. J Speech Lang Hear Res 54:487-519
Stein, Catherine M; Lu, Qing; Elston, Robert C et al. (2011) Heritability estimation for speech-sound traits with developmental trajectories. Behav Genet 41:184-91
Shriberg, Lawrence D; Fourakis, Marios; Hall, Sheryl D et al. (2010) Extensions to the Speech Disorders Classification System (SDCS). Clin Linguist Phon 24:795-824
Shriberg, Lawrence D; Fourakis, Marios; Hall, Sheryl D et al. (2010) Perceptual and acoustic reliability estimates for the Speech Disorders Classification System (SDCS). Clin Linguist Phon 24:825-46
Shriberg, Lawrence D; Lohmeier, Heather L; Campbell, Thomas F et al. (2009) A nonword repetition task for speakers with misarticulations: the Syllable Repetition Task (SRT). J Speech Lang Hear Res 52:1189-212
Potter, N L; Lazarus, J-A C; Johnson, J M et al. (2008) Correlates of language impairment in children with galactosaemia. J Inherit Metab Dis 31:524-32

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