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The speech and language of 55 individuals (27 males and 28 females) with Prader-Willi syndrome (PWS), aged from 6 months to 42 years, were examined through standardized testing and spontaneous speech sample analysis. While great variability was noted in speech and language abilities, most subjects presented with speech sound errors characterized by imprecise articulation (85%), and oral motor difficulties (91%). Hypernasality was noted in 62% and hyponasality in 14%. Other speech characteristics included a slow speaking
rate, flat intonation patterns, abnormal pitch of the voice, and harsh/hoarse voice quality. Narrative retelling abilities were poor, with specific deficits in sequencing of story events. Individuals with PWS as a result of deletions of chromosome 15 did not differ significantly in speech and language from individuals with PWS as a result of uniparental disomy.
Key Words: syndrome, genetic, speech, language, chromosome
Prader-Willi syndrome (PWS) is a complex multisystem genetic disorder that results in infantile hypotonia, developmental delays and mental retardation, behavioral disorders, characteristic facial appearance, obesity, hypogonadism, and short stature (Cassidy, 1997). Most individuals with PWS present with some type of speech and language deficit, although there is great variability in the type and severity of the disorder, ranging from individuals who are nonverbal to those who develop normal speech and language skills by adulthood. The speech-language pathologist (SLP) may become involved as early as birth to treat feeding difficulties and may continue to serve individuals with PWS for communication disorders throughout their lifespan.
The goals of the present article are to summarize the genetic and phenotypic characteristics of PWS, to examine the existing literature on the speech and language skills of PWS, and to report on the speech and language findings of a relatively large cohort of individuals with PWS. Previous descriptions of speech and language skills have been based on a small number of individuals and have not examined the developmental course of the speech and language disorder. Many studies have not distinguished between speech sound errors due to poor oral motor skills and structural deviations and errors due to phonological deficits. Further, studies have not attempted to associate speech and language characteristics to a particular causative genetic abnormality.
Genetic Basis of PWS
PWS results from the loss of function of genes that...