Speech and Language Skills of Individuals With Prader-Willi Syndrome:
By: Barbara A. Lewis, Lisa Freebaim, Shauna Heeger, and Suzanne B Cassidy
Prader-Willi Syndrome is a genetic syndrome affecting 1 in 10,000-25,000 individuals. Considering how rare it is, I find it amazing that I now have two kiddos with this syndrome on my caseload. So this month for Research Tuesday, I read an article that investigated the speech and language skills of individuals with Prader-Willi. It was interesting and relevant to me because of the two little girls I treat, and I hope it will be to you as well.
The first thing that struck me when researching this syndrome is the lack of information provided by mainstream websites on the subject. It's a good wake up call to any therapist who thinks they can just briefly look up a syndrome online to get information. I found the information provided on mainstream websites downplayed the speech/language and cognitive impairments that can be found in these individuals. For example:
The Mayo-Clinic states that individuals with PWS may have "a poor sucking reflex due to low muscle tone," which initially leads to poor weight gain. In regards to speech and language deficits the Mayo-Clinic says this: "Speech is often delayed. Poor articulation of words may be an ongoing problem into adulthood." In regards to intellectual abilities of individuals with PWS the Mayo-Clinic states that individuals may have "mild to moderate impairment in intellectual functioning, such as thinking, reasoning and problem-solving (intellectual disability)...even those without significant intellectual disability have some learning disabilities."
The Prader-Willi Association sights the following characteristics of children with this syndrome:
-Feeding problems and poor weight gain in infancy
-Global developmental delay before age 6; mild to moderate mental retardation or learning problems in older children
One of the purposes of the article I read was to "examine the existing literature on the speech and language skills of individuals with PWS, and to report on the speech and language findings of a relatively large cohort of individuals with PWS."
Method:
The researchers examined the speech and language skills of 55 individuals with PWS. Ages ranged from 6 months to 42 years. Diagnosis of Prader-Willi was confirmed by a medical geneticist for each participant. Categories examined included: intelligence, articulation and phonology, oral motor skills, expressive grammar, prosody and voice characteristics, lexical comprehension and expression, and narrative abilities. Individuals were divided into age groups and tested using commonly used standardized tests such as the Goldman Fristoe Test of Articulation, the Khan-Lewis Phonological Process Analysis, the Peabody Picture Vocabulary Test, the Expressive One-Word Picture Vocabulary Test, and the Standford Binet Intelligence Scale.
Results:
Oral Motor Skills and Articulation:
-91% demonstrated some degree of oral motor deficits characterized by poor tongue mobility, shortness of the palate, and incoordination of the articulators.
-85% demonstrated mild to severe articulation impairment
-Articulation deficits remained present through adolescence
Voice:
-20% presented with higher than normal pitch
-24% presented with lower than normal pitch
-62% presented with hypernasality
-14% presented with hyponasality
-Harsh vocal quality was noted in 26% of participants
-Hoarse vocal quality was noted in 13% of participants
Language Skills:
-participants presented with impaired vocabulary, difficulty including story grammar components, and difficulty with reading comprehension
-deficits in reading comprehension persisted until adulthood
-participants also demonstrated decreased narrative abilities
In Summary:
The researchers outlined a general course of development for individuals with Prader-Willi Syndrome. That course of development was described as follows:
-6 mos-2 years: infants present with weak cry, feeding difficulties, hypotonia, and speech/language delay.
-2-5 years: first words begin to emerge, oral motor skills remain poor and intelligibility is poor
-5-12 years: residual articulation deficits, decreased receptive/expressive language abilities (including poor narrative and story telling abilities), hypernasality or hyponasality may be present along with abnormal vocal pitch
-12 years through adulthood: some articulation errors, some receptive/expressive language deficits, poor narrative abilities, and poor conversational skills, abnormal pitch and resonance characteristics
As you can see, the speech and language deficits of individuals with Prader-Willi Syndrome are far more complex than indicated by a number of mainstream websites providing information about the disorder. Many families rely on the internet to gather information about what to expect as their child grows and develops. As speech-language pathologists it is important that we complete studies like this one in relation to all of the syndromes we treat. In addition, it is important that we provide this information to our families and recommend intervention as early as possible. Clinical judgment and thorough testing and observation should be completed to provide the best services possible. Furthermore, SLP's should be actively educating the public about how syndromes such as Prader-Willi can impact an individual's ability to communicate functionally in their environment. Otherwise, the affects of these syndromes will continue to be downplayed by doctors and insurance companies.
