Pre-Collegiate Global Health Review
A More Inclusive World: New Test to Study Language Development in Youth with Down Syndrome
Grace Murphy, Belmont High School, Belmont, Massachusetts, USA
Down syndrome is the most common chromosomal disorder. Each year, 1 out of every 700 babies are born with Down syndrome, and between 1979 and 2003, the number of babies born with Down syndrome increased by around 30% (CDC, 2021). Knowing that language skills are vital for positive interactions, treatments that aim to increase expressive language skills in individuals with Down syndrome are shown to foster widespread benefits and greatly improve the quality of life for this growing population. But how are the appropriate actions decided by care teams? Expressive language sampling (ELS) is a recently emerging tool being used to measure communication development in youths with Down syndrome.
Figure 1: Estimated number of people with Down syndrome in the US from 1950 to 2010 (Neuroscience News, 2016).
In a study performed by Thurman et al. (2021) published in Journal of Neurodevelopmental Disorders, ELS technology was evaluated to decide its effectiveness in generating spoken language outcome measures in youth with Down syndrome. Researchers were hoping to use this technology to increase information in treatment and research for the community. Four university testing sites began by recruiting and testing possible participants, who had to display an intellectual disability, indicated by an IQ below 70. Additional inclusion criteria were the willingness of both youth and caregiver to participate in the protocol, the youth using speech as their primary mode of communication, the use of English as their primary language, and not demonstrating serious hearing loss or visual impairment. The sample was made up of 107 individuals with Down syndrome (55 males and 52 females) between the ages of 6 and 23 who presented with an intellectual disability, measured by an IQ under 70. Information was gathered by observing and analyzing expressive language samples collected in two separate contexts (conversation and narration) during an initial test and a retest. The examiners who administered ELS procedures used standardized measures to elicit spontaneous speech in these two naturalistic contexts. The constructs measured in this study were the participant’s separate conversation and narration skills in relation to five primary variables computed for each language sample: talkativeness, lexical diversity (vocabulary), syntax (the arrangement of words and phrases), dysfluency (utterance planning) and unintelligibility (speech articulation) (Yehya, 2021).
The conversation construct consisted of an interview-like conversation with an examiner. The examiner used open-ended prompts and broad follow-up questions to encourage the participant to talk as much as possible over a 12 minute sample period, while limiting their own speech. The examiner referred to a scripted list of topics to discuss, starting with an individual topic of interest and then moving on to a standardized topic. The narration construct consisted of the participant receiving a wordless picture book. The examiner silently showed the youth each page to get a sense of the story, allowing about 10 seconds per page, and when this first showing was completed, the youth would then be asked to tell the story. The examiner controls the turning of the pages, and their responses and prompts are standardized (Thurman et al., 2021).
The researchers found that most of the 107 participants with Down syndrome (ages 6-23) were meaningfully engaged by the conversation and narration tasks presented, with non-compliance rates only at 6.5% for conversation and 14% for narration. Additionally, the test-retest reliability of the study was positive. Results indicated that the ELS variables (from both conversation and narration tasks) in the test and 4-week later retest visit were extremely correlated and highly reproducible (Thurman et al., 2021). It showed that the vocabulary, syntax and speech intelligibility variables particularly demonstrated strong validity as outcome measures, making these ELS procedures feasible in testing the majority of participants. Prior to this study, researchers were unable to confidently measure changes in language development for individuals with intellectual disabilities throughout their treatment process. But, ELS can now be used as a tool to measure language development, leading to effective interventions and improvements in the population’s speech and language.
These results can lead to life-changing impacts for individuals with Down syndrome, many of whom have trouble communicating and expressing themselves. Using this new information, speech-language therapists can help children with Down syndrome improve their language skills by understanding the effectiveness of alternate means of communication, such as sign language and pictures, in developing maximum speech. Language plays a critical role in social functioning, cognitive development, academic achievement, and daily living skills, and consequently these delays are some of the largest barriers to independence and community inclusion. With a way to test and help develop treatments using ELS, the world can become an increasingly welcoming place for those with Down syndrome.
Centers for Disease Control and Prevention. (2021, April 06). Facts About Down Syndrome. Retrieved July 16, 2022, from https://www.cdc.gov/ncbddd/birthdefects/downsyndrome.html
Ridings, M. (2016, September 09). Study estimates numbers of people with Down Syndrome in the US since 1950 [Digital Image]. Retrieved August 25, 2022, from https://neurosciencenews.com/down-syndrome-rate-us-5002/
Thurman, A., Edgin, J., Sherman, S., Sterling, A., McDuffie, A., Berry-Kravis, E., . . . Abbeduto, L. (2021, April 08). Spoken language outcome measures for treatment studies in down syndrome: Feasibility, practice effects, test-retest reliability, and construct validity of variables generated from expressive language sampling. Retrieved July 16, 2022, from https://jneurodevdisorders.biomedcentral.com/articles/10.1186/s11689-021-09361-6#Sec1
Yehya, N. A. (2021, April 8). New test to study language development in youth with Down syndrome. Retrieved July 16, 2022, from https://health.ucdavis.edu/health-news/newsroom/new-test-to-study-language-development-in-youth-with-down-syndrome/2021/04