1. Mental Retardation & Language
Aylin Küntay
Language and Communicative Disorders
Meeting 13

2. Kanaya & Ceci (Child Development Perspective, Vol. 1, 2007)
The IQ cutoff score of 70 is used for the diagnosis of MR in the US
Give educational help to those below
2 standard deviations below the mean of 100
Represents the bottom 2.27% of the population
Problems associated with this cutoff

3. Problems
The Flynn effect: as IQ test norms get older, people perform better on them, raising the mean IQ by several points within a matter of years
Because of environmental changes such as advancements in technology, schooling, and nutrition
The MR cutoff score of 70 captures a smaller percentage of the population with every passing year
IQ tests need to be renormed every 10 or 20 years

4. Chapman: Lang Dev in DS, Pragmatics
Less initiation of communication
But mothers respond more
Lack of intelligibilty does not limit communicative attempts
Rates of linguistic imitation lower than MA controls
Imitated utterances less complex than spontaneous utterances
Limitions of auditory STM

5. Phonological development
Delayed onset of canonical babbling
Show examples from typical
But still show babbling; relatively independent of MA
More phonological errors at school-age than TD
Final consonant deletion, cluster reduction, fronting persist in adolescence
Reduced intelligibility

6. Lexical dev
Spoken vocabulary emerges at roughly the same mental ages in children with DS as in TD children
Early vocabularies accumulate slowlier in DS compared to mental age controls
Rate, but not onset, of vocabulary acquisition is slower
Current education practice emphasizes signing
The spoken vocabulary gap decreases
Might be due to phonological issues

7. Hearing
Children with DS have a high prevalence of mild to moderate hearing loss associated with otitis media (middle ear infection)
Thus some delays could be due to hearing loss

8. Syntax dev Problems in expressive syntax in free speech samples
Onset of multiword combinations occur at similar mental ages to TD
But DS shows increasing divergence of MLU from the mental-age matched controls
By age 21 months, the two groups differ significantly
Aspects of expressive lang dev stop or plateau in children with DS
Delayed language without deviance
Chapman found counterevidence to plateau
Narratives of adolescents with DS aged years show more syntactic complexity than narratives of 5-16 years

9. Language comprehension
Problems in speech perception
Problems in forming complex auditory representations
Comprehension vocabulary is an area of potential strength
No deficit in onset or acquisition of comprehension vocabulary
Fast mapping paradigm
Remembers the nonsense object given a simple novel label in a game
As good as nonverbal MA controls

10. Syntax comprehension
Syntax comprehension similar to MA-controls in childhood; lags behind in adolescence
Word order comprehension: relies on semantic plausibility, not syntactic cues
School aged children with DS show less verb-based interpretations in interpreting Noah’s Ark “act-out” sentences
The zebra goes the lion
Also needed to repeat the sentences more
DS often forgot the test sentence by the time they search for the objects

11. Reading Develop reading skills when given the educational opportunity
Wide variation

12. Summary
Normal development of comprehension relative to MA in the first 5 years of life
Emergence of a production deficit increasing in probability with mental age
Chronological age and levels of nonverbal cognitive dev are predictors of levels of language dev
To a lesser extent, hearing status affects intelligibilty of speech

13. Kids With Down Syndrome Learn Language Beyond Adolescence http://www
Chapman and her colleagues have charted the trajectory of learning skills and memory abilities in 31 individuals with Down syndrome who were ages 5-20 at the study's start. Through comprehension tests and storytelling tasks, they measured each person's ability to understand complex grammar (language comprehension) and his or her ability to speak it (language expression).
While Chapman found that some language skills may stop developing as these children reach late adolescence, she also found that language expression skills continue to improve well into young adulthood - and that their development depends on the development of language comprehension skills, which do tend to plateau.

14. Kids With Down Syndrome Learn Language Beyond Adolescence http://www
Chapman found, however, that the continued development of language expression depends on at least maintaining comprehension skills.
"The rate of change in expressive learning skills," she says, "is predicted by the rate of change in language comprehension skills." For example, if an adolescent acquires the ability to understand complex grammar more slowly, he will also acquire the ability to speak that grammar more slowly.
These findings, says Chapman, point to the importance of continuing language intervention during the teen-age years: "The study's findings suggest that there should continue to be language work in both comprehension and expression throughout teen-age and young adult years."

15. Auditory short memory as a source of individual variation
Sequential processing deficit?
Global order errors? Not really
Auditory processing deficit?
Better performance in visual short-term memory tasks than auditory tasks
Visual vs. auditory sequencing
Remembering and repeating digits; familiar word string; letter names; sentences
Correlation btw auditory STM and sentence imitation
Slower identification of incoming items
Interventions focus on visual representations
Signing, reading, writing