Cognitive, language and social-cognitive skills of individuals with fragile X syndrome with and without autism.
Among teens with fragile X, those who also have autism show weaker receptive language and theory of mind even when non-verbal IQ is the same.
01Research in Context
What this study did
The team compared teens and young adults who have fragile X syndrome (FXS) with and without autism.
They matched the two groups on non-verbal IQ, then gave tests for receptive language, expressive language, and theory of mind.
This design let them see if autism adds extra language or social-cognitive problems beyond FXS alone.
What they found
The FXS-plus-autism group scored much lower on receptive language and theory-of-mind tasks.
Surprisingly, their expressive language scores were no different from the FXS-only peers.
In short, understanding words and reading minds took the hit, not speaking words.
How this fits with other research
Yuhas et al. (2011) also saw that FXS-plus-autism looks different, but they measured sensorimotor gating instead of language.
The two studies seem to clash—one says the groups differ in the brain, the other in language—yet both can be true because they tested separate skills.
Busch et al. (2010) extends the idea downward to younger boys, showing that repetitive behaviors best flag autism in FXS, while our paper shows the cost in receptive language once those boys grow up.
Paul et al. (1987) found no language gap in adults, but they did not match IQ; our tighter matching may explain why we now see a clear difference.
Why it matters
When you assess an adolescent with FXS, do not assume poor talking equals poor understanding.
Check receptive language and theory of mind separately; these areas drive real-world social learning and independence.
If scores are low, add autism-specific supports like visual comprehension aids and explicit perspective-taking lessons rather than only speech drills.
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02At a glance
03Original abstract
BACKGROUND: It is not known whether those with co-morbid fragile X syndrome (FXS) and autism represent a distinct subtype of FXS; whether the especially severe cognitive delays seen in studies of young children with co-morbid FXS and autism compared with those with only FXS continue into adolescence and young adulthood; and whether autism in those with FXS is 'true autism', i.e. reflects the same underlying problems as idiopathic autism. METHOD: We compared the non-verbal IQ of adolescents and young adults with co-morbid FXS and autism (n = 10) with those with only FXS (n = 44). We then created a subsample of those with FXS only, matched on non-verbal IQ, mental age and gender (n = 21) to the subsample of those with co-morbid FXS and autism. We compared the two groups on measures of expressive language, receptive language (lexical, grammatical morphology and syntactic patterns), and a theory of mind task. RESULTS: Those with co-morbid FXS and autism had lower non-verbal IQs than those with only FXS. The participants with co-morbid FXS and autism did not perform as well as the cognitive ability- and gender-matched participants with only FXS on the three measures of receptive language or the theory of mind task; there were no differences on the expressive language measure. CONCLUSIONS: Our findings support the notion that those with co-morbid FXS and autism represent a distinct subtype of FXS, with more impairment in receptive language and theory of mind even when controlling for their lower non-verbal IQ relative to those with only FXS. The greater cognitive impairments observed in those with co-morbid FXS and autism continues into adolescence and young adulthood; and the autism seen in those with FXS appears to be the same as idiopathic autism.
Journal of intellectual disability research : JIDR, 2006 · doi:10.1111/j.1365-2788.2006.00803.x