1. Is There a Preference for Low-Level Linguistic Processing in Autism?
Brian D. Roper Ph.D., M.S. CCC-SLP & Jose A. Ortiz M.A. CCC-SLP
BACKGROUND
Language Processing in Low-Functioning Autism
Word Monitoring Task
Language processing deficits are a core feature of the linguistic phenotype of low-functioning autism (LFA).
Comprehension is very often more impaired than expression (Boucher, 2003).
Masked by use of formulaic speech.
Rapin and Dunn (2003) - none of the 229 ASD children sampled were tested as having normal comprehension.
If language comprehension deficits are universal (Boucher et al., 2007), what is the nature of the of the abnormality?
Clues to how LFA process language can be derived from the quality of their expressive output.
The LFA individual’s memorized utterances “denote but fail to connote” (Fay and Schuler 1980).
Reliance on grammatically correct scripts used as wholes (Boucher 2003).
Spontaneous language tends to be laborious and inefficient.
LFA may make use of low-level phonological information but fail to connect such information with underlying meaning (Minshew and Williams, 2007).
Are LFA individuals making use of syntactical and semantic information when processing language?
If not, is there a reliance on processing acoustical properties of the speech signal?
Methods
Training Phase
Subjects read 54 words presented on a computer screen individually.
27 are targets in the test phase, 27 are distractors
Test Phase
Subjects see a target word on a screen and read it aloud.
Then hear a sentence containing the target word.
Three types of sentences.
Normal Prose – “The table was set for dinner. We put a spoon next to all the soup bowls.”
Semantically anomalous sentences – “The stool was flown by bedtime. Nobody swam the spoon next to the fence.”
Syntactically and semantically anomalous sentences – “Flown by stool bedtime the was. Fence the swam spoon next nobody the to.”
Dependent Variable = reaction time (RT) to press space bar when subject hears target word.
Hypothesis
If LFA exhibit preferential processing of low-level processing, less variation in RT between sentence types when compared to other subject groups.
Could be processing low-level physical properties in relative isolation to stored representations.
Indicative of an underconnected cortical system?
What is Language Processing?
Language processing is the of “mapping meaning onto sound (Marslen-Wilson and Tyler, 1987).
“Tripartite” model of language processing (Hagoort, 2005):
Sound – Heschl’s gyrus with the superior temporal sulcus (Peele et al, 2010; Uppenkamp et al, 2006).
Form (syntax) – Left inferior frontal gyrus, bilateral anterior STG and left posterior temporal-parietal regions (Tyler and Marlsen-Wilson, 2008).
Meaning (semantics) – Left inferior frontal cortex, left medial temporal gyrus, superior temporal gyrus (Tyler and Marlsen-Wilson, 2008).
To a degree, language is processed in a hierarchical fashion.
“Bottom-up processing”
Evidence that higher linguistic processes interact and inform low-level processes.
Phonemic restoration - context alters what people hear.
In online language comprehension, syntactical and semantic processing interact with phonological processing (Marslen-Wilson and Tyler, 1980; Hagoort, 2005).
ðəfɑrmərtʃeɪsɪzðədəklɪŋzɔnðəreɪniːdeɪz
“the farmer chases the ducklings on the rainy days”
References
Boucher, Jill (2003). Language Development in Autism. International Congress Series, 1254,
Boucher, J., Mayes, A., Bigham, S. Memory, Language and Intellectual Ability in Low-Functioning Autism. In Boucher, J. and Bowler, D. (Eds) Memory in Autism: Theory and Evidence. Cambridge University Press, 2007.
Fay, W. and Schuler, A.L. (1980). Emerging Language in Autistic Children. London: Edward Arnold
Hagoort, Peter (2005). On Broca, Brain and Binding: A New Framework. Trends in Cognitive Sciences, 9(9),
Marslen-Wilson, W., and Tyler, L. (1980). The temporal structure of spoken language understanding. Cognition, 8, 1-71.
Minshew, N.J. and Williams, D.L. (2007). The New Neurobiology of Autism: Cortex, Connectivity and Neuronal Organization. Archives of Neurology, 64(7),
Peelle, J., Johnstrude, I. S., & Davis, M. H. (2010). Hierarchical Processing for Speech in Human Auditory Cortex and Beyond. Frontiers in Human Neuroscience , 4 (51), 1-3.
Rapin, I., & Dunn, M. (2003). Update on the Language Disorders of Individuals on the Autistic Spectrum. Brain & Development , 25,
Tyler, L., & Marslen-Wilson, W. (2008). Fronto-Temporal Systems Supporting Spoken Language Comprehension. Philosophical Transactions of the Royal Society , 363,
Uppenkamp, S., Johnstrude, ,. I., Norris, ,. D., Marslen-Wilson, M., & Patterson, R. D. (2006). Locating the Initial Stages of Speech-sound Processing in Human Temporal Cortex. NeuroImage , 31,
Analyzing Language Processing in Low-Functioning Autism
Roper and Ortiz are designing and piloting a computerized word monitoring task to assess the influence syntactical and semantic information has on sentence comprehension in low-functioning ASD.
Subjects
High-functioning ASD (HFA), LFA, Down’s Syndrome, typically developing.
Ages with basic reading skills.