Receptive Vocabulary Knowledge in Low-Functioning Autism as Assessed by Eye Movements, Pupillary Dilation, and Event-Related Potentials
Annual rept. 1 Jun 2010-31 May 2011
JOHNS HOPKINS UNIV BALTIMORE MD
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Approximately 50 of individuals affected by autism fail to develop useful speech, and many of these individuals never learn to communicate in any functional way. An important scientific as well as practical question about such individuals, as well as in those with other diagnoses and a similar inability to express themselves, is whether this lack of expressive ability is necessarily accompanied by an equally severe deficit in knowledge of receptive language. Little rigorous research has been directed at this possibility, both because of the difficulty of working with such low-functioning subjects, and because of the lack of sensitivity of most traditional behavioral methodologies. Recently, however, several experimental methodologies have been developed and refined to the point where they may prove sensitive enough to provide reliable evidence of comprehension, even in the absence of more traditional behavioral responses such as speech and gesturing, and even at the individual subject level. We have been developing the use of three such research methods to attempt to detect receptive vocabulary knowledge eye movement recording, pupillary dilation monitoring, and event-related brain potentials. We have been testing whether these relatively implicit measures of comprehension actually do reflect single-word comprehension in participants in whom we expect reliable behavioral responses to serve as comparison measures normal adults, normally developing children, and high-functioning individuals with autism, as well as in low-functioning, nonverbal individuals with autism, for whom overt behavioral responses might be unreliable or even impossible. To date, we have sought to first demonstrate the use of these measures in two populations normal adults and normally developing children. Our initial results suggest that these measures similarly differentiate known from unknown words in individuals with autism, even in the absence of a behavioral response.
- Anatomy and Physiology