How Neuroscience Could Help...
By Detecting Learning Disabilities Early
By Daniel T. Willingham
I have expressed doubt about the possibility that neuroscientific findings will prove useful in designing classroom instruction in the near future. I am quite optimistic, however, that neuroscience will be successfully applied to another important educational problem—the identification of children with learning disabilities.
Here's why I believe we are on the verge of a breakthrough in this area, particularly in the identification of dyslexic children. Consider first what we already know about dyslexia. We know that children who are slow in learning language (speaking and listening) are more likely to have trouble learning to read, independent of their level of intelligence (e.g., Catts, Fey, Tomblin and Zhang, 2002). Many researchers (e.g., Tallal and Gaab, 2006) believe that this association is observed because both are caused by difficulty in phonological processing—that is, a problem in understanding subtle differences in speech sounds. There is evidence that problems in phonological processing underlie language learning impairment (e.g., Tallal and Piercy, 1973) and underlie difficulties in learning to read (e.g., Shaywitz, 1998).
It has also been shown that you can see brain differences in children with auditory processing difficulties when they are six months old, or possibly even younger. The technology works this way: While wearing a stretchy, comfortable cap that records the brain's electrical activity (which is a byproduct of neural function), an infant listens to speech sounds or to simpler auditory stimuli such as tones. Researchers have discovered significant differences in the brain responses between infants who later show a language learning impairment and those who do not. For example, in one study, 6-month-old infants listened to a rapid series of identical tones with one "oddball" tone of different pitch. The researchers found that some children showed a smaller neural response to the oddball—and that the size of this response was associated with their speaking skill at age 2 (Benasich, Choudhury, Friedman, Realpe-Bonilla, Chojnowska, and Gou, 2006).
If we can observe brain differences that are associated with language learning impairment, and if language learning impairment is associated with dyslexia, couldn't we use those same brain markers to predict who will develop dyslexia? We already know that dyslexic school-age children show these sorts of brain differences (see Temple, 2002 for a review). Several researchers are currently pursuing this line of thinking and are having some success (e.g., Espy, Molfese, Molfese and Modglin, 2004; Lyytinen, Guttorm, Huttunen, Hämäläinen, Leppänen, and Vesterinen, 2005). We don't yet have a test that can definitively say whether or not an infant will have problems with reading. But the effort has only begun, and there is every reason to be optimistic that the science will develop to that point.
Such a test would be a remarkable advance. Early intervention is critical for dyslexia. Identification of a child who is at risk for reading difficulties before reading instruction begins could be of tremendous use to educators and, of course, to students and their parents.
Daniel T. Willingham is professor of cognitive psychology at the University of Virginia and author of Cognition: The Thinking Animal. His research focuses on the role of consciousness in learning. Readers can pose specific questions to "Ask the Cognitive Scientist," American Educator, 555 New Jersey Ave. N.W., Washington, DC 20001, or to firstname.lastname@example.org. Future columns will try to address readers' questions.
Benasich, A. A., Choudhury, N., Friedman, J. T., Realpe-Bonilla, T., Chojnowska, C., and Gou, Z. (2006). The infant as a prelinguistic model for language learning impairments: Predicting from event-related potentials to behavior. Neuropsychologia, 44, 396–411.
Catts, H. W., Fey, M. E. Tomblin, J. B., and Zhang, X. (2002). A longitudinal investigation of reading outcomes in children with language impairments. Journal of Speech Language & Hearing Research, 45, 1142–1157.
Epsy, K.A., Molfese, D.L., Molfese, V.J., and Modglin, A. (2004). "Development of auditory event-related potentials in young children and relations to word-level reading abilities at age 8 years." Annals of Dyslexia, 54(1), 9-38.
Lyytinen, H., Guttorm, T. K., Huttunen, T., Hämäläinen, J. Leppänen, P. H. T., and Vesterinen, M. (2005). Psychophysiology of developmental dyslexia: A review of findings including studies of children at risk for dyslexia. Journal of Neurolinguistics, 18, 167–195.
Shaywitz, S. E. (1998). Dyslexia. New England Journal of Medicine, 338, 307–312.
Tallal, P. and Piercy, M. (1973). Developmental aphasia: Impaired rate of non-verbal processing as a function of sensory modality. Neuropsychologia, 11, 389–398.
Tallal, P. & Gaab, N. (2006). Dynamic auditory processing, musical experience and language development. Trends in Neurosciences, 29, 382–390.
Temple, E. (2002). Brain mechanisms in normal and dyslexic readers. Current Opinion in Neurobiology, 12, 178–183.