Why non-speaking autism probably has nothing to do with motor control problems or speech apraxia
FC proponents typically justify FC in part by claiming that autism entails major problems with motor control—that is, problems precisely executing body movements. Traditional FC proponents use this claim to justify holding wrists or arms during typing. S2C proponents use it to justify index finger typing (which they characterize, incorrectly, as a gross motor skill) as a substitute for speech (which they characterize, correctly, as a fine motor skill).
One reason why it’s natural to implicate motor control is that difficulties here, especially in fine motor, offer an obvious explanation for lack of speech. Speech, after all, involves complex co-occurring movements of lips, tongue, jaw, and throat. Furthermore, there is a known condition, apraxia of speech, that specifically involves problems executing these kinds of oral-motor movements. Finally, it is generally those with the least speech—and therefore those with the greatest presumed problems with oral-motor control—who are most likely to be subjected to FC.
But oral-motor control problems/apraxia of speech are not the only explanations for lack of speech in autism—nor are they the most plausible.
There are, indeed, other reasons for lack of speech besides oral-motor issues. Consider deafness. Deafness is not a motor disability, but it does impede the production of speech sounds. Even after years of intensive speech-language training in how to move lips, tongue, mouth, and throat to make specific sounds, the speech of most deaf people (unless they’re assisted by technologies like cochlear implants) is largely unintelligible to all but their closest, longest-term associates.
Why do deaf people have so much trouble speaking? The issue, of course, is lack of acoustic feedback. Deaf people are unable to hear the sounds that come out of people’s mouths, including their own; they are unable to tune their speech to match that of others. It’s the obstacles to tuning in and tuning up, not motor control problems, that underlie the speech impairments in deafness.
Most autistic individuals, of course, aren’t deaf. But mounting evidence suggest that something similar is going on, particularly in severe autism. The issue is that it’s not enough to be able to hear speech sounds: you also need to pay attention to them. Consider, instead of speech sounds, bird sounds. Most of us, even those of us who live in bird-rich environments, pay little attention to bird sounds. As a result, we learn little about the details—which birds make which sounds; how bird sounds vary by time of day and by season—and spend even less time trying to imitate them.
Studies of “high-risk” infants later diagnosed with autism show diminished attention to speech sounds, difficulty integrating speech sounds with lip movements, and preferential attention to environmental sounds [1]. Reflecting this, compared to their non-autistic counterparts, these infants produce a much higher proportion of non-speech vocalizations, which strongly suggests that failing to selectively take in speech sounds results in a failure to selectively produce speech sounds [2].
The diagnostic criteria for autism, moreover, indicate that the degree to which attention to social stimuli is diminished (speech being a major component of social stimuli) correlates with the degree of autism severity.
Put together, all these factors are enough to explain the lack of speech in severe autism [3]. Not paying attention to speech sounds has similar effects to not hearing speech sounds. These effects include diminished opportunities to practice making speech sounds and tuning those sounds to the sounds made by others. More problematically, these effects also include diminished opportunities to learn language.
What all this means is that the communication problem in non-speaking autism is deeper than many of us would prefer to believe. If it were just a matter of motor control, then all that’s necessary would be finding legitimate AAC tools (no, not held-up keyboards and hovering facilitators) that bypass the motor issues. But if non-speaking reflects not listening, then the communication problem is a language problem—one that includes written language as well as spoken language [4], and language comprehension as well as language production.
Unfortunately, where autism is concerned, all the evidence suggests that non-speaking/minimally-speaking mean non-verbal/minimally-verbal.
And the only thing that makes it appear otherwise is one or another form of facilitated communication.
[1]
Dawson, G., Meltzoff, A. N., Osterling, J., Rinaldi, J., & Brown, E. (1998). Children with autism fail to orient to naturally occurring social stimuli. Journal of Autism and Developmental Disorders, 28(6), 479–485. https://doi.org/10.1023/a:1026043926488
Groen, W. B., Zwiers, M. P., van der Gaag, R. J., & Buitelaar, J. K. (2008). The phenotype and neural correlates of language in autism: an integrative review. Neuroscience and Biobehavioral Reviews, 32(8), 1416–1425. https://doi.org/10.1016/j.neubiorev.2008.05.008
Kim S. H., Paul, R, Tager-Flusberg, H., & Lord, C. (2014). Language and communication in autism. In F. Volkmar, R. Paul, S. J. Rogers, and K. A. Pelphrey (Eds.), Handbook of autism and pervasive developmental disorders (4th edition) (Vol. 1). (pp. 232-363). Wiley. https://doi.org/10.1002/9781118911389.hautc10
Lepistö, T., Kujala, T., Vanhala, R., Alku, P., Huotilainen, M., & Näätänen, R. (2005). The discrimination of and orienting to speech and non-speech sounds in children with autism. Brain Research, 1066(1-2), 147–157. https://doi.org/10.1016/j.brainres.2005.10.052
Magrelli, S., Jermann, P., Noris, B., Ansermet, F., Hentsch, F., Nadel, J., & Billard, A. (2013). Social orienting of children with autism to facial expressions and speech: a study with a wearable eye-tracker in naturalistic settings. Frontiers in Psychology, 4, 840. https://doi.org/10.3389/fpsyg.2013.00840
[2]
Guiraud, J. A., Tomalski, P., Kushnerenko, E., Ribeiro, H., Davies, K., Charman, T., Elsabbagh, M., Johnson, M. H., & BASIS Team (2012). Atypical audiovisual speech integration in infants at risk for autism. PloS One, 7(5), e36428. https://doi.org/10.1371/journal.pone.0036428
Patterson, M. L., & Werker, J. F. (1999). Matching phonetic information in lips and voice is robust in 4.5-month-old infants. Infant Behavior & Development, 22(2), 237–247. https://doi.org/10.1016/j.cognition.2008.05.009
[3] See also Shriberg, L. D., Paul, R., Black, L. M., & van Santen, J. P. (2011). The hypothesis of apraxia of speech in children with autism spectrum disorder. Journal of Autism and Developmental Disorders, 41(4), 405–426. https://doi.org/10.1007/s10803-010-1117-5
[4] Aside from words that label pictures, most written words cannot be learned in isolation from the spoken (or signed) language that occurs in the ambient environment.
