Preservation of categorical perception for speech in autism with and without speech onset delay.
Verbal autistic adults label speech sounds like everyone else, but noise and new speakers can still trip them up.
01Research in Context
What this study did
Chiodo et al. (2019) asked whether verbal autistic adults hear speech sounds the same way neurotypical adults do. They split adults with autism into two groups: those who started talking on time and those who had early speech delay. Everyone listened to computer-made speech that slid from 'ba' to 'pa'. The task was simple: press a button when the sound flipped category.
What they found
Both autistic groups drew the boundary at the same spot as matched controls. There was no 'fuzzy' hearing and no super-sharp hearing either. The authors conclude that basic speech-category perception is intact in verbal autistic adults.
How this fits with other research
Alispahic et al. (2022) used the same adult population and also found normal phoneme categories. But when the talker changed mid-test, autistic listeners did not retune their boundaries. The intact static categories in Chiodo et al. (2019) may hide a flexibility gap you will see in real conversations.
Ruiz Callejo et al. (2023) tested younger autistic teens with and without early language delay. They found clear speech-in-noise deficits, especially when other voices competed. Liliane’s null result in quiet conditions does not rule out problems when noise enters the room.
Boets et al. (2015) looked at even younger teens with early delay and found weak basic pitch and gap detection. Together the papers draw a line: low-level hearing can be fragile, yet higher-level speech categories still look typical in adulthood.
Why it matters
If an adult client understands words in your clinic but keeps asking 'What?' at the grocery store, do not assume global language delay. Check auditory discrimination in noise and practice retuning to new speakers. Use clear ear-level instructions, then fade to natural voices. The ears sort sounds fine; the challenge is keeping up when the world gets loud or the talker changes.
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02At a glance
03Original abstract
Recent accounts of autistic perception, including Bayesian accounts, hypothesize a reduced influence of prior knowledge on perception across different domains in the autism spectrum (AS). The purpose of this study was to investigate the influence of prior linguistic knowledge, in the form of phonemic categorical knowledge, on speech perception in adults with AS condition. As phonemic categorical knowledge is shaped by language experience and abilities, we furthermore distinguished AS participants with (AS-SOD) or without a history of speech onset delay (AS-noSOD); the control group comprises typical individuals matched for age, nonverbal intelligence, and reading abilities. We also controlled for the influence of auditory-verbal short-term retention capacities by administering word list and nonword list repetition tasks. We did not observe any reduced influence of prior phonemic knowledge on the perception of speech stimuli nor did we observed any increased perceptual abilities for atypical variants of speech stimuli or nonspeech auditory stimuli, either between the two autistic groups or relative to the control group. Short-term memory abilities appeared to be superior in the AS-noSOD group relative to the AS-SOD and control groups, but this strength could be accounted for by their higher vocabulary knowledge. The preservation of categorical perception in verbal autistic adults observed in this study challenges models claiming a reduced influence of prior knowledge on perception across domains in the AS. Autism Res 2019. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: A reduced influence of prior knowledge has been considered to characterize perceptual abilities in people with autism. In this article, we examine this claim by assessing nonlinguistic and linguistic auditory perception abilities in adults with autism, and by further distinguishing between autism with or without a history of delayed language development. We did not observe any reduced influence of prior language knowledge on the perception of speech stimuli nor did we observe any increased perceptual abilities for atypical variants of speech stimuli or nonspeech auditory stimuli, and this relative to a control group matched on age, nonverbal intellectual efficiency, and reading abilities. Our results challenge models claiming a reduced influence of prior knowledge on perception across domains in the AS.
Autism research : official journal of the International Society for Autism Research, 2019 · doi:10.1002/aur.2134