Habituation of auditory responses in young autistic and neurotypical children.
Autistic toddlers’ brains stay stuck on repeated sounds, yet this lab measure does not tell us how they will act at home or school.
01Research in Context
What this study did
Dwyer et al. (2023) played the same loud and soft tones to toddlers and preschoolers.
Some kids had autism. Some were neurotypical.
The team measured tiny brain waves while the sounds repeated to see how fast each child’s brain tuned them out.
What they found
Autistic children’s N2 wave stayed big even after many tones.
Neurotypical children’s N2 wave shrank, showing normal habituation.
Parent reports of everyday sound trouble did not match the N2 result.
How this fits with other research
Anthony et al. (2020) saw the same habituation drop, but in the earlier P1 wave.
Together, the two studies show autistic brains keep responding to sounds longer at two different processing stages.
Tavassoli et al. (2012) found intact smell adaptation in autistic adults.
The nose data seem opposite, but the tasks, senses, and ages differ, so both can be true.
Why it matters
You can’t assume a child who covers his ears in the cafeteria will show odd brain waves in clinic, or vice versa.
Use both parent interviews and direct probes when you assess sensory needs.
If a child still startles to the same warning beep, try spacing sounds further apart or adding visual cues instead of just lowering volume.
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02At a glance
03Original abstract
Prior studies suggest that habituation of sensory responses is reduced in autism and that diminished habituation could be related to atypical autistic sensory experiences, for example, by causing brain responses to aversive stimuli to remain strong over time instead of being suppressed. While many prior studies exploring habituation in autism have repeatedly presented identical stimuli, other studies suggest group differences can still be observed in habituation to intermittent stimuli. The present study explored habituation of electrophysiological responses to auditory complex tones of varying intensities (50-80 dB SPL), presented passively in an interleaved manner, in a well-characterized sample of 127 autistic (MDQ = 65.41, SD = 20.54) and 79 typically developing (MDQ = 106.02, SD = 11.50) children between 2 and 5 years old. Habituation was quantified as changes in the amplitudes of single-trial responses to tones of each intensity over the course of the experiment. Habituation of the auditory N2 response was substantially reduced in autistic participants as compared to typically developing controls, although diagnostic groups did not clearly differ in habituation of the P1 response. Interestingly, the P1 habituated less to loud 80 dB sounds than softer sounds, whereas the N2 habituated less to soft 50 dB sounds than louder sounds. No associations were found between electrophysiological habituation and cognitive ability or participants' caregiver-reported sound tolerance (Sensory Profile Hyperacusis Index). The results present study results extend prior research suggesting habituation of certain sensory responses is reduced in autism; however, they also suggest that habituation differences observed using this study's paradigm might not be a primary driver of autistic participants' real-world sound intolerance.
Autism research : official journal of the International Society for Autism Research, 2023 · doi:10.1097/AUD.0000000000001005