SLPCohortResearch in developmental disabilities2024

Acoustic features of vocalizations in typically developing and autistic infants in the first year.

D Kimbrough Oller, Edina R Bene, Hyunjoo Yoo and 8 others

PMID 39413560

WHAT IT FOUND

Infants later diagnosed with autism produced cries, whimpers, and protophones that sounded acoustically identical to typically developing infants.

However, unlike typically developing infants, those with autism did not adjust their vocal pitch or duration in response to caregiver speech.

Key findings

01Acoustic features (duration, amplitude, pitch) of infant vocalizations showed no significant differences between typically developing infants, those with autism, and those with other developmental disabilities.

02Typically developing infants adjusted their vocalizations in response to infant-directed speech by producing shorter protophones with higher pitch and amplitude.

03Infants with autism did not show significant acoustic adjustments to infant-directed speech in any of the tested comparisons.

STILL TO COME

How it was doneWhat they foundWhat it means for SLPs

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What it does not show

The study was underpowered to detect subtle differences in specific subgroups, such as infants with autism who also had language delays. The amount of infant-directed speech in the 'high' condition was relatively low compared to face-to-face laboratory interactions, which may have minimized the observed group differences in vocal responsiveness. Automated pitch measurement was affected by background noise and other voices, requiring manual correction that may have introduced bias. The sample was recruited from a 'sibling study' where infants had an older sibling with autism, which may limit generalizability to the broader population of infants with autism.

Declared interests

The authors declare no conflicts of interest. Funding details are not explicitly stated in the provided text.

The easy way to misread this

Do not assume that acoustic features of cries or early vocalizations are diagnostic for autism. This study found no difference in the sound of vocalizations between groups. The difference was in how the infants reacted to social input, not in the baseline quality of their voice.

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