Speech-in-noise Perception in High-functioning Individuals with Autism or Asperger’s Syndrome

Jose´ I. Alcantara(1), Emma J.L. Weisblatt(2), Brian C.J. Moore(1),
and Patrick F. Bolton(2)
1Department of Experimental Psychology, University of Cambridge, UK;
2Department of Psychiatry, Developmental Psychiatry Section, University of Cambridge, UK

Abstract: Journal of Child Psychology and Psychiatry 45:6 (2004), pp 1107–1114

Findings

Children and adults with high-functioning autism (HFA) or Asperger’s syndrome (AS) commonly report difficulties understanding others’ speech in surroundings where there is background noise or speech. Alcantra and his colleagues performed this study to verify the validity of these reports, to quantify the difficulties these individual have in hearing others, and to better understand why this occurs. They measured speech reception thresholds (SRTs), defined as speech-to-noise ratio at which approximately 50% of the speech is recognized, in 11 individuals with HFA/AS (average age, 21 years) and 9 age-matched, normal-hearing control individuals (average age, 19 years). Inside a chamber designed to generate measurable background noise or speech, individuals listened tosentences of a British male speaker that also had four different types of background sounds. The SRTs for the HFA/AS group were worse than controls, meaning those with HFA/AS had a more difficult time identifying the voice with different background noises than the controls. Specifically, when the background noises had “dips” or pauses in them, as does speech, controls were able to more easily recognize the voice than those with HFA/AS. Expressed in another way, to fully hear and recognize the voice, the HFA/AS group required a higher signal-to-noise ratio whenever there were dips in the background sound,

Conclusions

The results suggest that the problems commonly reported by autistic individuals of understanding speech when there is background noise are real and quantifiable. This is likely because their ability to obtain information about the speech present during the spectral and temporal dips in the background is reduced from a failure to fully integrate information in the brain from glimpses of the voice during temporary dips in the background noise.