Difficulty with Speech Perception in the Background of Noise in Children with Autism Spectrum Disorders Is Not Related to Their Level of Intelligence

Children with autism spectrum disorders (ASD) have more difficulty than typically developing peers understanding speech in noisy environments. Underlying this difficulty may be their decreased noise tolerance and/or difficulty integrating fragments of speech over temporal gaps, which usually present in noise. We investigated the role of these factors in children with ASD with a wide range of cognitive abilities. The sample consisted of 42 children with ASD and 38 typically developing children aged 7–12 years. The participants were asked to repeat two-syllable words presented in the background of noise. Two types of masking were used: stationary noise and amplitude-modulated noise. Intelligence was assessed using the Kaufman Assessment Battery for Children (KABC-II). The results show that children with ASD are worse at recognizing words in stationary noise than typically developing children. Even after adjusting for performance in stationary noise, the presence of gaps in the amplitude-modulated noise improved their performance to a lesser degree than in typically developing children (F(1,75)=18.57, p<0.001). Neither performance in stationary noise nor the ability to benefit from gaps in amplitude-modulated noise correlated with IQ in children with ASD (Spearman's coefficients, all p>0.80). We concluded that difficulties with speech perception in noise in children with ASD do not depend on the level of their cognitive abilities and are associated with two separate factors: low noise tolerance and poor temporal integration of phonemes into the auditory word form.