Responses in left inferior frontal gyrus are altered for speech‐in‐noise processing, but not for clear speech in autism

Introduction: Autistic individuals often have difficulties with recognizing what another person is saying in noisy conditions such as in a crowded classroom or a restaurant. The underlying neural mechanisms of this speech perception difficulty are unclear. In typically developed individuals, three cerebral cortex regions are particularly related to speech-in-noise perception: the left inferior frontal gyrus (IFG), the right insula, and the left inferior parietal lobule (IPL). Here, we tested whether responses in these cerebral cortex regions are altered in speech-in-noise perception in autism.Methods: Seventeen autistic adults and 17 typically developed controls (matched pairwise on age, sex, and IQ) performed an auditory-only speech recognition task during functional magnetic resonance imaging (fMRI). Speech was presented either with noise (noise condition) or without noise (no noise condition, i.e., clear speech).Results: In the left IFG, blood-oxygenation-level-dependent (BOLD) responses were higher in the control compared to the autism group for recognizing speech-in-noise compared to clear speech. For this contrast, both groups had similar response magnitudes in the right insula and left IPL. Additionally, we replicated previous findings that BOLD responses in speech-related and auditory brain regions (including bilateral superior temporal sulcus and Heschl's gyrus) for clear speech were similar in both groups and that voice identity recognition was impaired for clear and noisy speech in autism.Discussion: Our findings show that in autism, the processing of speech is particularly reduced under noisy conditions in the left IFG-a dysfunction that might be important in explaining restricted speech comprehension in noisy environments

Altered processing of communication signals in the subcortical auditory sensory pathway in autism

Autism spectrum disorder (ASD) is characterised by social communication difficulties. These difficulties have been mainly explained by cognitive, motivational, and emotional alterations in ASD. The communication difficulties could, however, also be associated with altered sensory processing of communication signals. Here, we assessed the functional integrity of auditory sensory pathway nuclei in ASD in three independent functional magnetic resonance imaging experiments. We focused on two aspects of auditory communication that are impaired in ASD: voice identity perception, and recognising speech-in-noise. We found reduced processing in adults with ASD as compared to typically developed control groups (pairwise matched on sex, age, and full-scale IQ) in the central midbrain structure of the auditory pathway (inferior colliculus [IC]). The right IC responded less in the ASD as compared to the control group for voice identity, in contrast to speech recognition. The right IC also responded less in the ASD as compared to the control group when passively listening to vocal in contrast to non-vocal sounds. Within the control group, the left and right IC responded more when recognising speech-in-noise as compared to when recognising speech without additional noise. In the ASD group, this was only the case in the left, but not the right IC. The results show that communication signal processing in ASD is associated with reduced subcortical sensory functioning in the midbrain. The results highlight the importance of considering sensory processing alterations in explaining communication difficulties, which are at the core of ASD

Effects of Unexpected Chords and of Performer's Expression on Brain Responses and Electrodermal Activity

BACKGROUND: There is lack of neuroscientific studies investigating music processing with naturalistic stimuli, and brain responses to real music are, thus, largely unknown. METHODOLOGY/PRINCIPAL FINDINGS: This study investigates event-related brain potentials (ERPs), skin conductance responses (SCRs) and heart rate (HR) elicited by unexpected chords of piano sonatas as they were originally arranged by composers, and as they were played by professional pianists. From the musical excerpts played by the pianists (with emotional expression), we also created versions without variations in tempo and loudness (without musical expression) to investigate effects of musical expression on ERPs and SCRs. Compared to expected chords, unexpected chords elicited an early right anterior negativity (ERAN, reflecting music-syntactic processing) and an N5 (reflecting processing of meaning information) in the ERPs, as well as clear changes in the SCRs (reflecting that unexpected chords also elicited emotional responses). The ERAN was not influenced by emotional expression, whereas N5 potentials elicited by chords in general (regardless of their chord function) differed between the expressive and the non-expressive condition. CONCLUSIONS/SIGNIFICANCE: These results show that the neural mechanisms of music-syntactic processing operate independently of the emotional qualities of a stimulus, justifying the use of stimuli without emotional expression to investigate the cognitive processing of musical structure. Moreover, the data indicate that musical expression affects the neural mechanisms underlying the processing of musical meaning. Our data are the first to reveal influences of musical performance on ERPs and SCRs, and to show physiological responses to unexpected chords in naturalistic music

The relation between vocal pitch and vocal emotion recognition abilities in people with autism spectrum disorder and typical development

We tested the relation between vocal emotion and vocal pitch perception abilities in adults with high-functioning autism spectrum disorder (ASD) and pairwise matched adults with typical development. The ASD group had impaired vocal but typical non-vocal pitch and vocal timbre perception abilities. The ASD group showed less accurate vocal emotion perception than the comparison group and vocal emotion perception abilities were correlated with traits and symptoms associated with ASD. Vocal pitch and vocal emotion perception abilities were significantly correlated in the comparison group only. Our results suggest that vocal emotion recognition difficulties in ASD might not only be based on difficulties with complex social tasks, but also on difficulties with processing of basic sensory features, such as vocal pitch

Brief report: Speech-in-noise recognition and the relation to vocal pitch perception in adults with autism spectrum disorder and typical development

We tested the ability to recognise speech-in-noise and its relation to the ability to discriminate vocal pitch in adults with high-functioning autism spectrum disorder (ASD) and typically developed adults (matched pairwise on age, sex, and IQ). Typically developed individuals understood speech in higher noise levels as compared to the ASD group. Within the control group but not within the ASD group, better speech-in-noise recognition abilities were significantly correlated with better vocal pitch discrimination abilities. Our results show that speech-in-noise recognition is restricted in people with ASD. We speculate that perceptual impairments such as difficulties in vocal pitch perception might be relevant in explaining these difficulties in ASD