Enhanced pure-tone pitch discrimination among persons with autism but not Asperger syndrome

Abstract

Persons with Autism spectrum disorders (ASD) display atypical perceptual processing in visual and auditory tasks. In vision, Bertone, Mottron, Jelenic, and Faubert (2005) found that enhanced and diminished visual processing is linked to the level of neural complexity required to process stimuli, as proposed in the neural complexity hypothesis. Based on these findings, Samson, Mottron, Jemel, Belin, and Ciocca (2006) proposed to extend the neural complexity hypothesis to the auditory modality. They hypothesized that persons with ASD should display enhanced performance for simple tones that are processed in primary auditory cortical regions, but diminished performance for complex tones that require additional processing in associative auditory regions, in comparison to typically developing individuals. To assess this hypothesis, we designed four auditory discrimination experiments targeting pitch, non-vocal and vocal timbre, and loudness. Stimuli consisted of spectro-temporally simple and complex tones. The participants were adolescents and young adults with autism, Asperger syndrome, and typical developmental histories, all with IQs in the normal range. Consistent with the neural complexity hypothesis and enhanced perceptual functioning model of ASD (Mottron, Dawson, Soulières, Hubert, & Burack, 2006), the participants with autism, but not with Asperger syndrome, displayed enhanced pitch discrimination for simple tones. However, no discrimination-thresholds differences were found between the participants with ASD and the typically developing persons across spectrally and temporally complex conditions. These findings indicate that enhanced pure-tone pitch discrimination may be a cognitive correlate of speech-delay among persons with ASD. However, auditory discrimination among this group does not appear to be directly contingent on the spectro-temporal complexity of the stimuli.

Fragile Spectral and Temporal Auditory Processing in Adolescents with Autism Spectrum Disorder and Early Language Delay

“…The majority of studies investigated more advanced pitch processing aspects like categorization, labelling, memory or disembedding, and they often used much more complex auditory stimuli or speech stimuli (e.g., Foxton et al 2003;Heaton 2003;Heaton et al 2005Heaton et al , 2008bJärvinen-Pasley and Heaton 2007;Järvinen-Pasley et al 2008a, b;Mottron et al 2000). Only three studies used a similar adaptive staircase procedure (as we did) to assess pure tone pitch processing (Bhatara et al 2013;Bonnel et al 2010;Jones et al 2009). The first psychoacoustic evidence for enhanced pitch discrimination of pure tones was provided by Bonnel et al (2003), who observed superior pitch discrimination in adolescents with autism and in adults meeting full criteria for autism but not in those with Asperger syndrome (Bonnel et al 2010).…”

“…Only three studies used a similar adaptive staircase procedure (as we did) to assess pure tone pitch processing (Bhatara et al 2013;Bonnel et al 2010;Jones et al 2009). The first psychoacoustic evidence for enhanced pitch discrimination of pure tones was provided by Bonnel et al (2003), who observed superior pitch discrimination in adolescents with autism and in adults meeting full criteria for autism but not in those with Asperger syndrome (Bonnel et al 2010). Partial support for this finding was provided by Jones et al (2009), who found no differences in frequency discrimination at the group level, but who identified a subgroup of adolescents with ASD and delayed language onset who showed exceptional frequency categorization.…”

“…One of the most prominent observations concerns the evidence for enhanced pitch perception in children on the autistic spectrum and in a subgroup of adolescents and adults with ASD, especially those with early developmental language delay and language-related difficulties (O'Connor 2012). Superior pitch processing has been established regardless of stimulus complexity (e.g., for pure tones, complex tones, contours, nonwords, words and sentences) using a variety of psychophysical tasks (e.g., identification, discrimination, categorization, memory and labeling) (e.g., Bonnel et al 2003Bonnel et al , 2010Heaton 2005;Heaton et al 2008a, b, c;Järvinen-Pasley and Heaton 2007;Jones et al 2009;O'Riordan and Passetti 2006;Stanutz et al 2014). The majority of research using event-related potentials (ERP) also revealed enhanced neural detection of frequency changes in ASD at the pre-attentive level (using mismatch negativity or MMN) (e.g., Ferri et al 2003;Gomot et al 2002;Kujala et al 2007; but see Jansson-Verkasalo et al 2003; see Haesen et al 2011 for an extensive recent review of the psychophysical and electrophysiological literature on auditory processing in ASD).…”

“…Tenmonth-olds, however, can generalize across speaker sex, suggesting that with development infants can more readily ignore irrelevant absolute pitch cues in speech and consequently build up more abstract higher-order speech representations (Houston et al 1998). Against this background, it should not be too surprising that a substantial proportion of individuals with ASD shows early developmental language delay as well as broader linguistic impairments later in life, and that these are exactly the individuals who are most prone to present superior acoustic processing of pitch (e.g., Bonnel et al 2010;Heaton et al 2008c;Jones et al 2009). …”

The Relationship Between Auditory Processing and Restricted, Repetitive Behaviors in Adults with Autism Spectrum Disorders

“…Evidence for enhanced frequency discrimination ability of isolated pure tone stimuli has been found in children with ASD (Bonnel et al, 2003;Heaton, et al, 2008;O'Riordan and Passetti, 2006) and in adults with autism (although not in adults with Asperger's syndrome) in combined four-interval with two-forced choice (2IFC) frequency discrimination tasks (Bonnel et al, 2010). Furthermore, a similar pattern of ability has been observed also at neural levels in electrophysiological studies investigating neural response to changes of frequency in individuals with ASD, at the pre-attentive level (Ferri et al, 2003;Gomot et al, 2011;Gomot, Giard, Adrien, Barthelemy, and Bruneau, 2002;Kujala et al, 2010;Lepistö et al, 2008;.…”