Olfaction in the autism spectrum

Centre d'Excellence en Troubles Envahissants du Développement de I'Université de Montréal (CETEDUM), Montréal, QC, Canada.
Perception (Impact Factor: 0.91). 07/2013; 42(3):341-55. DOI: 10.1068/p7337
Source: PubMed


The autism spectrum (AS) is characterised by enhanced perception in vision and audition, described by the enhanced perceptual functioning (EPF) model. This model predicts enhanced low-level (discrimination of psychophysical dimensions), and mid- and high-level (pattern detection and identification) perception. The EPF model is here tested for olfaction by investigating olfactory function in autistic and Asperger participants. Experiment 1 targeted higher-order olfactory processing by assessing olfactory identification in nine Asperger, ten autistic, and eleven typically developed individuals. Experiment 2 focused on low-level olfactory processing; we assessed odour detection thresholds and odour discrimination in five Asperger, five autistic, and five typically developed males. Olfactory identification was impaired in autistic participants relative to control and Asperger participants. Typical performance in low-level olfactory processing suggests that neural mechanisms involved in the perceptual phenotype of AS do not affect structures implicated in olfactory processing. Reduced olfactory identification is limited to autistic participants who displayed speech delay and may be due to a reduced facility to use verbal labels. The apparent absence of enhanced olfactory perception of AS participants distinguishes the olfactory system from the other sensory modalities and might be caused by the absence of an obligatory thalamic relay.

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Available from: Laurent Mottron, Mar 02, 2014
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    • "Besides these 2 promising scientific attempts, the few clinical and scientific reports available that characterized olfactory function in this population suggest that individuals with ASD have atypical responses to olfactory stimuli [reviewed in (Martin and Daniel, 2014), and (Schecklmann et al., 2013)], although results have not often been concordant: odor detection ability was equivalent between adults with ASD and controls in 3 studies (Suzuki, 2003; Galle et al., 2013; Tavassoli and Baron- Cohen, 2012), whereas in another study odor detection was better in ASD patients (Ashwin et al., 2014). Odor identification was impaired in 2 studies (Suzuki, 2003; Galle et al., 2013). Studies in ASD children also showed lack of consensus: Bennetto et al. (2007) reported lower odor identification ability in ASD patients than controls, whereas Dudova et al. (2011) found lower odor detection but no difference in identification between ASD children and healthy controls. "
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