Olfactory Processing in Male Children with Autism: Atypical Odor Threshold and Identification

Sensory issues are of great interest in ASD diagnosis. However, their investigation is mainly based on external observation (parent reports), with methodological limitations. Unobtrusive olfactory assessment allows studying autism neurosensoriality. Here, 20 male children with high-functioning ASD and 20 matched controls were administered a complete olfactory test battery, assessing olfactory threshold, identification and discrimination. ASD children show lower sensitivity (p = 0.041), lower identification (p = 0.014), and intact odor discrimination (p = 0.199) than controls. Comparing olfactory and clinical scores, a significant correlation was found in ASD between olfactory threshold and the CBCL social problems (p = 0.011) and aggressive behavior (p = 0.012) sub-scales. The pattern featuring peripheral hyposensitivity, high-order difficulties in odor identification and regular subcortical odor discrimination is discussed in light of hypo-priors hypothesis for autism.