Understanding ASD Traits from a Sensory Sensitivity and Habituation Perspective

Background:

Sensory symptoms, including unusual sensory seeking, over-responsivity (SOR) and under-responsivity, are recognized as core features of Autistic Spectrum Disorder (ASD). However, their interplay with other facets of the ASD phenotype (i.e., social-communication and cognitive) is yet to be understood. The Empathizing- Systemizing theory views the autistic drive to analyze and construct systems as closely related to the unique sensory perception of individuals with ASD. Sensory evidence relies mostly upon the Sensory Profile questionnaire, which inquires about the affective response to daily stimuli with some overlap with social-communication features of ASD. Our study utilized sensory questionnaires aimed to isolate different perceptual aspects of sensory symptoms and bypass overlap with other clinical features. SOR may reflect an increased reaction towards a stimulus and/or a relatively slow sensory habituation, an overlooked aspect. Lack of Sensory habituation may contribute to the functional impairment of individuals with ASD. We hypothesize that both sensitivity and habituation play an important part in explaining specific ASD traits.

Objectives: To (1) examine the relationship between different ASD traits and sensory symptoms; and (2) determine the contribution of sensory sensitivity versus slow habituation to specific ASD traits.

Methods: Eighty typical adults rated their sensory symptoms with the Adolescent/Adult Sensory Profile (AASP), Sensory Perception Quotient (SPQ) and the Sensory Habituation Questionnaire (S-Hab-Q). Autistic traits including: social skills, communication, imagination, attention to details and attention switching, were reported via the Autism Spectrum Quotient (AQ).

Results: The AQ score showed a significant moderate correlation with the AASP/SOR score (r=.36, p=.001), with the SPQ sensitivity score (r = 0.33, p = 0.003), and S-Hab-Q score (r=.45, p=.002). Among the AQ subscales, attention to details stood out by correlating with the S-Hab-Q (r=.34, p=.024) and SPQ (r=.48, p=.001), while not with the AASP/SOR scores. Interestingly, the AQ communication and imagination subscales correlated with AASP sensory under-responsivity (r=.33, p=0.31) and seeking scores (r=-.33, p=.0.31) while not with any of the SOR scores in this study (p ≥.49). None of the sensory scores associated with the social AQ scores (p >.68).

Conclusions: Our findings significantly add to the "systemizing theory" which views SOR as the underlying cause of over-focused attention. Although "attention to details" would seem to be more associated with increased sensitivity, we found that habituation and sensitivity contributed equally. When scrutinizing other sensory aspects, we found that seeking and under responsivity correlate distinctively with communication and imagination ASD traits. These sensory symptoms may tap into developmental level rather than perceptual atypicalities. This study shows the importance of using sensory tools which measure perceptual aspects of SOR. Examining these correlations in a clinical sample of ASD and combining knowledge about sensory symptoms from questionnaire and physiological data is needed to further understand these correlations.