The Sensory Perception Quotient: Validation In Adults with and without Autism Spectrum Conditions

Background:  Anecdotal reports suggest sensory differences in autism spectrum conditions (ASC) (Grandin, 1996; Chamak et al, 2008). In addition questionnaire based studies report sensory issues in ASC (Leekam et al., 2007, Klintwall et al., 2010). The most widely used sensory questionnaire, the Sensory Profile, shows differences in over 90% of children and adults with ASC (Kientz &Dunn, 1997). However, the Sensory Profile evaluates the behavioural response towards sensory experiences and there is a need for an adult questionnaire investigating basic sensory sensitivity towards stimuli. 

Objectives:  (1) To report data from a new measure, the Sensory Perception Quotient (SPQ), which assesses basic sensory sensitivity. (2) To investigate if adults with ASC report sensory differences on the SPQ. (3) To examine if reported sensory sensitivities are linked to autistic traits. 

Methods:  545 adults with (n=275) and without (n=262) ASC participated in an online study. Participants were asked to fill in the SPQ, as well as the Sensory Over-responsivity Inventory (SenSOR) (Schoen & Miller, 2009). The SenSOR was developed to evaluate sensory processing disorder, or sensory over-responsivity (Schoen & Miller, 2009). The SenSOR measures how many sensations are experienced as aversive (e.g. labels in clothes). Compared to the SenSOR the SPQ investigates basic sensory perception rather than the emotional response towards it. The SenSOR was included to examine the validity of the SPQ. An online adaptation of the Raven matrices was used to measure intellectual ability (IQ) in both groups. Lastly, autistic traits were measured using the Autism Spectrum Quotient (AQ; Baron-Cohen et al., 2001). 

Results:  The groups did not differ in terms of IQ or age (p>.05). Items of the SPQ were reduced using a principal component analysis. Split half-reliabilities were calculated and showed good item reliability (r=.81). Adults with ASC reported more sensory sensitivity on the SPQ compared to controls (p<.001). The SPQ score was significantly correlated with the SenSOR score (r= .49, p<.001). Finally, the SPQ score was positively correlated to the AQ across groups (r=.33, p<.001) and within the ASC group (r=.34, p<.001) and control group (r=.24, p<.001).

Conclusions: The Sensory Perception Quotient (SPQ) showed good split-half reliability and validity. In addition the SPQ discriminated between adults with and without ASC. Adults with ASC reported more sensitivity to sensory stimuli on both the SPQ and the SenSOR. Lastly, greater sensory sensitivity was associated with more autistic traits. Sensory issues in adults with ASC have been understudied; the SPQ provides the first questionnaire to measure an individual’s sensory sensitivity. This quick and reliable tool can be of great value in future projects studying this important topic.