Direct Observational and Biological Measurement of Reactivity to Sensory Stimuli for Use with and without Developmental Disabilities

Abstract

Given the inclusion of sensory reactivity as a diagnostic criterion for autism spectrum disorder (ASD) and the theorized etiological role of sensory reactivity in the development of autism, adequate sensory measures of sensory reactivity in autism, including measures extending to use in infancy, are needed. Adequate sensory measurement relies on the use of multiple methods of measurement. A scoping review of direct observational and biological measures of responses to sensory stimuli was conducted to identify plausible direct observational and biological measures of sensory reactivity for use with autistic samples. A direct observational measure of sensory reactivity was identified in the scoping review (a modified quantitative sensory testing approach) and implemented in two empirical investigations with different samples. The modified quantitative sensory testing approach was undertaken with a sample of children with and without autism (n=45, including eight autistic children) to investigate differences in tactile reactivity between children with and without autism. The modified quantitative sensory testing approach was then undertaken with a sample of typically developing children (n=34) to explore the relationship between subjective experience of tactile stimuli and behaviorally observed tactile reactivity. Through the scoping review, 111 articles reporting the use of a direct observational or biological sensory measure were identified, including 53 articles describing the use of behavioral measures of sensory reactivity, 18 articles describing the use of peripheral nervous system physiology measures of sensory reactivity, 47 articles describing the use of central nervous system physiology measures of sensory reactivity, and eight articles describing the use of circuits of sensory reactivity. The use of direct observational measure, the modified Quantitative Sensory Test (mQST), identified differences in tactile reactivity to four tactile stimuli (light touch, pinprick, the last five seconds of the repeated von Frey, and heat), such that autistic children tended to demonstrate greater behavioral reactivity in response to these stimuli. The use of the mQST with typically developing children to interrogate the subjective experience of the mQST stimuli via self-report yielded negligible to weak correlations between subjective experience and direct observation of behavioral reactivity in response to the tactile stimuli but did, however, yield validity evidence for the use of the mQST in typically developing children. Overall, a wide variety of direct observational and biological sensory measures are available for use in autism research, with the potential to shed light on underlying mechanisms explaining differences in overt sensory behaviors.