Psychometric Validation and Refinement of the Interoception Sensory Questionnaire (ISQ) in Adolescents and Adults on the Autism Spectrum
Background: Individuals on the autism spectrum are reported to display alterations in interoception, the sense of the internal state of the body. The Interoception Sensory Questionnaire (ISQ) is a 20-item self-report measure of interoception specifically intended to measure this construct in autistic people. Thus far, the ISQ has not undergone psychometric evaluation in a large sample.
Methods: Using confirmatory factor analysis, we evaluated the latent structure of the ISQ in a large online sample of adults on the autism spectrum and found that the unidimensional model fit the data poorly. Using misspecification analysis to identify areas of local misfit and item response theory to investigate the appropriateness of the 7-point response scale, we removed redundant items and collapsed the response options to put forth a novel 8-item, 5-response choice ISQ.
Results: The revised, 5-response choice ISQ (ISQ-8) showed much improved fit while maintaining high internal reliability. Differential item functioning (DIF) analyses indicated that the items ISQ-8 were answered in comparable ways by autistic adolescents and adults and across multiple other sociodemographic groups.
Limitations: Our results were limited by the fact that we did not collect data for typically developing controls, preventing the analysis of DIF by diagnostic status. Additionally, while this study proposes a new 5-response scale for the ISQ-8, our data were not collected using this method, and thus the psychometric properties for the revised version of this instrument require further investigation.
Conclusion: The ISQ-8 shows promise as a reliable and valid measure of interoception in adolescents and adults on the autism spectrum, but additional work is needed to examine its psychometrics in this population. A free online score calculator has been created to facilitate the use of ISQ-8 latent trait scores for further studies of autistic adolescents and adults (available at https://asdmeasures.shinyapps.io/ISQ_score/).
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Posted 29 Dec, 2020
Received 18 Jan, 2021
On 17 Jan, 2021
On 06 Jan, 2021
On 03 Jan, 2021
Invitations sent on 28 Dec, 2020
On 25 Dec, 2020
On 25 Dec, 2020
On 24 Dec, 2020
On 21 Dec, 2020
Psychometric Validation and Refinement of the Interoception Sensory Questionnaire (ISQ) in Adolescents and Adults on the Autism Spectrum
Posted 29 Dec, 2020
Received 18 Jan, 2021
On 17 Jan, 2021
On 06 Jan, 2021
On 03 Jan, 2021
Invitations sent on 28 Dec, 2020
On 25 Dec, 2020
On 25 Dec, 2020
On 24 Dec, 2020
On 21 Dec, 2020
Background: Individuals on the autism spectrum are reported to display alterations in interoception, the sense of the internal state of the body. The Interoception Sensory Questionnaire (ISQ) is a 20-item self-report measure of interoception specifically intended to measure this construct in autistic people. Thus far, the ISQ has not undergone psychometric evaluation in a large sample.
Methods: Using confirmatory factor analysis, we evaluated the latent structure of the ISQ in a large online sample of adults on the autism spectrum and found that the unidimensional model fit the data poorly. Using misspecification analysis to identify areas of local misfit and item response theory to investigate the appropriateness of the 7-point response scale, we removed redundant items and collapsed the response options to put forth a novel 8-item, 5-response choice ISQ.
Results: The revised, 5-response choice ISQ (ISQ-8) showed much improved fit while maintaining high internal reliability. Differential item functioning (DIF) analyses indicated that the items ISQ-8 were answered in comparable ways by autistic adolescents and adults and across multiple other sociodemographic groups.
Limitations: Our results were limited by the fact that we did not collect data for typically developing controls, preventing the analysis of DIF by diagnostic status. Additionally, while this study proposes a new 5-response scale for the ISQ-8, our data were not collected using this method, and thus the psychometric properties for the revised version of this instrument require further investigation.
Conclusion: The ISQ-8 shows promise as a reliable and valid measure of interoception in adolescents and adults on the autism spectrum, but additional work is needed to examine its psychometrics in this population. A free online score calculator has been created to facilitate the use of ISQ-8 latent trait scores for further studies of autistic adolescents and adults (available at https://asdmeasures.shinyapps.io/ISQ_score/).