Untangling Self-Reported Interoceptive Attention and Accuracy: Evidence from the European Portuguese Validation of the Body Perception Questionnaire and the Interoceptive Accuracy Scale

Objectives: To explore the factor structure and psychometric properties of the European Portuguese versions of the Interoceptive Accuracy Scale (IAS) and the Body Perception Questionnaire (BPQ) - Body Awareness and Autonomic Reactivity; to examine the association between self-reported interoceptive attention and accuracy (BPQ Body Awareness and IAS, respectively). Method: A community-sample (n=515) completed an online survey comprising the IAS, BPQ, and Toronto Alexithymia Scale. Factor structure analyses followed a comprehensive pipeline (parallel analysis and EFA, to establish the number of factors and item loadings; CFA and ESEM, to compare different factor structures). Additional psychometric analyses included internal consistency and test-retest analyses. Correlational analyses examined the associations between alexithymia, interoceptive attention and accuracy. Polynomial regression and two-lines testing investigated the quadratic association between IAS and BPQ. Results: Parallel-analysis indicated a one-factor solution for BPQ Body Awareness. For IAS and BPQ Autonomic Reactivity, bifactor ESEM models were retained. Ancillary measures revealed that both scales were mainly unidimensional and presented reliable total scores. All scales displayed excellent internal consistency, although test-rest reliability was modest. IAS and BPQ Body Awareness were moderately correlated and further displayed a quadratic U-shaped association. Alexithymia was negatively correlated with IAS and unassociated with BPQ Body Awareness. Conclusions: The European Portuguese IAS and BPQ displayed good psychometric properties and can thus be used within clinical and research settings. These questionnaires were differentially related to alexithymia, suggesting that interoceptive attention and accuracy may be dissociated using self-reports, although future research should further examine their linear vs. quadratic association.