Validation and Factor Structure Analysis of the Polish Version of the Somatosensory Amplification Scale (SSAS-PL) in Clinical and Non-Clinical Samples

TL;DR

This study validated a Polish version of a scale measuring somatosensory amplification, confirming its reliability and usefulness in both clinical and non-clinical groups.

Contribution

The study provides a validated Polish version of the SSAS with confirmed psychometric properties and cross-group measurement invariance.

Findings

The SSAS-PL showed good internal consistency after removing one item.

A one-factor structure best fit the data and was theoretically interpretable.

The scale demonstrated convergent and discriminant validity across clinical and non-clinical groups.

Abstract

Objectives: The aim of this study was to validate the Polish version of the Somatosensory Amplification Scale (SSAS-PL) and examine its psychometric properties in clinical and non-clinical samples. Methods: The study included 1128 participants (711 healthy adults, 194 cardiac patients, 223 psychiatric patients). The analyses were categorized into exploratory and confirmatory phases. Exploratory analyses were conducted on a randomly selected sample that comprised 60% of the study participants (training sample) to estimate the reliability (Cronbach’s alpha) and factorial validity (EFA with varimax rotation). Confirmatory analyses were performed on an independent (test) sample that represented 40% of the total sample size to facilitate the cross-validation of the factor structure (CFA) and to assess the convergent and discriminant validities (using the HTMT method) in relation to health anxiety (SHAI) and psychopathological symptoms (KOFF-58). Additionally, measurement invariance was examined with respect to gender (female vs. male) and health status (healthy vs. clinical). Results: The SSAS-PL demonstrated good internal consistency (α = 0.75–0.78) after removing item 1. A one-factor structure showed the best fit and theoretical interpretability. The measurement invariance was supported across clinical groups. The SSAS-PL showed convergent validity with the measures of somatic symptoms, anxiety, and health anxiety. It demonstrated discriminant validity from other psychopathology measures. Conclusions: The SSAS-PL was a reliable and valid measure of somatosensory amplification in the Polish population. Its unidimensional structure aligned with most cross-cultural adaptations. The scale may be useful for assessing somatosensory amplification in both research and clinical settings in Poland. Further research on its utility in specific clinical populations is warranted.

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