# Test–Retest Reliability and Convergent Validity of Two Scoring Versions of the Spinal Appearance Questionnaire Against Radiographic Measurements and Established Quality of Life Questionnaires in Adolescents with Idiopathic Scoliosis

## TL;DR

A new version of the Spinal Appearance Questionnaire (SAQv1.1) shows better reliability and fewer issues with ceiling effects compared to the original SAQ in adolescents with scoliosis.

## Contribution

The study introduces and validates an improved version of the SAQ with better reliability and fewer measurement limitations.

## Key findings

- SAQv1.1 has strong test–retest reliability and convergent validity with established measures like the SRS-22r and Cobb angle.
- SAQv1.1 has fewer ceiling effects compared to the original SAQ, making it more suitable for detecting treatment effects in mild to moderate scoliosis.
- The SAQv1.1 Total and Appearance scores show low ceiling effects (≤5%), improving its usefulness in clinical and research settings.

## Abstract

What are the main findings?
The SAQv1.1 test–retest reliability meets standards for research and individual use.All SAQv1.1 domains showed convergent validity with the SRS-22r and the Cobb angle and fewer ceiling effects compared to the original SAQ scores.

The SAQv1.1 test–retest reliability meets standards for research and individual use.

All SAQv1.1 domains showed convergent validity with the SRS-22r and the Cobb angle and fewer ceiling effects compared to the original SAQ scores.

What are the implications of the main findings?
The SAQv1.1 is recommended over the original SAQ in clinical and research settings.With smaller measurement error and fewer ceiling effects, the SAQv1.1 may help detect the effects of treatments for patients with small and moderate scoliosis curves.

The SAQv1.1 is recommended over the original SAQ in clinical and research settings.

With smaller measurement error and fewer ceiling effects, the SAQv1.1 may help detect the effects of treatments for patients with small and moderate scoliosis curves.

Background/Objectives: The Spinal Appearance Questionnaire (SAQ) assesses the self-perception of appearance of adolescents with idiopathic scoliosis (AIS). Due to originally scoring too many domains and producing prevalent ceiling effects when treated conservatively, the SAQv1.1, has been introduced. This study aimed to compare the test–retest reliability, convergent validity, and ceiling and floor effects of the two versions of the SAQ in patients with AIS. Methods: Conservatively treated females with AIS, aged 10–18 years old, were consecutively recruited from a scoliosis clinic. The Scoliosis Research Society-22 refined (SRS-22r), SAQ, and SAQv1.1 were collected, in English, with radiographic measurements (Cobb angle, Coronal Balance, and Vertebral Rotations). Nine domain scores were obtained from the original SAQ. Appearance, Expectations, and Total scores were calculated for SAQ v.1.1. Questionnaires were re-administered electronically after one week. Results: One hundred females, aged 13.9 ± 1.8 years with curve angles of 28.8° ± 13.9°, were included. The test–retest reliability for SAQ varied between domains (ICC3,1 = 0.72 to 0.94). The Total, Appearance, and Expectation ICCs3,1 for the SAQv1.1 were 0.92, 0.94, and 0.86, respectively. Convergent validity was demonstrated between seven SAQ domains and the SRS-22r Total and Cobb angle (|r| = 0.32 to 0.59). The SAQv1.1 Total correlated with the SRS-22r Total (r = −0.50) and with the Cobb angle (r = 0.56). All SAQ domains presented ceiling (Curve = 11% to Kyphosis = 68%) and floor effects (Chest = 8% and Waist = 4%). The SAQv1.1 Total and Appearance had low ceiling effects (≤5%), while Expectations presented both ceiling (14%) and floor effects (10%). Conclusions: The SAQv1.1 is recommended because of its stronger reliability, superior convergent validity, and fewer ceiling and floor effects in AIS.