# Cross-cultural adaptation, reliability, and validity of a Chinese version of the swallowing impairment score

## TL;DR

This study adapts and validates a Chinese version of a questionnaire to assess swallowing difficulties after thyroidectomy, showing it is reliable and effective.

## Contribution

The study provides a culturally adapted and validated Mandarin Chinese version of the Swallowing Impairment Score (SIS-6) questionnaire.

## Key findings

- The Chinese version of SIS-6 showed no floor or ceiling effects and had a Cronbach's α coefficient of 0.790.
- The item-level content validity index ranged from 0.880 to 1, and the confirmatory factor analysis supported a two-factor structure.
- The scale demonstrated satisfactory psychometric properties despite gender imbalance in the sample.

## Abstract

The impact of thyroidectomy on swallowing is prevalent. Difficulties in swallowing can lead to malnutrition, destress and a decline in quality of life. The Swallowing Impairment Score (SIS-6) is a uniquely self-evaluation questionnaire aimed at comprehensively assessing the swallowing impairment status in patients after thyroidectomy. However, there is currently no Chinese version available for use among Chinese populations. The objective of this research is to culturally modify the SIS-6 to a Mandarin Chinese version and validate its psychometric features.

Initially, the SIS-6 was translated and refined; 30 patients who underwent thyroidectomy were enrolled for the cognitive testing. Subsequently, a total of 468 patients who had undergone thyroidectomy were enrolled to evaluate the psychometric properties of the Chinese version.

The Chinese version of SIS-6 was developed through translation and cultural adaptation processes. No floor or ceiling effects were observed. The scale-level Cronbach's α coefficient was 0.790 with each item ranging from 0.404 to 0.665. The scale-level intra-class correlation coefficient was 0.889 with each item ranging from 0.594 to 0.920. The item-level content validity index ranging from 0.880 to 1, with scale-level content validity index of 0.910. The confirmatory factor analysis verified the two-factor structure of the Chinese version of SIS-6 with factor loadings for each item ranging from 0.530 to 0.810.

Although the Mandarin Chinese version of SIS-6 exhibited gender imbalance within its sample size and lacked a cut-off value, it demonstrated satisfactory psychometric properties overall and served as an effective and reliable tool for assessing swallowing difficulties in patients after thyroidectomy.