Validation and Psychometric Properties of the German Version of the SWAL-QOL

Abstract

The SWAL-QOL questionnaire is a common tool for evaluating patients' dysphagia-specific quality of life. A validated German version is not available. This study aimed to establish a German version of the SWAL-QOL (G-SWAL-QOL) using a standardized translation procedure and to systematically evaluate its psychometric properties. The original SWAL-QOL was translated into German following international translation guidelines. A pilot study (45 subjects) confirmed comprehensibility of the G-SWAL-QOL. A consecutive series of 158 subjects (103 patients with dysphagia; 55 healthy controls) was then recruited to assess validity and reliability of the G-SWAL-QOL. Construct validity was analyzed through a correlation analysis with both (i) the Anderson Dysphagia Inventory (ADI-D) and (ii) the Short Form 36 (SF-36). Internal consistency and test-retest reliability were evaluated to determine reliability. All questions of the G-SWAL-QOL were comprehensible, except one which was subsequently revised. Construct validity of the G-SWAL-QOL was demonstrated by moderate to high correlations with the ADI-D (Spearman's rho 0.36 - 0.88). The G-SWAL-QOL was able to differentiate between patients with dysphagia and healthy controls (p < 0.001) and was sensitive to disease severity measured by different food textures. Reliability of the G-SWAL-QOL was good to excellent for both internal consistency (Cronbach's α > 0.7 for all domains, except eating desire [α = 0.69]) and test-retest reliability (Spearman's rho ≥ 0.68 for all domains; ICC > 0.8 for all domains). The G-SWAL-QOL is a valid and reliable measuring tool for dysphagia-specific quality of life in German-speaking persons.

Cultural adaptation and validation of the Norwegian version of the swallowing quality of life questionnaire (SWAL-QOL)

“…The symptom frequency battery and all subscales, with the exception of eating duration and eating desire reached the recommended Cronbach’s α cut off of ≥0.80 for group level research. Lower estimates for these two subscales were similar to other culturally adapted versions of the SWAL-QOL [22, 23, 28]. A possible explanation for this may be the original sentence formulation used for these subscales including double negatives and discrepancies with translation.…”

Validation of the Arabic version of swallowing quality of life questionnaire

“…SWAL-QOL is a self-report questionnaire used to evaluate the impact of swallowing problems on QOL [9]. Its original version was translated to different languages and has been used as a gold standard tool in various dysphagia researches tackling QOL aspects [13][14][15][16][17][18][19].…”

“…The SWAL-QOL has been translated to many languages such as Dutch [13], French [14], Chinese [15], Swedish [16], Persian [17], German [18], and Arabic [19] (its linguistic validation was tested only but its validation and reliability has not been determined).…”

Swallowing-related quality of life among oral-feeding Chinese patients with Parkinson’s disease – a preliminary study using Chinese SWAL-QOL

“…The SWAL-QOL can serve as an important tool in monitoring the patient's perspective on the efficacy of treatment. Currently, the SWAL-QOL questionnaire has been validated in an English-speaking [12][13][14] and German-speaking population [15], while the Chinese version of the Swallowing Quality-of-Life Questionnaire (C-SWAL-QOL) has also been validated for the Chinesespeaking population in Hong Kong [16]. The C-SWAL-QOL questionnaire has been reported to be a clinically valid and reliable tool for assessing swallowing-related quality of life in the Hong Kong Chinese population.…”