A cross-sectional validation study of the Swedish version of SWAL-QOL

The purpose of this study was to evaluate the psychometric properties of the Swedish version of the Swallowing Quality of Life questionnaire (SWAL-QOL). The study design was cross-sectional and the study was performed in patients with subjective oropharyngeal dysphagia due to head and neck (H&N) cancer (n = 85) or neurological disease (n = 30) and in a sample of age- and gender-matched controls (mean age = 63 years, 57% males) without subjective dysphagia (n = 115). The Short-Form 36 (SF-36) and Hospital Anxiety and Depression Scale (HADS) questionnaires were used for assessment of convergent and discriminant validity. The Swedish version of SWAL-QOL was well accepted, the response rate was high (>90%), and the number of missing items were very low (<1%). Overall, the questionnaire showed good to excellent psychometric properties, including floor and ceiling effects (range = 0-16 and 0-21%), internal consistency [Cronbach's α > 0.70 for all domains except Eating Duration (0.69) and Sleep (0.68)], test-retest reliability (intraclass correlations = 0.75-0.98) and convergent and discriminant validity as assessed by correlations between SWAL-QOL and SF-36 and HADS. SWAL-QOL also proved able to differentiate between dysphagic and nondysphagic patients (P < 0.00001) (known-groups validity) and sensitive to disease severity as measured by different food textures.