Swallowing-related quality of life in oral cavity cancer - The German version of the Anderson Dysphagia Inventory

The objective of this study was to validate the German version of the Anderson Dysphagia Inventory (ADI), as well as to grade it by using health-related quality of life as an external criterion. A total of 102 patients (26 women, 76 men) aged 34-90 years (61.1 +/- 10.8) with a treated squamous cell carcinoma of the oral cavity participated in the study. All study participants independently completed the German version of the ADI and the SF-36 questionnaire on health-related quality of life. The German ADI was tested for its validity and reliability, and subjected to a factor analysis. The internal consistency reliability of the ADI was calculated using Cronbach's alpha coefficient and was equal to 0.942. In the split-half reliability the Spearman-Brown coefficient scored 0.916. Factor analysis showed a one-factor result. The correlation coefficients between the point scores of the German ADI and the following clinical parameters demonstrated construct validity: radiation (p < 0.001), T-classification (p=0.002), surgical method (p=0.018), not, however, tumor site (p=0.115). The grading system was as follows: scores < 55 are regarded as "definitely noticeable"; scores 55-70 are considered as "more noticeable than not"; while scores > 70 are classified as " more unnoticeable than not". The German translation of the ADI is a validated and reliable method to assess swallowing-related quality of life.