Validation of the Danish version of the McGill Ingestive Skills Assessment using classical test theory and the Rasch model.

Purpose: The study aimed to validate the Danish version of the Canadian the "McGill Ingestive Skills Assessment" (MISA-DK) for measuring dysphagia in frail elders.

Method: One-hundred and ten consecutive older medical patients were recruited to the study. Reliability was assessed by internal consistency (Chronbach's alpha). External construct validity (convergent and known-groups validity) was evaluated against theoretical constructs assessing the complex concept of ingestive skills. Internal construct validity was tested using Rasch analysis.

Results: High internal consistency reliability with Chronbach's alpha of 0.77-0.95 was evident. External construct validity was supported by expected high correlations with most of the constructs related to ingestive skills (r(s) = 0.53 to r(s) = 0.66). The MISA-DK discriminated significantly between known-groups. Fit to the Rasch model (x(2) (df) = 12 (12), p = 0.424) and unidimensionality of the MISA-DK was confirmed after resolving disordered thresholds for 11 items and adjustment of local dependency.

Conclusion: The psychometric properties of the MISA-DK equal the original Canadian version. Assessment of internal construct validity indicated multidimensionality due to local dependency. Although achieving good fit to the Rasch model after adjustments, additional studies are needed to establish cross-cultural validity. Finally, establishment of the inter- and intra-rater reliability of the MISA-DK is also needed.