Background & aims: The aim of this study was to develop and evaluate the validity and reliability of a self-report inventory to measure symptomatic severity of oral-pharyngeal dysphagia.
Methods: Test-retest reliability and face, content, and construct validity of a prototype visual analogue scale inventory were assessed in 45 patients who had stable, neuromyogenic dysphagia.
Results: Normalized scores varied over time by -0.5% +/- 17.6% (95% confidence interval, -9.2% to 8.2%). Factor analysis identified a single factor (dysphagia), to which 18 of 19 questions contributed significantly, that accounted for 56% of total variance (P < 0.0001). After deletion of 2 questions with poor face validity and patient compliance, this proportion increased to 59%; mean test-retest change was -2% (95% confidence interval, -11% to 7%); and total score correlated highly with an independent global assessment severity score (r = 0.7; P < 0.0001). A mean 70% reduction in score (P < 0.0001) was observed after surgery in patients with Zenker's diverticulum (discriminant validity).
Conclusions: Applied to patients with neuromyogenic dysphagia, the 17-question inventory shows strong test-retest reliability over 2 weeks as well as face, content, and construct validity. Discriminant validity (responsiveness) has been demonstrated in a population with a correctable, structural cricopharyngeal disorder. Responsiveness of the instrument to treatment in neuromyogenic dysphagia remains to be quantified.