Cross-Cultural Adaptation and Validation of the Italian Version of the Dysphagia Handicap Index (I-DHI)

The Dysphagia Handicap Index (DHI) is a valid Health-related Quality of Life (HRQOL) questionnaire for patients with oropharyngeal dysphagia (OD) of heterogeneous etiologies. The study aimed at crossculturally translating and adapting the DHI into Italian (I-DHI) and analyzing I-DHI reliability, validity, and interpretability. The I-DHI was developed according to Beaton et al. 5-stage process and completed by 75 adult OD patients and 166 healthy adults. Twenty-six patients filled out the I-DHI twice, 2 weeks apart, for test-retest reliability purposes. Sixty-two patients completed the Italian-Swallowing Quality of Life Questionnaire (I-SWAL-QoL) for criterion validity analysis. Construct validity was tested comparing I-DHI scores among patients with different instrumentally assessed and self-rated OD severity, comparing patients and healthy participants and testing Spearman's correlations among I-DHI subscales. I-DHI interpretability was assessed and normative data were generated. Participants autonomously completed the I-DHI in maximum 10 min. Reliability proved satisfactory for all I-DHI subscales (internal consistency: alpha > .76; test-retest reliability: intraclass correlation coefficient > .96, k = .81). Mild to moderate correlations (- .26 <= rho <= - .72) were found between I-DHI and I-SWAL-QoL subscales. Construct validity proved satisfactory as (i) moderate to strong correlations (.51 <= rho <= .90) were found among I-DHI subscales; (ii) patients with more severe instrumentally or self-assessed OD reported higher I-DHI scores (p < .05); and (iii) OD patients scored higher at I-DHI compared to healthy participants (p < .05). Interpretability analyses revealed a floor effect for the Emotional subscale only and higher I-DHI scores (p < .05) for healthy participants > 65 years. In conclusion, the I-DHI is a reliable and valid HRQOL tool for Italian adults with OD.