Measuring the psychosocial consequences of hearing loss in a working adult population: focus on validity and reliability of the Italian translation of the hearing handicap inventory.

Despite increasing demand for questionnaires for assessing hearing handicap and the effectiveness of some tools across different languages, empirical studies to evaluate the reliability and the validity of translations of original English questionnaires into an Italian version have not been reported in the literature, thus making comparisons of Italian experimental and clinical data across cultures and countries impossible. This study tested the global assumption that the Hearing Handicap Inventory for Adults (HHIA), that is one of the most widely used instruments in English-speaking countries, can be adapted to the Italian language maintaining the reliability and clinical validity of the original version. The English version of this 25-item, self-assessment questionnaire was developed by Newman et al. in 1990 and special emphasis was placed on emotional reaction and social limitations perceived by hearing-impaired subjects and scored separately. This tool was translated into the Italian language by a forward and backward technique, as established by the IQOLA (International Quality of Life Assessment) project. Overall, 94 subjects, aged 18-65 years, with acquired hearing impairment and 104 individuals with no hearing problems, well-matched for socio-demographic variables, were enrolled in the study in a case-control design. Reliability of the Italian version of HHIA was tested by measuring internal consistency and test-retest reproducibility. Validity was assessed by using construct, convergent and discriminant methods. A Cronbach's alpha coefficient near 0.90 confirmed a more than acceptable internal consistency and a highly statistically significant Spearman's correlation coefficient (< 0.005) between scores of the two administrations at an interval of one month documented an excellent stability of the questionnaire over time. Construct validity was demonstrated by a correlation between the severity of hearing loss and the score of questionnaire (< 0.005) and convergent validity was supported by a significant correlation between the scores of the emotional and socio/situational subscales of the HHIA to the analogous subscales of a health-related quality of life questionnaire (MOS 36-Item Short Form Health Survey) (< 0.005). Finally, since hearing-impaired subjects scored significantly higher than controls on HHIA (< 0.005), it clearly emerged that also the Italian version of HHIA differentiates the two populations (those with and those without hearing problems) demonstrating a robust discriminant validity. Given the lack of appropriate measures to assess hearing handicap in Italy, the results achieved in this study, confirm that the HHIA, Italian version, is suitable for both experimental and clinical use.