Validity of the Italian adaptation of the Tinnitus Handicap Inventory; focus on quality of life and psychological distress in tinnitus-sufferers

The aim of this study was to determine the validity of the Italian translation of the Tinnitus Handicap Inventory (THI) by Newman et al. in order to make this self-report measure of perceived tinnitus handicap available both for clinical and research purposes in our country and to contribute to its cross-cultural validation as a self-report measure of perceived severity of tinnitus. The Italian translation of the Tinnitus Handicap Inventory (THI) was administered to 100 outpatients suffering from chronic tinnitus, aged between 20 and 82 years, who attended the audiological tertiary centres of the University Hospital of Modena and the Regional Hospital of Treviso. No segregation of cases was made on audiometric results; patients suffering from vertigo and neurological diseases were excluded. Pyschoacoustic characteristics of tinnitus (loudness and pitch) were determined and all patients also completed the MOS 36-Item Short Form Health Survey to assess self-perceived quality of life and the Hospital Anxiety and Depression Scale as a measure of self-perceived levels of anxiety and depression. The THI-I showed a robust internal consistency reliability (Cronbach's alpha = 0.91) that was only slightly lower than the original version (Tinnitus Handicap Inventory-US; Cronbach's alpha = 0.93) and its Danish (Cronbach's alpha = 0.93) and Portuguese (Cronbach's alpha = 0.94) translations. Also its two subscales (Functional and Emotional) showed a good internal consistency reliability (Cronbach's alpha = 0.85 and 0.86, respectively). On the other hand, the Catastrophic subscale showed an unacceptable internal consistency reliability as it is too short in length (5 items). A confirmatory factor analysis failed to demonstrate that the 3 subscales of the THI-I correspond to 3 different factors. Close correlations were found between the total score of the Italian translation of the Tinnitus Handicap Inventory and all the subscales of the MOS 36-Item Short Form Health Survey (SF-36) and the Hospital Anxiety and Depression Scale scores indicating a good construct validity. Moreover, these statistically significant correlations (p < 0.005) confirmed that the self-report tinnitus handicap is largely related to psychological distress and a deterioration in the quality of life. On the other hand, it was confirmed that the tinnitus perceived handicap is totally independent (p > 0.05) from its audiometrically-derived measures of loudness and pitch thus supporting previous studies that focused on the importance of non-auditory factors, namely somatic attention, psychological distress and coping strategies, in the generation of tinnitus annoyance. Finally the results of the present study suggest that the THI-I maintains its original validity and should be incorporated, together with other adequate psychometric questionnaires, in the audiological examination of patients suffering from tinnitus and that psychiatric counselling should be recommended for the suspected co-morbidity between tinnitus annoyance and psychological distress.