ObjectivesQuestionnaires are essential for measuring tinnitus severity and intervention-related change but there is no standard instrument used routinely in research settings. Most tinnitus questionnaires are optimised for measuring severity but not change. However, the Tinnitus Functional Index (TFI) claims to be optimised for both. It has not however been fully validated for research purposes. Here we evaluate the relevant psychometric properties of the TFI, specifically the questionnaire factor structure, reproducibility, validity and responsiveness guided by quality criteria for the measurement properties of health-related questionnaires.MethodsThe study involved a retrospective analysis of data collected for 294 members of the general public who participated in a randomised controlled trial of a novel tinnitus device (ClinicalTrials.gov Identifier: NCT01541969). Participants completed up to eight commonly used assessment questionnaires including the TFI, Tinnitus Handicap Inventory (THI), Tinnitus Handicap Questionnaire (THQ), a Visual Analogue Scale of loudness (VAS-Loudness), Percentage Annoyance question, the Beck's Depression Inventory (BDI), Beck's Anxiety Inventory (BAI), and the World Health Organisation Quality of Life-Bref (WHOQOL-BREF). A series of analyses assessed the study objectives. Forty four participants completed the TFI at a second visit (within 7–21 days and before receiving any intervention) providing data for reproducibility assessments.ResultsThe 8-factor structure was not fully confirmed for this general (non-clinical) population. Whilst it was acceptable standalone subscale, the ‘auditory’ factor showed poor loading with the higher order factor ‘functional impact of tinnitus’. Reproducibility assessments for the overall TFI indicate high internal consistency (α = 0.80) and extremely high reliability (ICC: 0.91), whilst agreement was borderline acceptable (93%). Construct validity was demonstrated by high correlations between scores on the TFI and THI (r = 0.82) and THQ (r = 0.82), moderate correlations with VAS-L (r = 0.46), PR-A (r = 0.58), BDI (r = 0.57), BAI (r = 0.39) and WHOQOL (r = −0.48). Floor effects were observed for more than 50% of the items. A smallest detectable change score of 22.4 is proposed for the TFI global score.ConclusionEven though the proposed 8-factor structure was not fully confirmed for this population, the TFI appears to cover multiple symptom domains, and to measure the construct of tinnitus with an excellent reliability in distinguishing between patients. While the TFI may discriminate those whose tinnitus is not a problem, floor effects in many items means it is less appropriate as a measure of change in this subgroup. Further investigation is needed to determine whether these effects are relevant in other populations.

BackgroundA Core Outcome Set (COS) is an agreed list of outcomes that are measured and reported in all clinical trials for a particular health condition. An ‘e-Delphi’ is an increasingly popular method for developing a COS whereby stakeholders are consulted via a multi-round online survey to reach agreement regarding the most important outcomes. Many COS studies seek diverse, international input that includes professionals and healthcare users. However, the recruitment and retention of participants can be deterred by various factors (e.g. language barriers and iterative, time-consuming rounds). This report evaluates the effectiveness of recruitment and retention methods used in the Core Outcome Measures in Tinnitus International Delphi (COMiT’ID) study using participant feedback from healthcare users, healthcare practitioners, researchers, commercial representatives and funders.MethodsA range of methods were applied to recruit participants to the study and maintain engagement over the three rounds. Feedback on recruitment and retention methods was collected using a twenty-item online questionnaire, with free text comments.ResultsA personalised email invitation was the most frequent recruitment route, and 719 professionals and healthcare users consented to take part. Retention of each stakeholder group ranged from 76 to 91% completing all three e-Delphi rounds. Feedback was given by 379 respondents. A majority of respondents were satisfied with the study methods that were implemented to promote retention. Over 55% indicated that their overall experience closely matched their expectations at the start of the study, and over 90% felt that their contribution was appreciated.ConclusionsThis report highlights study methods that worked well with respect to recruitment and retention, and those that did not. Findings provide a unique contribution to the growing evidence base of good practice in COS development by demonstrating the relative effectiveness of recruitment and retention methods for an e-Delphi survey.Trial registrationThis project was registered (November 2014) in the database of the Core Outcome Measures in Effectiveness Trials (COMET) initiative. The protocol is published in Trials (doi:10.1186/s13063-017-2123-0).

Hypersensitivity to external sounds is often comorbid with tinnitus and may be significant for adherence to certain types of tinnitus management. Therefore, a clear measure of sensitivity to sound is important. The aim of this study was to evaluate the validity and reliability of the Hyperacusis Questionnaire (HQ) for use as a measurement tool using data from a sample of 264 adults who took part in tinnitus research. We evaluated the HQ factor structure, internal consistency, convergent and discriminant validity, and floor and ceiling effects. Internal consistency was high (Cronbach's alpha = 0.88) and moderate correlations were observed between the HQ, uncomfortable loudness levels, and other health questionnaires. Confirmatory factor analysis revealed that the original HQ three-factor solution and a one-factor solution were both a poor fit to the data. Four problematic items were removed and exploratory factor analysis identified a two-factor (attentional and social) solution. The original three-factor structure of the HQ was not confirmed. All fourteen items do not accurately assess hypersensitivity to sound in a tinnitus population. We propose a 10-item (2-factor) version of the HQ, which will need to be confirmed using a new tinnitus and perhaps nontinnitus population.