Reply to: Psychometric properties of the Tinnitus Functional Index (TFI): Assessment in a UK research volunteer population

Integrating Distribution-Based and Anchor-Based Techniques to Identify Minimal Important Change for the Tinnitus Functional Index (TFI) Questionnaire

The Tinnitus Functional Index (TFI) was developed to be responsive to small treatment-related changes in the impact of tinnitus. Yet, no studies have integrated anchor-based and distribution-based techniques to produce a single Minimal Important Change (MIC) score. Here, we evaluated the responsiveness and interpretability of the TFI, determining for the first time a robust MIC score in a UK clinical population. Two-hundred and fifty-five patients with tinnitus participated in this prospective longitudinal validation study. Distribution-based estimates (Standard Error of Measurement, Smallest Detectable Change and Effect size) and anchor-based estimates of important change (minimal clinically important difference and Receiver Operator Curve optimal value) were calculated and then integrated using a visual anchor-based MIC distribution plot. A reduction in score of −14 was determined as the MIC estimate that exceeds the measurement error, most of the variability and reliably identifies patients demonstrating true improvement. It is therefore recommended that a reduction of 14 points should be used as a minimum change required when calculating statistical power and sample size in tinnitus intervention studies and assessing patients in clinical practice.

Development and Preliminary Evaluation of the Tinnitus Severity Short Form

Purpose Tinnitus, or the perception of sounds that occur without an external sound source, is a prevalent condition worldwide. For a subset of adults, tinnitus causes significant distress and impairment. Several patient-reported outcome measures have been developed to assess severity of tinnitus distress. However, at present, the field lacks a brief measure that is sensitive to treatment change. The purpose of the current study was to develop and preliminarily validate a brief questionnaire for tinnitus severity from two existing measures of tinnitus-related distress, the Tinnitus Handicap Inventory (THI) and Tinnitus Functional Index (TFI). Method Using data from nine study samples in the United States and United Kingdom, we conducted exploratory and confirmatory factor analyses to identify a short measure with good psychometric properties. We also assessed sensitivity to treatment-related change by examining associations with change in the TFI and THI. Finally, we conducted a confirmatory factor analysis of the final short questionnaire in a new sample of adults seeking treatment for tinnitus-related distress. Results We identified 10 items from the THI and TFI that exhibited limited loadings on secondary factors. The resulting Tinnitus Severity Short Form achieved good to excellent fit, including in a unique sample of individuals seeking online treatment for tinnitus, and appeared sensitive to treatment-related change. Conclusions The Tinnitus Severity Short Form developed in the current study may be a useful tool for the assessment of subjective severity and distress associated with tinnitus, especially when patient burden is a concern. Further research is necessary to fully validate the questionnaire for the assessment of treatment-related change.

Improving the assessment of functional impairment in tinnitus sufferers: validation of the German version of the Tinnitus Functional Index using a confirmatory factor analysis

OBJECTIVES

Chronic tinnitus negatively impacts daily functioning. To specifically assess this impairment, the Tinnitus Functional Index (TFI) was developed. The current study investigated the hierarchical, eight-factorial structure for the German TFI and examined its psychometric properties.

DESIGN

In an online assessment, the TFI and other validated health-related measurements were completed. Confirmatory factor analysis (CFA) was conducted to investigate the factorial structure by testing two competing models: (1) a general factor model, and (2) a hierarchical second-order factor model.

STUDY SAMPLE

316 research volunteers (59.8% female) with low to moderate tinnitus distress were included.

RESULTS

CFA revealed an insufficient fit of the data to the general factor model. For the hierarchical second-order factor model, an acceptable model fit was shown (χ²/df ratio = 2.74, RMSEA = 0.07, SRMR = 0.05, CFI = 0.95, TLI = 0.95). Correlational analyses between the TFI and measures assessing tinnitus distress, depression, sleeping difficulties, subjective well-being, and personality dimensions indicated high convergent and moderate discriminant validity. Internal consistency reliability was excellent.

CONCLUSIONS

The results confirm the hierarchical, eight-factorial structure of the German TFI. The TFI is a promising inventory that should be used on a regular basis.HighlightsThe results of our study confirm the hierarchical eight-factorial structure of the German TFI.Confirmatory factor analysis revealed an acceptable model fit of the data.Convergent validity of the German TFI was high.Discriminant validity of the German TFI was moderate.The German TFI is a reliable questionnaire to assess tinnitus functional impairment.

An auditory brainstem implant for treatment of unilateral tinnitus: protocol for an interventional pilot study

INTRODUCTION

Tinnitus may have a very severe impact on the quality of life. Unfortunately, for many patients, a satisfactory treatment modality is lacking. The auditory brainstem implant (ABI) was originally indicated for hearing restoration in patients with non-functional cochlear nerves, for example, in neurofibromatosis type II. In analogy to a cochlear implant (CI), it has been demonstrated that an ABI may reduce tinnitus as a beneficial side effect. For tinnitus treatment, an ABI may have an advantage over a CI, as cochlear implantation can harm inner ear structures due to its invasiveness, while an ABI is presumed to not damage anatomical structures. This is the first study to implant an ABI to investigate its effect on intractable tinnitus.

METHODS AND ANALYSIS

In this pilot study, 10 adults having incapacitating unilateral intractable tinnitus and ipsilateral severe hearing loss will have an ABI implanted. The ABI is switched on 6 weeks after implantation, followed by several fitting sessions aimed at finding an optimal stimulation strategy. The primary outcome will be the change in Tinnitus Functioning Index. Secondary outcomes will be tinnitus burden and quality of life (using Tinnitus Handicap Inventory and Hospital Anxiety and Depression Scale questionnaires), tinnitus characteristics (using Visual Analogue Scale, a tinnitus analysis), safety, audiometric and vestibular function. The end point is set at 1 year after implantation. Follow-up will continue until 5 years after implantation.

ETHICS AND DISSEMINATION

The protocol was reviewed and approved by the Institutional Review Board of the University Medical Centre Groningen, The Netherlands (METc 2015/479). The trial is registered at www.clinicialtrials.gov and will be updated if amendments are made. Results of this study will be disseminated in peer-reviewed journals and at scientific conferences.

TRIAL REGISTRATION NUMBER

NCT02630589.

TRIAL STATUS

Inclusion of first patient in November 2017. Data collection is in progress. Trial is open for further inclusion. The trial ends at 5 years after inclusion of the last patient.