An Argument for Self-Report as a Reference Standard in Audiology.

Abstract

The primary components of a diagnostic accuracy study are an index test, the target condition (or disorder), and a reference standard. According to the Standards for Reporting Diagnostic Accuracy statement, the reference standard should be the best method available to independently determine if the results of an index test are correct. Pure-tone thresholds have been used as the "gold standard" for the validation of some tests used in audiology. Many studies, however, have shown a lack of agreement between the audiogram and the patient's perception of hearing ability. For example, patients with normal audiograms may report difficulty understanding speech in the presence of background noise. The primary purpose of this article is to present an argument for the use of self-report as a reference standard for diagnostic studies in the field of audiology. This will be in the form of a literature review on pure-tone threshold measures and self-report as reference standards. The secondary purpose is to determine the diagnostic accuracy of pure-tone threshold and Hearing-in-Noise Test (HINT) measures for the detection of a speech-recognition-in-noise disorder. Two groups of participants with normal pure-tone thresholds were evaluated. The King-Kopetzky syndrome (KKS) group was made up of participants with the self-report of speech-recognition-in-noise difficulties. The control group was made up of participants with no reports of speech-recognition-in-noise problems. The reference standard was self-report. Diagnostic accuracy of HINT and pure-tone threshold measures was determined by measuring group differences, sensitivity and specificity, and the area under the curve (AUC) for receiver-operating characteristic (ROC) curves. Forty-seven participants were tested. All participants were native speakers of American English. Twenty-two participants were in the control group and 25 in the KKS group. The groups were matched for age. Pure-tone threshold data were collected using the Hughson-Westlake procedure. Speech-recognition-in-noise data was collected using a software system and the standard HINT protocol. Statistical analyses were conducted using descriptive, correlational, two-sample t tests, and logistic regression. The literature review revealed that self-report has been used as a reference standard in investigations of patients with normal audiograms and the perception of difficulty understanding speech in the presence of background noise. Self-report may be a better indicator of hearing ability than pure-tone thresholds in some situations. The diagnostic accuracy investigation revealed statistically significant differences between control and KKS groups for HINT performance (p < 0.01), but not for pure-tone threshold measures. Better sensitivity was found for the HINT Composite score (88%) than pure-tone average (PTA; 28%). The specificities for the HINT Composite score and PTA were 77% and 95%, respectively. ROC curves revealed a greater AUC for the HINT Composite score (AUC = 0.87) than for PTA (AUC = 0.51). Self-report is a reasonable reference standard for studies on the diagnostic accuracy of speech-recognition-in-noise tests. For individuals with normal pure-tone thresholds, the HINT demonstrated a higher degree of diagnostic accuracy than pure-tone thresholds for the detection of speech-recognition-in-noise disorder.