COMPARATIVE ANALYSIS OF DIFFERENT MASKING TECHNIQUES FOR PURE-TONE AUDIOMETRY BY USING MASKING DIAGRAMS

Abstract

INTRODUCTION AND OBJECTIVES. Searching pure-tone thresholds, contralateral masking in the non-test ear is needed when there are significant sensitivity differences between the left and right ear. There exist some graphic tools that enable reasoning and that provide greater certainty when introducing masking. We reviewed some used techniques for contralateral masking by using masking diagrams. The published references in our field afford different types of rules for clinical masking; however, they lack a theoretical basis. Software was developed based on the Lidén formulas, which quickly create masking diagrams. With these tools, we have compared three standard techniques in audiologic testing.

MATERIAL AND METHOD. The software was developed based on the Lidén formulas used for clinical masking, and we compared the Plateau method, the Turner method (also known as optimized) and a widespread technique in Argentina recommended by Diamante [1], call the ‘D’ method. Four different audiometric configurations were analyzed.

RESULTS. The Plateau method is the most suitable for any audiometric configuration. The Turner method, instead, shows limitations in cases of bilateral and symmetrical patterns. We have found in some cases, where masking needs to be applied, that the ‘D’ method does not indicate the necessity of doing so, thus assuming the unmasked (shadow) threshold to be the real one.

CONCLUSION. The Plateau method seems to be the only reliable approach for any audiometric configuration. Thus, attempts to shorten its development pose risks to its efficacy.