Clinical masking: applicability of plateau and optimized methods in hearing thresholds testing.

Background: Many situations may raise difficulties when obtaining hearing thresholds for each ear separately. These situations demand the use of masking. The plateau method has been used for more than four decades. Nevertheless, in 2004 a different masking protocol was suggested, called the optimized method, to replace the plateau method in specific cases.

Aim: To evaluate the feasibility of two clinical masking methods, plateau and optimized, in the testing of hearing thresholds.

Method: Participants of this study were 40 individuals aged 15 to 65 years, with either unilateral or bilateral hearing losses. All participants underwent air and bone conduction pure tone audiometry for both ears, with and without the use of the two masking methods, considering unilateral, bilateral, symmetrical and bone-only patterns.

Results: There was no statistically significant difference between the two masking methods for obtaining the air conduction hearing thresholds considering the tested situations. However, there was a higher percentage difference for the symmetrical pattern in the air conduction retest situation. There was a statistically significant difference between the plateau and optimized methods regarding the bone conduction thresholds for the symmetrical and bone-only patterns.

Conclusion: The plateau method can be used for all patterns and the optimized method is the most effective for unilateral and bilateral patterns. Therefore, it is important for the audiologist to have the knowledge about the application of both masking methods in order to obtain more reliable results.