Development of a Binaural Masking Level Differences Test Application Using Tonal and Speech Stimuli in Persian and Assessing its Test-Retest Reliability in Normal-Hearing Young People

Background and Aim: The masking level difference (MLD) test is a behavioral test that assesses binaural interactions and central auditory processing. This study aims to design a binaural MLD (BMLD) test application using tonal and Speech Stimuli in Persian. Methods: In the first stage, the BMLD test application was designed in MATLAB software. Then, the spondaic words were recorded and added to the sound processing panel of the application. In the next stage, the MLD of tonal and speech stimuli was measured on 20 subjects aged 18–25 years. To examine the test-retest reliability of the application, all steps were repeated after one week. Results: The MLD values for tonal and speech stimuli under the SoNo-SπNo condition were significantly different from those under the SoNo-SoNπ condition (p<0.05). These values for tonal and speech stimuli were 10.50 and 6.12 dB under the SoNo- SπNo condition, and 6.85 and 4.43 under the SoNo- SoNπ condition. There was no significant difference in the MLD values between males and females. The intraclass correlation coefficient value for different phase conditions was more than 0.8, indicating the high reliability of the BMLD test application for tonal and speech stimuli in Persian (p<0.05). Conclusion: The designed BMLD test application using tonal and speech stimuli in Persian has similar results compared to the conventional methods of MLD test for other languages, therefore, this application can be used in audiology clinics in Iran to perform the MLD test. Keywords: Release from masking; masking; binaural hearing; software