Publication:

Effect of aging and signal frequencies on masking level differences

Background The typical masking level differences (MLD) paradigm involves homophasic and antiphasic masking conditions. Objectives of the study were to develop homophasic and antiphasic stimulus, to find out the effect of signal frequency and age on MLD when all the antiphasic conditions are compared to the homophasic S0N0 and SπNπ condition and to find out effect of interaural time delay of stimulus on aging.

Methods 90 participants were divided into 3 groups of young adults, early presbycusic adults and geriatric presbycusic adults. Various stimuli were developed and presented. The MLD were obtained using homophasic and antiphasic stimuli at 4 frequencies 250, 500, 1000 and 2000 Hz. Subsequently, these were statistically analyzed using ANOVA and paired t-test.

Results All the conditions used in the study had some condition with and without significant differences. However, at 500 Hz in S0N0 homophasic condition all four antiphasic conditions among groups MLD and Interaural time delay between groups showed significant differences were present.

Conclusions From these findings, the best frequency is 500 Hz as the homophasic S0N0 baseline condition. A significant difference between the groups indicated presence of age-related effect on MLD and interaural time delay, suggesting that age related changes can be observed in the binaural hearing and temporal processing of the signals and can be measured using MLD.