Asymmetric Flankers in Comodulation Masking Release

Detection of auditory signals may be improved when maskers far from the frequency of the target signal are coherently amplitude-modulated. This improvement of signal detection is called comodulation masking release (CMR). In the CMR experiments, flankers have been usually arranged symmetrically. In practice, we will be confronted with a problem by using symmetric flankers due to the limited output of clinical audiometers, especially at high-frequency. We aimed to check whether flanker arrangement has any effect on the amount of CMR, especially when there is no flankers with a frequency higher than the signal. Subjects and. Eighteen normal hearing listeners ranging in age from 20 to 46 years old participated. Symmetric (2-2) and asymmetric (3-1 and 4-0) flankers were used and then the amount of CMR compared among them. Our results showed in the same numbers of flankers, there were no statistically CMR differences between symmetric and asymmetric arrangement. Also when we did not have a flanker at a frequency higher than the signal and all flankers were placed below the signal, there was no statistically difference with the symmetric arrangement. The asymmetry of the flankers and also omitting the flankers with a frequency higher than the signal, have no effect on CMR results. We concluded that CMR can be considered by using clinical audiometer.