Developmental Changes in Comodulation Masking Release for Puretones: A Cross-Sectional Study

Abstract

Comodulation Masking Release (CMR) is the phenomenon where there is enhancement in the signal detection when the fluctuations in the masker are correlated across different frequency bands. The development of CMR was studied in the present study across the age range 5 to 25 years at octave frequencies from 500 Hz to 4000 Hz. The participants were divided into 4 sub-groups according to their age. Two measures of CMR were measured based on the interaction of across channel and within channel cues underlying CMR. CMR1 was the difference between the signal detection in flanking band and comodulated masker condition. CMR2 was the difference between the signal detection in modulated on frequency band and comodulated masker condition. The results revealed a significant difference across age group in CMR1 at 500 Hz and in CMR2 at 1000 Hz. The significant difference was also noted between CMR1 and CMR2 in the age groups 10-15 years, 15- 20 years and 20-25 years. There was also significant difference noted in amount of CMR2 across frequencies in 10-15 years, 15-20 years and 20-25 years, whereas only in 20-25 years group CMR1 was significantly different across frequencies. From the results, it can be concluded that when only across channel cues are responsible for CMR, it develops by 20 years of age. But when both within channel cue and across channel cues are available, even 10 years and older perform equally.