Modulation masking and masked speech perception in normal-hearing school-age children and adults

Abstract

It has recently been suggested that adults’ ability to recognize speech in noise is limited by the inherent modulation of that noise—a form of modulation masking. This study evaluated whether immature masked speech perception in school-age children could be due to greater susceptibility to modulation masking. To gauge modulation sensitivity, the first experiment measured sinusoidal modulation detection for rates of 10–300 Hz carried by a 5000-Hz pure tone. There were large individual differences, but little evidence of a child/adult difference. This adult-like modulation detection for a tonal carrier contrasts with published findings of adult/child differences in modulation detection for a noise-band carrier, suggesting that children may be more susceptible to modulation masking than adults. The second experiment evaluated masked sentence recognition for speech that was filtered into 28 adjacent equivalent rectangular bands (100–7800 Hz), with alternate bands presented to opposite ears. Maskers were composed of either noise bands or tones, one centered on each speech band. These stimuli have been argued to characterize effects of modulation masking. Young children tended to perform more poorly than adults overall. Masker effects will be discussed in terms of possible developmental differences in energetic and modulation masking.