Amplitude modulation detection and modulation masking in school-age children and adults

Abstract

Two experiments were performed to better understand on- and off-frequency modulation masking in normal-hearing school-age children and adults. Experiment 1 estimated thresholds for detecting 16-, 64- or 256-Hz sinusoidal amplitude modulation (AM) imposed on a 4300-Hz pure tone. Thresholds tended to improve with age, with larger developmental effects for 64- and 256-Hz AM than 16-Hz AM. Detection of 16-Hz AM was also measured with a 1000-Hz off-frequency masker tone carrying 16-Hz AM. Off-frequency modulation masking was larger for younger than older children and adults when the masker was gated with the target, but not when the masker was continuous. Experiment 2 measured detection of 16- or 64-Hz sinusoidal AM carried on a bandpass noise with and without additional on-frequency masker AM. Children and adults demonstrated modulation masking with similar tuning to modulation rate. Rate-dependent age effects for AM detection on a pure-tone carrier are consistent with maturation of temporal resolution, an effect that may be obscured by modulation masking for noise carriers. Children were more susceptible than adults to off-frequency modulation masking for gated stimuli, consistent with maturation in the ability to listen selectively in frequency, but the children were not more susceptible to on-frequency modulation masking than adults.

Reduced processing efficiency impacts auditory detection of amplitude modulation in children: Evidence from an experimental and modelling study

“…Evolution of AM detection and AM masking from 6 to 9 years of age and in children versus adults AM detection was tested with carriers with or without inherent random (competing) AM fluctuations (i.e., narrowband noises in the Noise condition, versus pure tones in the Tone condition). As expected based on previous studies (Hall and Grose, 1994;Banai et al, 2011;Peter et al, 2014;Buss et al, 2019;Cabrera et al, 2019), AMDTs were not overall adult-like by 9 years of age. We also observed that the thresholds did not significantly improve with age between 6 and 9 years.…”

“…In this connection, previous studies have shown differences in AM masking effects between young children versus adults. Specifically, Buss et al (2019) have observed higher susceptibility to AM masking in 5-year-olds than in adults for off-frequency conditions but not for on-frequency conditions, interpreted as the sign of ongoing maturation of selective listening. Cabrera et al (2019), in turn, found increasing susceptibility to AM masking between 5 and 7 years of age when comparing AM detection thresholds for deterministic vs non-deterministic carriers (pure tones vs narrowband noises respectively).…”

“…As to the first hypothesis, previous investigations have overall shown early maturity in both infants and children of the sensory-processing mechanisms involved in AM processing, when measuring AM detection thresholds at rates from 4 to 128 Hz using broadband or narrowband noise carriers (Cabrera et al, 2019;Hall and Grose 1994;Walker et al, 2019). To the best of our knowledge, only one study reported temporal acuity to be worse in children than adults (Buss et al, 2019): in this study, AM detection thresholds were measured at different rates (16,64 and 256 Hz) and larger difference in AM detection thresholds between adults and children (5-to-11-year-olds) was found at the higher rates tested. To further assess the sensory maturity of AM processing, AM maskers have been employed.…”

“…However, this study also indicated that infants show poorer AM sensitivity, i.e., higher AM detection thresholds, than adult listeners. Coherently, studies conducted with older children have shown that auditory sensitivity to AM continues to develop up to 11 years of age (Banai et al, 2011;Buss et al, 2019;Cabrera et al, 2019;Hall and Grose, 1994;Peter et al, 2014). Two hypotheses have been put forward to explain such a late development of AM sensitivity.…”