Gap detection in school-age children and adults: effects of inherent envelope modulation and the availability of cues across frequency.

PURPOSE

The present study evaluated the effects of inherent envelope modulation and the availability of cues across frequency on behavioral gap detection with noise-band stimuli in school-age children.

METHOD

Listeners were 34 normal-hearing children (ages 5.2-15.6 years) and 12 normal-hearing adults (ages 18.5-28.8 years). Stimuli were continuous bands of noise centered on 2000 Hz, either 1000- or 25-Hz wide. In addition to Gaussian noise at these bandwidths, there were conditions using 25-Hz-wide noise bands modified to either accentuate or minimize inherent envelope modulation (staccato and low-fluctuation noise, respectively).

RESULTS

Within the 25-Hz-wide conditions, adults' gap detection thresholds were highest in the staccato, lower in the Gaussian, and lowest in the low-fluctuation noise. Similar trends were evident in children's thresholds, although inherent envelope modulation had a smaller effect on children than on adults. Whereas adults' thresholds were comparable for the 1000-Hz-wide Gaussian and 25-Hz-wide low-fluctuation stimulus, children's performance converged on adults' performance at a younger age for the 1000-Hz-wide Gaussian stimulus.

CONCLUSIONS

Results are consistent with the idea that children are less susceptible to the disruptive effects of inherent envelope modulation than adults when detecting a gap in a narrow-band noise. Further, the ability to use spectrally distributed gap detection cues appears to mature relatively early in childhood.