Evidence that stimulus bandwidth affects temporal resolution and temporal integration in naive listeners

Abstract

The separation of auditory events in time (temporal resolution) and the summation of these events over time (temporal integration) are both essential to normal hearing. Here, it is reported that both of these abilities are affected by stimulus bandwidth in naive listeners. In a single group of 30 naive listeners, amplitude-modulation detection thresholds were determined over a range of modulation rates, and signal-detection thresholds over a range of signal durations, using noises of two different bandwidths (0.25 kHz and 3.80 kHz), both with a 4.40-kHz upper cutoff frequency. Amplitude-modulation thresholds were adjusted mathematically to compensate for reductions in modulation depth introduced by filtering after modulation. The average time constants estimated from these data were significantly larger for the narrowband than the broadband noise for both temporal resolution (5.1 versus 1.3 ms; p<0.0001) and temporal integration (251 versus 13 ms; p<0.0001). Thus, naive listeners showed shorter temporal resolution and integration windows with a wider stimulus bandwidth, suggesting that, at least for this population, both of these temporal-processing abilities are influenced by the spectral parameters of the input. [Work supported by a grant from NIH/NIDCD.]