Extra-high-frequency noise remotely masks and alters temporal integration at lower frequencies

A quasi-free-field technique was used to assess the effects of extra-high-frequency-band masking on detection threshold of middle and high (1-7 kHz) frequencies. At an SPL of 60 dB, the 10- to 20-kHz masker produced a slight amount of masking. Increasing the masking level by another 5 dB produced a disproportionate increase of the detection thresholds. This increase was greatest in response to 4- and 5-kHz stimuli, and was detected with both constant and pulsed tones. Decreasing the bandwidth of the masker reduced the magnitude of the effect, but not the frequency-specific pattern of the remote masking. Extra-high-frequency masking also increased the amount of temporal integration at middle and high frequencies. The data are discussed in reference to peripheral and central neural changes associated with sensorineural hearing loss.