Amplitude-modulation forward masking for listeners with and without hearing loss.

Amplitude-modulation (AM) forward masking was measured for listeners with normal hearing and sensorineural hearing loss at 4000 and 1000 Hz, using continuous and noncontinuous masker and signal carriers, respectively. A low-fluctuation noise (LFN) carrier was used for the "continuous carrier" conditions. An unmodulated low-fluctuation noise (U-LFN), an unmodulated Gaussian noise (U-GN), and an amplitude-modulation low-fluctuation noise (AM-LFN) were maskers for the "noncontinuous carrier" conditions. As predicted, U-GN yielded more masking than U-LFN and similar masking to AM-LFN, suggesting that U-GN resulted in AM forward masking. Contrary to predictions, no differences in masked thresholds were observed between listener groups.