No adaptation in the amplitude modulation domain in trained listeners.

The present study shows that on average, exposure to a 15 min, 5 kHz tone modulated sinusoidally in amplitude at 16 Hz with a 100% depth does not affect significantly amplitude modulation (AM) detection thresholds measured between 4 and 64 Hz when listeners are extensively trained to the AM detection task, with and without adaptor before data collection. These results are compatible with previous work given that a clear 6-dB adaptation effect was observed during the first pilot trials. However, the results reveal that adaptation effects are not robust, and suggest that the mechanisms underlying adaptation to AM must be reevaluated.