The acoustically evoked potentials in the case of stimulation by frequency modulation (FM) near the hearing threshold, compared with tone burst stimulation.

The present investigation concerned the possibility of obtaining higher AEP amplitudes at or near the hearing threshold by stimulation with frequency-modulated sinusoidal tones (FM stimulation) than by tone burst stimulation. With FM stimulation the frequency changes may lead to changes in the coupler sound pressure level in the headphone (additional amplitude or intensity modulation) as well as changes in sensation levels due to frequency-dependent hearing sensitivity which have to be compensated for. To ensure comparability of FM and tone burst stimulation it has also to be considered that the FM frequency increment does not substantially exceed the critical bandwidth of the human ear. With these conditions taken into account, no combination of FM stimulation parameters was found that resulted in a larger AEP amplitude than tone burst stimulation. With comparable stimulation parameters, the AEP amplitudes were identical for FM and tone burst stimulation.