Modulation interference in cochlear implants

Modulation interference, in which the temporal envelope of a signal is rendered less salient due to the presence of a competing temporal envelope of a masker, has been modeled as the result of modulation-tuned filters operating in the midbrain. In listeners with cochlear implants (CIs) who rely more heavily on the speech temporal envelope, such interference may be particularly problematic for speech perception in competing, fluctuating backgrounds. Here, we present evidence for modulation interference in CI users from our laboratory, using both non-speech and speech targets. Maskers were presented either in the same ear or in the contralateral ear relative to the target, and either concurrently with the target or preceding the target (forward masking). Tasks include the detection of the temporal envelope on the target as well as the discrimination of temporal envelopes between targets. Results suggest that modulation interference plays an important role in CI users, reducing the salience of the speech tem...