A notched-noise precursor affects both diotic and dichotic notched-noise masking

The present study investigates how diotic and dichotic masked thresholds, in a notched-noise masking paradigm, are affected by activation of the Medial OlivoCochlear (MOC) reflex. Thresholds were obtained for a 500-Hz pure tone diotic or a dichotic signal, S (S0 or Sπ respectively), in the presence of a simultaneous or forward diotic masker (bandpass noise with no notch or a 400-Hz notch). A diotic precursor sound (bandpass noise with a 400- or 800-Hz notch) was presented prior to the signal and masker to activate the MOC reflex. For simultaneous- and forward-masking conditions, the decrease in masked thresholds as a notch was introduced in the masker was larger for the diotic than for the dichotic condition. This resulted in a reduced binaural masking level difference (BMLD) for the masker with a notch. The precursor augmented these two effects. The results indicate that the effect of the precursor, eliciting the MOC reflex, is less pronounced when binaural cues are processed

Bilateral and Unilateral Cochlear Implant Users Compared on Speech Perception in Noise

Objective: Compare speech performance in noise with matched bilateral cochlear implant (ClCl) and unilateral cochlear implant (Cl only) users. Design: Thirty CICI and 30 CI-only subjects were tested on a battery of speech perception tests in noise that use an eight-loudspeaker array. Results: On average, ClCl subject's performance with speech in noise was significantly better than the Cl-only subjects. Conclusion: The CICI group showed significantly better performance on speech perception in noise compared with the CI-only subjects, supporting the hypothesis that CICI is more beneficial than CI only