MOCR speech-in-noise unmasking remains unproven because selective deactivation is impossible in humans

Evidence

A more widely accepted role is that the MOCR possibly facilitates understanding speech in noisy environments. This idea is based on the fact that MOC efferent activation restores the dynamic range of auditory nerve fibre responses in noisy backgrounds to values observed in quiet (Fig. 5 in Guinan 2006 ), something that probably improves the neural coding of speech embedded in noise (Brown et al. 2010 ; Chintanpalli et al. 2012 ; Clark et al. 2012 ). The evidence in support for this unmasking role of the MOCR during natural listening is, however, still indirect (Kim et al. 2006 ). A direct demonstration would require being able to selectively deactivate the MOCR while keeping afferent auditory nerve fibres functional. To our knowledge, such an experiment has not been possible for human subjects up until now. Here, we argue that the experiment can be done in an approximate manner using cochlear implants (CIs). — Dijk, Pim van, Physiology, Psychoacoustics and…, 1942

Categorization

• QUESTION: The claim that cochlear implants enable an approximate selective-deactivation experiment is worth pursuing — how does a CI bypass or preserve the efferent pathway?