Cochlear implants enable experimental control of the olivocochlear reflex unavailable in normal hearing

Evidence

Cochlear implant users thus lack MOCR effects, but these effects can be reinstated, and thus the role(s) of the MOCR in hearing can be assessed by using dynamic rather than fixed compression functions. For example, contralateral MOCR effects could be reinstated by making compression in a given frequency channel vary dynamically depending upon an appropriate control signal from a contralateral processor (Fig. 1 ). … Using this approach, the CI offers the possibility to mimic (with dynamic compression) or not mimic (with fixed compression) the effects of the MOCR. Such activation or deactivation of MOCR effects is not possible for subjects who have normal hearing. — Dijk, Pim van, Physiology, Psychoacoustics and…, 1940

In the fitting of modern CIs, the amount and endpoints of the compression are adjusted for each frequency channel and its associated intra-cochlear electrode(s). The compression once set is fixed. Cochlear implant users thus lack MOCR effects, but these effects can be reinstated, and thus the role(s) of the MOCR in hearing can be assessed by using dynamic rather than fixed compression functions. — Dijk, Pim van, Physiology, Psychoacoustics and…, 1943

Categorization

• SEED: An essay on how a clinical device becomes an experimental probe — the CI as a tool for basic science that no natural-hearing subject permits.
• DEFINE: MOCR (medial olivocochlear reflex) effects are introduced functionally via what they do — modulating compression — before any formal definition section.
• corroborated: 2 independent passages support this claim — Dijk, Pim van, Physiology, Psychoacoustics and…, 1940; Dijk, Pim van, Physiology, Psychoacoustics and…, 1943