Intraoperative Real-time Cochlear Response Telemetry Predicts Hearing Preservation in Cochlear Implantation

Abstract

RT-CRT can be used to predict early postoperative hearing loss and to potentially refine surgical technique. In the future, feedback of RT-CRT may prove to be a valuable tool for maximizing preservation of residual hearing or providing feedback on electrode contact with the basilar membrane.

Patterns Seen During Electrode Insertion Using Intracochlear Electrocochleography Obtained Directly Through a Cochlear Implant

“…As detailed elsewhere (9,10), one advantage of this method of intracochlear ECochG and related methods (5) is that there is not a need for additional instrumentation or pause of surgical progress beyond coupling of the external transmitting coil to the receiver/stimulator.…”

“…Intracochlear ECochG offers the potential for near real-time, continuous feedback reflective of cochlear micro-mechanics during CI electrode insertion (5,8–10,19–21). Intraoperative ECochG from the round window (2–4) and from within the cochlea itself is desirable with the long-term goal identifying and minimizing cochlear trauma and ensuring proper electrode placement during CI electrode insertion.…”

“…ECochG was first introduced 75 years ago as a near-field method for capturing acoustically evoked cochlear and auditory nerve responses (1). Interest in ECochG as a means of assessing cochlear micromechanics before, during, and after CI electrode placement from the vantage point of the round window (2–4) and from within the cochlea itself (5–10) has inspired a number of studies in recent years.…”

“…Existing work utilizing intracochlear ECochG has demonstrated its general feasibility and ease of application during CI electrode insertion (5,9,10), its relationship to preoperative hearing levels (19), and its potential to predict postoperative hearing levels and electrode position (20). The purpose of the present study was to characterize the ECochG patterns that the audiologist-surgeon team observes in the “insertion track”—the “live feed” received directly from the CI electrode during its advancement into the cochlea.…”

Electrophysiological Evidence of the Basilar-Membrane Travelling Wave and Frequency Place Coding of Sound in Cochlear Implant Recipients

“…The hardware was derived from the Cochlear Response Telemetry system previously described in detail by the investigators else-182 where [Campbell et al, 2016]; it utilizes the recording capabilities of a CI to measure acoustically evoked electrical signals directly from CI electrodes. The pressure stimulus was generated digitally by a USB data acquisition card (DT9847, Data Translation, MA, USA) and presented closed-field to the ear via an ER3A insert phone (Etymotics, IL, USA).…”