Objectives: To review our intraoperative and postoperative testing protocol
for cochlear implant patients. This study describes the methodologies and
applications of a new technique called neural response telemetry (NRT) for
the Nucleus CI24M cochlear implant system. NRT uses radiofrequency telemetr
y technology to measure the action potentials of the auditory nerve. Study
Design: We have developed a specific protocol for intraoperative testing of
the implant device before, during, and after implantation. This includes d
evice integrity tests, visual detection of electrical stapedius muscle refl
exes (VESR), and NRT, Methods: Our methodologies use the commercial softwar
e (Windows-based Diagnostic and Programming System [WIN-DPS] and NRT) for t
he Nucleus CI24M. We describe the details of our protocol used on all of th
e patients (14 adults and 14 children) who received CI24M implants at Mayo
Clinic (Rochester, MN), Our protocol correlates the NRT threshold with the
behavioral responses for each patient on at least four electrodes. Results:
From August 1, 1998, to December 31,1998, we completed electrode integrity
tests, NRT, and VESR testing intraoperatively on 12 patients with the Nucl
eus CI24M. We have measured normal implant function on all 28 of our CI24M
patients with one exception. One of our children had a device failure after
approximately 4 months as a result of head trauma We have also obtained NR
T results from an additional 10 patients postoperatively, Conclusions: The
measurement of device and electrode array function is quite simple with the
CI24M software. These measurements can be obtained intraoperatively as wel
l as postoperatively, We conclude that VESR and NRT measurements can be ver
y helpful in programming for patients with cochlear implants, especially ch
ildren, because they provides us with target settings for the speech proces
sor.