Intraoperative ECAP thresholds in cochlear implant patients with 512,522 and 532 electrodes
23 April 2019 (online)
Measurement of NRTs (Neural Response telemetry) and impedances is considered as standard for cochlear implantation. Studies so far performed, don't differentiate whether measurement has taken place in open or closed operative Setting, although as well impedances as also NRT values are influenced by this fact.
In 65 patients with 512,522 or 532 electrodes intraoperative measurement of impedances and NRTs was performed in an open setting and 10 minutes later in a closed setting. Postoperative control was done 6 and 12 months after surgery.
Intraoperative measurement in open setting resulted in significantly higher impedances compared to closed setting 10 min later. 522 electrodes also showed significantly higher NRT values in an open setting, whereas 512 and 532 didn't show significant differences. NRT values in 532 and 512 diminuished significantly after 6 and 12 months while the 522 electrodes showed no significant changes.
Taking into account that intraoperative NRT and impedance measurements have an important impact on the results in the first implant fitting, intraoperative measurements should always be performed in a closed operative setting.