Voltage matrix algorithm for intraoperative detection of cochlear implant electrode misplacement.

Objective To develop an algorithm, based on the voltage matrix, for detecting regular cochlear implant (CI) electrode position during the implantation procedure, tip fold-over or basal kinking for lateral-wall electrodes. The availability of an algorithm would be valuable in clinical routine, as incorrect positioning of the electrode array can potentially be recognized intraoperatively. Design In this retrospective study intraoperative voltage matrix and postoperative digital volume tomography of 525 CI recipients were analyzed.

Electrically Evoked Stapedius Reflex Measurements in Cochlear Implantation and its Application in the Postoperative Fitting Process.

Measuring the electrically evoked stapedius reflex during the fitting of cochlear implants (CIs) provides a reliable estimation of maximum comfort levels, resulting in the programming of the CI with high hearing comfort and good speech understanding. Detection of the stapedius reflex and the required stimulation level on each implant channel is already being performed during surgery, whereby intraoperative stapedius reflexes are observed through the surgical microscope. Intraoperative stapedius reflex detection is both an indicator that the auditory nerve is responding to electrical stimulation up to the brainstem and a test for the ability to perform postoperative stapedius reflex measurements.

Word Recognition with a Cochlear Implant in Relation to Prediction and Electrode Position.

Background: the word recognition score (WRS) achieved with cochlear implants (CIs) varies widely. To account for this, a predictive model was developed based on patients' age and their pre-operative WRS. This retrospective study aimed to find out whether the insertion depth of the nucleus lateral-wall electrode arrays contributes to the deviation of the CI-achieved WRS from the predicted WRS.

Stapedius reflex thresholds obtained in a free sound field as an indicator for over- and understimulation in cochlear implant listeners.

Objective: The goal of this study was to determine open field stapedius reflex thresholds (oSRTs) in CI patients with fittings based on subjective loudness ratings. A further objective was to compare these oSRTs and those of eSRT-based fittings that are similar to the oSRTs of normal hearing.

Design: Impedance measurements of the ear drum were taken while subjects were wearing their audio processors.

Stapedius reflex evoked in free sound field in cochlear implant users compared to normal-hearing listeners.

Objective: To determine the relation between stapedius reflex thresholds in cochlear implant users evoked once through direct electric stimulation on single channels (ESRT) and once through acoustic stimulation in free sound field. For comparison, stapedius reflex thresholds were obtained in free sound field in a normal-hearing control group.

Design: For each participant a new ESRT-based fitting was created.

Estimation of insertion depth angle based on cochlea diameter and linear insertion depth: a prediction tool for the CI422.

Beside the cochlear size, the linear insertion depth (LID) influences the insertion depth angle of cochlear implant electrode arrays. For the specific implant CI422 the recommended LID is not fixed but can vary continuously between 20 and 25 mm. In the current study, the influence of cochlea size and LID on the final insertion depth angle was investigated to develop a prediction tool for the insertion depth angle by means of cochlea diameter and LID.

Insertion depth angles of cochlear implant arrays with varying length: a temporal bone study.

Hypothesis: The aim of the study is to investigate the insertion depth angles for different types of electrode arrays and its variability depending on the individual cochlear size.

Background: Preoperative estimation of the insertion depth angles for different electrode arrays can help surgeons choose the optimal electrode length, especially for low-frequency residual hearing preservation.

Methods: Four different electrode arrays varying in lengths (20, 24, 28, and 31 mm) were inserted in 10 temporal bones to quantify the insertion depth angle of each inserted electrode.