Objectives
Knowledge about cochlear duct length (CDL) may assist electrode choice in cochlear implantation (CI). However, no gold standard for clinical applicable estimation of CDL exists. The aim of ...this study is (1) to determine the most reliable radiological imaging method and imaging processing software for measuring CDL from clinical routine imaging and (2) to accurately predict the insertion depth of the CI electrode.
Methods
Twenty human temporal bones were examined using different sectional imaging techniques (high-resolution computed tomography HRCT and cone beam computed tomography CBCT). CDL was measured using three methods: length estimation using (1) a dedicated preclinical 3D reconstruction software, (2) the established A-value method, and (3) a clinically approved otosurgical planning software. Temporal bones were implanted with a 31.5-mm CI electrode and measurements were compared to a reference based on the CI electrode insertion angle measured by radiographs in Stenvers projection (CDL
reference
).
Results
A mean cochlear coverage of 74% (SD 7.4%) was found. The CDL
reference
showed significant differences to each other method (
p
< 0.001). The strongest correlation to the CDL
reference
was found for the otosurgical planning software-based method obtained from HRCT (CDL
SW-HRCT
;
r
= 0.87,
p
< 0.001) and from CBCT (CDL
SW-CBCT
;
r
= 0.76,
p
< 0.001). Overall, CDL was underestimated by each applied method. The inter-rater reliability was fair for the CDL estimation based on 3D reconstruction from CBCT (CDL
3D-CBCT
; intra-class correlation coefficient ICC = 0.43), good for CDL estimation based on 3D reconstruction from HRCT (CDL
3D-HRCT
; ICC = 0.71), poor for CDL estimation based on the A-value method from HRCT (CDL
A-HRCT
; ICC = 0.29), and excellent for CDL estimation based on the A-value method from CBCT (CDL
A-CBCT
; ICC = 0.87) as well as for the CDL
SW-HRCT
(ICC = 0.94), CDL
SW-CBCT
(ICC = 0.94) and CDL
reference
(ICC = 0.87).
Conclusions
All approaches would have led to an electrode choice of rather too short electrodes. Concerning treatment decisions based on CDL measurements, the otosurgical planning software-based method has to be recommended. The best inter-rater reliability was found for CDL
A-CBCT
, for CDL
SW-HRCT
, for CDL
SW-CBCT
, and for CDL
reference
.
Key Points
•
Clinically applicable calculations using high-resolution CT and cone beam CT underestimate the cochlear size
.
•
Ten percent of cochlear duct length need to be added to current calculations in order to predict the postoperative CI electrode position
.
•
The clinically approved otosurgical planning software-based method software is the most suitable to estimate the cochlear duct length and shows an excellent inter-rater reliability
.
To analyze intensity-latency functions of intraoperative auditory evoked brainstem responses (ABRs) to stimulation by the Vibrant Soundbridge (VSB) active middle ear implant with respect to coupling ...efficiency, VSB evoked ABR thresholds, and coupling modality oval window (OW) placement vs. Incus placement and vs. round window (RW) placement.
Exploratory study.
Bi-centric study at tertiary referral centers.
Twenty-four patients (10 female, 14 male, mean age: 58 years) who received a VSB.
Wave-V intensity-latency functions of intraoperative VSB evoked ABRs using a modified audio processor programmed to preoperative bone conduction thresholds for stimulation. Threshold level correction to coupling efficiency and ABR thresholds. Individual plots and exponential function fits.
After ABR threshold level correction, the latency functions could be aligned. A large variance of latencies was observed at individual threshold level. Wave-V latency was longest in the Incus placement subgroup (9.73 ms, SD: 1.04) as compared to OW placement subgroup (9.47 ms, SD: 1.05), with the shortest latency in the RW placement subgroup (8.99 ms, SD: 0.68). For increasing stimulation levels, the variance decreased with intensity-latency function slopes converging toward a steady-state (saturation) latency caused by saturation of audio processor (stimulation) gain. Latency saturation was reached at a stimulation level of 50 dB nHL for the OW placement subgroup, 35 dB nHL for the Incus placement subgroup, and 30 dB nHL for the RW placement subgroup. The latency and saturation results indicated decreased dynamic range for RW placement, i.e., reverse stimulation.
VSB evoked ABR wave-V intensity-latency function slopes were similar to acoustic stimulation at high stimulation levels with a shift toward longer latencies caused by audio processor signal delay. Saturation of latencies occurred for higher stimulation levels due to saturation of audio processor gain. Thus, the analysis of VSB evoked intensity-latency functions appears to allow for the objective assessment of a patient's individual dynamic range. This can further improve diagnostics as well as intraoperative and postoperative quality control.
Zusammenfassung
Hintergrund:
Sprachaudiometrische Messungen unter Störschalleinflüssen sind grundlegender Bestandteil bei der Evaluation des Versorgungsergebnisses apparativer Hörversorgungen. Für ...die adaptive sprachaudiometrische Messung im Störschall bei Cochlea-Implantat(CI)-Trägern:innen existieren bisher noch keine Empfehlungen zur Wahl der Pegelsteuerungsmethode, d. h. entweder die adaptive Pegeländerung des Sprachsignals (S) bei konstantem Störgeräusch (N) oder die adaptive Pegeländerung von N bei konstantem S.
Fragestellung:
Hat die verwendete Pegelsteuerung beim Oldenburger Satztest (OLSA) einen Einfluss auf die Ergebnisse der monaural gemessenen Sprachverständlichkeitsschwelle (SVS) im Störschall?
Material und Methoden:
Insgesamt wurden von 50 CI-Trägern:innen die im Rahmen der klinischen Routine erzeugten OLSA-Messreihen im Störgeräusch mit unterschiedlicher Pegelsteuerung sowie sprachaudiometrischen Messungen in Ruhe mittels Freiburger Sprachtest ausgewertet und verglichen.
Ergebnisse:
In Abhängigkeit von der Pegelsteuerung im OLSA zeigen sich keine signifikanten Unterschiede zwischen den ermittelten Sprachverständlichkeitsschwellen, die kleiner als 5
dB
S/N
sind. Unter 55 % Einsilberverständlichkeit im FBE wird die SVS im OLSA größer als 5
dB
S/N
.
Schlussfolgerungen:
Damit bei den Messungen mit positivem S/N der Summenpegel möglichst konstant gehalten wird bzw. nur wenig ansteigt, empfiehlt sich aus klinisch audiologischer und methodischer Sicht die Durchführung der adaptiven monauralen Sprachverständlichkeitsmessung mit konstantem Sprachsignal bei 65
dB
SPL
. Zudem ist die Prüfung der monauralen Sprachverständlichkeit im Störschall erst ab einer Einsilberverständlichkeit von mindestens 55 % (65
dB
SPL
) sinnvoll.
Objective : The current study investigates whether, during a Cochlear Implant (CI) surgery, conditioning (i.e. applying short bursts of electrical stimulation) within a saline solution can have ...positive effects on subsequent intra-operative measurements. We hypothesize that, based on previous research, the impedance values will be reduced, and that the reproducibility of Electrically Evoked Compound Action Potentials (ECAPs) is improved as a result of conditioning. Methods : We conditioned half of the electrode contacts, within a saline solution, before CI insertion, using 23 MEDEL implants. Impedance was measured for both the conditioned and non-conditioned groups at five time points. Repeated ECAP recordings were measured and compared between the conditioned and non-conditioned groups. Results : Impedance of the electrode contacts were reduced by 31% after conditioning in saline solution; however, there were no clinically relevant differences after the implantation of the electrode array. The hypothesis that measurement reproducibility would be increased after conditioning could not be confirmed with our data. Within the saline solution, we observed that 44% of the electrode contacts were covered with air bubbles, which most disappeared after implantation. However, these air bubbles limited the effectiveness of the conditioning within the saline solution. Lastly, the effect of conditioning on the reference electrode stimulation was approximately 16% of the total reduction in impedance. Conclusion : Our data does not suggest that intraoperative conditioning is clinically required for cochlear implantation with MED-EL implants. Additionally, an in-vivo ECAP recording can be considered as a method of conditioning the electrode contacts. Significance : We confirm that the common clinical practice does not need to be changed.
Objective measurements may assist in indicating cochlear implants and in predicting outcomes of cochlear implantation surgery. Using electrically evoked compound action potentials (ECAP), information ...about the function of the auditory nerve can be obtained by analyzing responses to electrical stimulation transmitted and derived by the recording electrode. The aim of this study was to determine whether ECAP characteristics differ depending on the stimulated intracochlear region and the size of the cochlea.
Retrospective cohort study.
University Medical center, tertiary academic referral center.
Patients undergoing cochlear implant surgery between 2015 and 2018.
Cochlear implantation with FLEXsoft electrode arrays (length 31.5 mm, 12 stimulating channels).
The cochlear duct length (CDL) and the cochlear coverage (CC) were measured using a new computed tomography-based software and correlated to the postoperative speech performance. Additionally, ECAP were measured and associated to the CDL.
A total of 59 ears of 53 cochlear implant users with a mean age of 63.6 (SD 14.9) years were included. The mean estimated CDL was 35.0 (SD 2.2) mm. The mean CC was 90.3% (SD 5.5%). A total of 4,873 ECAP were measured. A statistically significant, moderate, negative correlation between the ECAP slope and the site of stimulation was found (r = -0.29, 95% confidence interval: -0.32 to -0.27, p < 0.0001). No correlation between the CC and the speech performance was found (r = -0.08, 95% confidence interval: -0.33 to 0.18 p = 0.52).
ECAP slopes seem to be a reliable tool to identify the electrode's position inside the cochlea and also showed correlations to the anatomy of the patient. A combination of objective measurements such as anatomical parameters and ECAPs are helpful to assist the postoperative fitting and are promising tools to improve patient care.
Accurate positioning of the electrode array during cochlear implant (CI) surgery is crucial for achieving optimal hearing outcomes. Traditionally, postoperative radiological imaging has been used to ...assess electrode position. Transimpedance matrix (TIM) measurements have also emerged as a promising method for assessing electrode position. This involves utilizing electric field imaging to create an electric distance matrix by analyzing voltage variations among adjacent electrodes. This study aimed to investigate the feasibility of using intraoperative TIM measurements to estimate electrode position and monitor postoperative changes.
Retrospective cohort study.
University Medical center, tertiary academic referral center.
Patients undergoing CI (CI622) surgery between January 2019 and June 2022.
CI electrode positions and maximal angular insertion depths (maxAID) were determined using X-ray imaging according to Stenvers' projection. The mean gradient phase (MGP) was extracted from the TIM, and a correlation between the MGP and maxAID was examined. A model was then built to estimate the maxAID using the MGP, and changes in electrode location over time were assessed using this model.
Twenty-four patients were included in this study. A positive correlation between the maxAID and the MGP ( R = 0.7, p = 0.0001) was found. The established model was able to predict the maxAID with an accuracy of 27.7 ± 4.4°. Comparing intraoperative and postoperative TIM measurements, a decrease of 24.1° ± 10.7° in maxAID over time was observed.
TIM measurements are useful for estimating the insertion depth of the electrode and monitoring changes in the electrode's position over time.
Purpose: Using naturalistic synthesized speech, we determined the relative importance of acoustic cues in voice gender and age perception in cochlear implant (CI) users. Method: We investigated 28 CI ...users' abilities to utilize fundamental frequency (F0) and timbre in perceiving voice gender (Experiment 1) and vocal age (Experiment 2). Parameter-specific voice morphing was used to selectively control acoustic cues (F0; time; timbre, i.e., formant frequencies, spectral-level information, and aperiodicity, as defined in TANDEM-STRAIGHT) in voice stimuli. Individual differences in CI users' performance were quantified via deviations from the mean performance of 19 normal-hearing (NH) listeners. Results: CI users' gender perception seemed exclusively based on F0, whereas NH listeners efficiently used timbre. For age perception, timbre was more informative than F0 for both groups, with minor contributions of temporal cues. While a few CI users performed comparable to NH listeners overall, others were at chance. Separate analyses confirmed that even high-performing CI users classified gender almost exclusively based on F0. While high performers could discriminate age in male and female voices, low performers were close to chance overall but used F0 as a misleading cue to age (classifying female voices as young and male voices as old). Satisfaction with CI generally correlated with performance in age perception. Conclusions: We confirmed that CI users' gender classification is mainly based on F0. However, high performers could make reasonable usage of timbre cues in age perception. Overall, parameter-specific morphing can serve to objectively assess individual profiles of CI users' abilities to perceive nonverbal social-communicative vocal signals.
Speech audiometry measurements under the influence of background noise are a fundamental part of evaluating the outcome of hearing care. As yet far, there are no recommendations for selecting a ...suitable method for adaptive speech audiometry measurements in background noise in cochlear implant (CI) care, so either the choice the adaptive level change of the speech signal (S) with constant noise (N) or the adaptive level change of N with constant S.
Do the measurement results of the monaural speechrecognition threshold in noise (SRT) with the Oldenburg Sentence Test (OLSA) depend on the choice of level control?
A total of 50 series of measurements with OLSA in noise and the Freiburg speech intelligibility test in quiet (FBE) on middle-aged CI patients from clinical routine.
There is no significant difference in the measurement results with different level controls when the SRT is less than 5 Formula: see text. Below 55 % monosyllabic intelligibility in quiet, the SRT in noise becomes greater than 5 Formula: see text.
From a clinical, audiological and methodological point of view, it is advisable to carry out the adaptive monaural speech intelligibility measurement with a constant speech signal at 65 Formula: see text.
Background
Attendance teaching is the predominant teaching method at universities but needs to be questioned in the context of digital transformation. This study establishes and evaluates a method to ...accomplish electronic learning to supplement traditional attendance courses.
Materials and methods
Surgery was transmitted in real-time conditions via an online live stream from the surgical theater. Visualization was transferred from a fully digital surgical microscope, an endoscope or an environmental camera in high definition quality. Students were able to participate at home from their personal computer. After following the surgery, they participated in an online-evaluation.
Results
A total of 65 students participated in the live stream. The majority of students (61.54%) indicated a significant subjective increase in knowledge after participation. The majority of students (53.85%) indicated that live surgeries should be offered as a permanent component in addition to classroom teaching. Likewise, a broader offer was desired by many students (63.08%).
Conclusions
Live streaming of surgery is a promising approach as an alternative or supplement to traditional attendance teaching. An expansion of digital teaching can be explicitly supported on the basis of this study.
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