scholarly journals Effect of cochlear implant electrode insertion on middle-ear function as measured by intra-operative laser Doppler vibrometry

2009 ◽  
Vol 123 (7) ◽  
pp. 723-729 ◽  
Author(s):  
N Donnelly ◽  
A Bibas ◽  
D Jiang ◽  
D-E Bamiou ◽  
C Santulli ◽  
...  
Keyword(s):  
Cochlear Implant ◽  
Middle Ear ◽  
Low Frequency ◽  
Laser Doppler ◽  
Frequency Function ◽  
Laser Doppler Vibrometry ◽  
Variable Effect ◽  
Custom Made ◽  
Electrode Insertion ◽  
The Impact

AbstractHypothesis:The aim of this study was to investigate the impact of cochlear implant electrode insertion on middle-ear low frequency function in humans.Background:Preservation of residual low frequency hearing with addition of electrical speech processing can improve the speech perception abilities and hearing in noise of cochlear implant users. Preservation of low frequency hearing requires an intact middle-ear conductive mechanism in addition to intact inner-ear mechanisms. Little is known about the effect of a cochlear implant electrode on middle-ear function.Methods:Stapes displacement was measured in seven patients undergoing cochlear implantation. Measurements were carried out intra-operatively before and after electrode insertion. Each patient acted as his or her own control. Sound was delivered into the external auditory canal via a speaker and calibrated via a probe microphone. The speaker and probe microphone were integrated into an individually custom-made ear mould. Ossicular displacement in response to a multisine stimulus at 80 dB SPL was measured at the incudostapedial joint via the posterior tympanotomy, using an operating microscope mounted laser Doppler vibrometry system.Results:Insertion of a cochlear implant electrode into the scala tympani had a variable effect on stapes displacement. In three patients, there was little change in stapes displacement following electrode insertion. In two patients, there was a significant increase, while in a further two there was a significant reduction in stapes displacement. This variability may reflect alteration of cochlear impedance, possibly due to differing loss of perilymph associated with the electrode insertion.Conclusion:Insertion of a cochlear implant electrode produces a change in stapes displacement at low frequencies, which may have an effect on residual low frequency hearing thresholds.

scholarly journals Effect of Underwater Insertion on Intracochlear Pressure

2020 ◽  
Vol 7 ◽  
Author(s):  
Conrad Riemann ◽  
Holger Sudhoff ◽  
Ingo Todt
Keyword(s):  
Hyaluronic Acid ◽  
Cochlear Implant ◽  
Middle Ear ◽  
Round Window ◽  
Maximum Amplitude ◽  
Influential Factor ◽  
Fluid State ◽  
Insertion Techniques ◽  
Electrode Insertion ◽  
Intracochlear Pressure

Background: The importance of intracochlear pressure during cochlear electrode insertion for the preservation of residual hearing has been widely discussed. Various aspects of pre-insertional, intra-insertional, and post-insertional relevant conditions affect intracochlear pressure. The fluid situation at the round window during electrode insertion has been shown to be an influential factor.Aims/Objectives: The aim of the study was to compare various insertion techniques in terms of the fluid situation at the round window.Material and Methods: We performed insertion of cochlear implant electrodes in a curled artificial cochlear model. We placed and fixed the pressure sensor at the tip of the cochlea. In parallel to the insertions, we evaluated the maximum amplitude of intracochlear pressure under four different fluid conditions at the round window: (1) hyaluronic acid; (2) moisturized electrode, dry middle ear; (3) middle ear filled with fluid (underwater); and (4) moisturized electrode, wet middle ear, indirectly inserted.Results: We observed that the insertional intracochlear pressure is dependent on the fluid situation in front of the round window. The lowest amplitude changes were observed for the moisturized electrode indirectly inserted in a wet middle ear (0.13 mmHg ± 0.07), and the highest values were observed for insertion through hyaluronic acid in front of the round window (0.64 mmHg ± 0.31).Conclusions: The fluid state in front of the round window influences the intracochlear pressure value during cochlear implant electrode insertion in our model. Indirect insertion of a moisturized electrode through a wet middle ear experimentally generated the lowest pressure values. Hyaluronic acid in front of the round window leads to high intracochlear pressure in our non-validated artificial model.

scholarly journals Extra- and Intracochlear Electrocochleography in Cochlear Implant Recipients

2015 ◽  
Vol 20 (5) ◽  
pp. 339-348 ◽  
Author(s):  
Adrian Dalbert ◽  
Flurin Pfiffner ◽  
Christof Röösli ◽  
Konrad Thoele ◽  
Jae Hoon Sim ◽  
...  
Keyword(s):  
Cochlear Implant ◽  
Middle Ear ◽  
Cochlear Implantation ◽  
Low Frequency ◽  
Electrode Array ◽  
Postoperative Phase ◽  
Residual Hearing ◽  
Middle Ear Effusion ◽  
Cochlear Function ◽  
Ear Effusion

Objective: To monitor cochlear function by extra- and intracochlear electrocochleography (ECoG) during and after cochlear implantation and thereby to enhance the understanding of changes in cochlear function following cochlear implantation surgery. Methods: ECoG responses to acoustic stimuli of 250, 500 and 1,000 Hz were recorded in 9 cochlear implant recipients with presurgical residual hearing. During surgery extracochlear ECoG recordings were performed before and after insertion of the cochlear implant electrode array. After insertion of the electrode array, intracochlear ECoG recordings were conducted using intracochlear electrode contacts as recording electrodes. Intracochlear ECoG recordings were performed up to 6 months after implantation. ECoG findings were correlated with findings from audiometric tests. Results: Extra- and intracochlear ECoG responses could be recorded in all subjects. Extracochlear ECoG recordings during surgery showed moderate changes. Loss or reduction of the ECoG signal at all three frequencies did not occur during cochlear implantation. During the first week following surgery, conductive hearing loss, due to middle ear effusion, led to a decrease in intracochlear ECoG signal amplitudes. This was not attributable to changes of cochlear function. All persistent reductions in ECoG response magnitude after normalization of the tympanogram occurred during the first week following implantation. Thresholds of ECoG signals were at or below hearing thresholds in all cases. Conclusion: Gross intracochlear trauma during surgery appears to be rare. In the early postoperative phase the ability to assess cochlear status by ECoG recordings was limited due to the regular occurrence of middle ear effusion. Still, intracochlear ECoG along with tympanogram recordings suggests that any changes of low-frequency cochlear function occur mainly during the first week after cochlear implantation. ECoG seems to be a promising tool to objectively assess changes in cochlear function in cochlear implant recipients and may allow further insight into the mechanisms underlying the loss of residual hearing.

Middle Ear Transmission Disorders—Tympanic Membrane Vibration Analysis by Laser-Doppler-Vibrometry

1994 ◽  
Vol 114 (1) ◽  
pp. 59-63 ◽  
Author(s):  
Norbert Stasche ◽  
Hans-Jochen Foth ◽  
Karl Hörmann ◽  
Antonio Baker ◽  
Christian Huthoff
Keyword(s):  
Tympanic Membrane ◽  
Middle Ear ◽  
Vibration Analysis ◽  
Laser Doppler ◽  
Laser Doppler Vibrometry ◽  
Membrane Vibration

scholarly journals Simulations and Measurements of Human Middle Ear Vibrations Using Multi-Body Systems and Laser-Doppler Vibrometry with the Floating Mass Transducer

Materials ◽  
2013 ◽  
Vol 6 (10) ◽  
pp. 4675-4688 ◽  
Author(s):  
Frank Böhnke ◽  
Theodor Bretan ◽  
Stefan Lehner ◽  
Tobias Strenger
Keyword(s):  
Middle Ear ◽  
Laser Doppler ◽  
Laser Doppler Vibrometry ◽  
Human Middle Ear ◽  
Multi Body

scholarly journals Laser Doppler vibrometry of the middle ear in humans: derivation dependence, variability, and bilateral differences

Medicina ◽  
2009 ◽  
Vol 45 (11) ◽  
pp. 878 ◽  
Author(s):  
Irina Arechvo ◽  
Nikoloz Lasurashvili ◽  
Matthias Bornitz ◽  
Zurab Kevanishvili ◽  
Thomas Zahnert
Keyword(s):  
Middle Ear ◽  
Membrane Surface ◽  
Reference Sample ◽  
Acoustic Stimulus ◽  
Stimulus Frequency ◽  
Laser Doppler ◽  
Intersubject Variability ◽  
Laser Doppler Vibrometry ◽  
Bilateral Differences ◽  
Middle Ear Transfer Function

Objective. Derivation dependence, inter- and intrasubject/intertest variability, bilateral differences of the eardrum vibration characteristics have been investigated using laser Doppler vibrometry (LDV). Material and methods. A total of 31 normally hearing adults were examined. In each subject, both ears were consecutively stimulated by the chirp acoustic stimulus that covered 500–3700-Hz frequencies. The laser beam was directed to and the reflection was consecutively picked up from the tympanic membrane surface. Results. LDV curves derived from different eardrum loci possessed dissimilar characteristics. The derivation area dependence was particularly apparent for the stimulus frequency constituents above 1500 Hz. The intersubject variability of LDV parameters exceeded the intrasubject/ intertest one. The intersubject divergences looked selectively distinct for the frequencies over 2000 Hz. Under repeated recordings, LDV parameters remained stable. The intertest differences, if appeared, concerned predominantly the magnitudes of separate frequency bands. LDV waveforms registered by experienced and beginner investigators were alike. Bilaterally derived LDV curves regularly differed from each other. In individual cases, the bilateral divergences approximated the intersubject deviation. Conclusions. The derivation area on the eardrum should be taken into account when estimating the actual LDV recording. Over repeated recordings in separate individuals, LDV waveforms are stable while the experience of investigator has slight if any influence on the principal LDV characteristics. Due to bilateral differences in the middle ear transfer function, in LDV testing of the ear suspected to the pathology, LDV recording from the opposite healthy ear could hardly be taken as an appropriate reference sample.

Laser Doppler vibrometry of the human middle ear: the technical point of view

1995 ◽  
Author(s):  
Hans-Jochen Foth ◽  
Matthias Brenner ◽  
Norbert Stasche ◽  
Karl Hoermann
Keyword(s):  
Middle Ear ◽  
Point Of View ◽  
Laser Doppler ◽  
Laser Doppler Vibrometry ◽  
Technical Point ◽  
Human Middle Ear

scholarly journals Frictional Behavior of Cochlear Electrode Array Is Dictated by Insertion Speed and Impacts Insertion Force

2021 ◽  
Vol 11 (11) ◽  
pp. 5162
Author(s):  
Dana Dohr ◽  
Nicklas Fiedler ◽  
Wolfram Schmidt ◽  
Niels Grabow ◽  
Robert Mlynski ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Cochlear Implant ◽  
Electrode Array ◽  
Mechanical Trauma ◽  
Electrode Arrays ◽  
Friction Behavior ◽  
Insertion Force ◽  
Friction Coefficients ◽  
Electrode Insertion ◽  
The Impact

Background: During cochlear implantation, the electrode array has significant friction with the sensitive endocochlear lining and causes mutual mechanical trauma while the array is being inserted. Both, the impact of insertion speed on electrode friction and the relationship of electrode insertion force and friction have not been adequately investigated to date. Methods: In this study, friction coefficients between a CI electrode array (31.5 mm) and a tissue simulating the endocochlear lining have been acquired, depending on different insertion speeds (0.1, 0.5, 1.0, 1.5, and 2.0 mm/s). Additionally, the electrode insertion forces during the placing into a scala tympani model were recorded and correlated with the friction coefficient. Results: It was shown that the friction coefficient reached the lowest value at an insertion speed of 0.1 mm/s (0.24 ± 0.13), a maximum occurred at 1.5 mm/s (0.59 ± 0.12), and dropped again at 2 mm/s (0.45 ± 0.11). Similar patterns were observed for the insertion forces. Consequently, a high correlation coefficient (0.9) was obtained between the insertion forces and friction coefficients. Conclusion: The present study reveals a non-linear increase in electrode array friction, when insertion speed raises and reports a high correlation between friction coefficient and electrode insertion force. This dependence is a relevant future parameter to evaluate and reduce cochlear implant insertion trauma. Significance statement: Here, we demonstrated a dependence between cochlear electrode insertion speed and its friction behavior and a high correlation to insertion force. Our study provides valuable information for the evaluation and prevention of cochlear implant insertion trauma and supports the optimization of cochlear electrode arrays regarding friction characteristics.

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