Effect of Cochlear Implantation on the Endocochlear Potential and Stria Vascularis

McClellan, Joseph H.; He, Wenxuan; Raja, Joseline; Stark, Gemaine; Ren, Tianying; Reiss, Lina A. J.

doi:10.1097/mao.0000000000002949

Cited by 7 publications

(7 citation statements)

References 25 publications

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“…On the other hand, removal may cause additional mechanical trauma and/or loss of perilymph. It has been shown that the endocochlear potential might be affected by presence of the electrode array ( Oshima et al, 2014 ; McClellan et al, 2021 ). However, those studies also suggest that the role of the endocochlear potential is delayed after cochlear implantation, and might affect predominantly the area with direct trauma.…”

Section: Discussionmentioning

confidence: 99%

Acute effects of cochleostomy and electrode-array insertion on compound action potentials in normal-hearing guinea pigs

Jwair

Ramekers²,

Thomeer³

et al. 2023

Front. Neurosci.

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IntroductionElectrocochleography (ECochG) is increasingly used in cochlear implant (CI) surgery, in order to monitor the effect of insertion of the electrode array aiming to preserve residual hearing. However, obtained results are often difficult to interpret. Here we aim to relate changes in ECochG responses to acute trauma induced by different stages of cochlear implantation by performing ECochG at multiple time points during the procedure in normal-hearing guinea pigs.Materials and methodsEleven normal-hearing guinea pigs received a gold-ball electrode that was fixed in the round-window niche. ECochG recordings were performed during the four steps of cochlear implantation using the gold-ball electrode: (1) Bullostomy to expose the round window, (2) hand-drilling of 0.5–0.6 mm cochleostomy in the basal turn near the round window, (3) insertion of a short flexible electrode array, and (4) withdrawal of electrode array. Acoustical stimuli were tones varying in frequency (0.25–16 kHz) and sound level. The ECochG signal was primarily analyzed in terms of threshold, amplitude, and latency of the compound action potential (CAP). Midmodiolar sections of the implanted cochleas were analyzed in terms of trauma to hair cells, modiolar wall, osseous spiral lamina (OSL) and lateral wall.ResultsAnimals were assigned to cochlear trauma categories: minimal (n = 3), moderate (n = 5), or severe (n = 3). After cochleostomy and array insertion, CAP threshold shifts increased with trauma severity. At each stage a threshold shift at high frequencies (4–16 kHz) was accompanied with a threshold shift at low frequencies (0.25–2 kHz) that was 10–20 dB smaller. Withdrawal of the array led to a further worsening of responses, which probably indicates that insertion and removal trauma affected the responses rather than the mere presence of the array. In two instances, CAP threshold shifts were considerably larger than threshold shifts of cochlear microphonics, which could be explained by neural damage due to OSL fracture. A change in amplitudes at high sound levels was strongly correlated with threshold shifts, which is relevant for clinical ECochG performed at one sound level.ConclusionBasal trauma caused by cochleostomy and/or array insertion should be minimized in order to preserve the low-frequency residual hearing of CI recipients.

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Section: Discussionmentioning

confidence: 99%

Acute effects of cochleostomy and electrode-array insertion on compound action potentials in normal-hearing guinea pigs

Jwair

Ramekers²,

Thomeer³

et al. 2023

Front. Neurosci.

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“…Many otologic disorders such as noise-induced hearing loss, endolymphatic hydrops and presbycusis have been identified to be related to alterations in CBF ( Nakashima et al, 2003 ). Additionally, impairment of CBF is likely to also play a pivotal role in loss of residual hearing after CI ( McClellan et al, 2021 ).…”

Section: Discussionmentioning

confidence: 99%

Cochlear implantation impairs intracochlear microcirculation and counteracts iNOS induction in guinea pigs

Ernst¹,

Heinrich

Fries³

et al. 2023

Front. Cell. Neurosci.

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IntroductionPreservation of residual hearing remains a great challenge during cochlear implantation. Cochlear implant (CI) electrode array insertion induces changes in the microvasculature as well as nitric oxide (NO)-dependent vessel dysfunction which have been identified as possible mediators of residual hearing loss after cochlear implantation.MethodsA total of 24 guinea pigs were randomized to receive either a CI (n = 12) or a sham procedure (sham) by performing a cochleostomy without electrode array insertion (n = 12). The hearing threshold was determined using frequency-specific compound action potentials. To gain visual access to the stria vascularis, a microscopic window was created in the osseous cochlear lateral wall. Cochlear blood flow (CBF) and cochlear microvascular permeability (CMP) were evaluated immediately after treatment, as well as after 1 and 2 h, respectively. Finally, cochleae were resected for subsequent immunohistochemical analysis of the iNOS expression.ResultsThe sham control group showed no change in mean CBF after 1 h (104.2 ± 0.7%) and 2 h (100.8 ± 3.6%) compared to baseline. In contrast, cochlear implantation resulted in a significant continuous decrease in CBF after 1 h (78.8 ± 8.1%, p < 0.001) and 2 h (60.6 ± 11.3%, p < 0.001). Additionally, the CI group exhibited a significantly increased CMP (+44.9% compared to baseline, p < 0.0001) and a significant increase in median hearing threshold (20.4 vs. 2.5 dB SPL, p = 0.0009) compared to sham after 2 h. Intriguingly, the CI group showed significantly lower iNOS-expression levels in the organ of Corti (329.5 vs. 54.33 AU, p = 0.0003), stria vascularis (596.7 vs. 48.51 AU, p < 0.0001), interdental cells (564.0 vs. 109.1 AU, p = 0.0003) and limbus fibrocytes (119.4 vs. 18.69 AU, p = 0.0286).ConclusionMechanical and NO-dependent microvascular dysfunction seem to play a pivotal role in residual hearing loss after CI electrode array insertion. This may be facilitated by the implantation associated decrease in iNOS expression. Therefore, stabilization of cochlear microcirculation could be a therapeutic strategy to preserve residual hearing.

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“…In mammals, the transfer of potassium ions through ion channels, influenced by ion concentrations, generates the highest positive DC electrochemical potential ranging from 70 to 100 mV. [ 339 , 340 ] Two miniature glass electrodes were inserted into the cochlea of an anesthetized Hartley Albino guinea pig, with the electrode leads connected to an internal ultra‐low‐power wireless signal electronic chip on the external side of the guinea pig. A net positive power of 60−2840 pW was provided to load the circuit and run the chip for 5 h. Each cell of living organisms can actively or passively transport Na + and K + via pumps and channels to eventually generate transmembrane potentials, thus showing the unique advantages of flexibility and universality, allowing the extraction of bioenergy directly from the diverse implantation site, as shown in Figure 7 A .…”

Section: Internal Power Harvesters (Iphs) As Atbsmentioning

confidence: 99%

Biomimetic Exogenous “Tissue Batteries” as Artificial Power Sources for Implantable Bioelectronic Devices Manufacturing

Yue,

Wang,

Xie

et al. 2024

Advanced Science

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Implantable bioelectronic devices (IBDs) have gained attention for their capacity to conformably detect physiological and pathological signals and further provide internal therapy. However, traditional power sources integrated into these IBDs possess intricate limitations such as bulkiness, rigidity, and biotoxicity. Recently, artificial “tissue batteries” (ATBs) have diffusely developed as artificial power sources for IBDs manufacturing, enabling comprehensive biological‐activity monitoring, diagnosis, and therapy. ATBs are on‐demand and designed to accommodate the soft and confining curved placement space of organisms, minimizing interface discrepancies, and providing ample power for clinical applications. This review presents the near‐term advancements in ATBs, with a focus on their miniaturization, flexibility, biodegradability, and power density. Furthermore, it delves into material‐screening, structural‐design, and energy density across three distinct categories of TBs, distinguished by power supply strategies. These types encompass innovative energy storage devices (chemical batteries and supercapacitors), power conversion devices that harness power from human‐body (biofuel cells, thermoelectric nanogenerators, bio‐potential devices, piezoelectric harvesters, and triboelectric devices), and energy transfer devices that receive and utilize external energy (radiofrequency‐ultrasound energy harvesters, ultrasound‐induced energy harvesters, and photovoltaic devices). Ultimately, future challenges and prospects emphasize ATBs with the indispensability of bio‐safety, flexibility, and high‐volume energy density as crucial components in long‐term implantable bioelectronic devices.

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Effect of Cochlear Implantation on the Endocochlear Potential and Stria Vascularis

Cited by 7 publications

References 25 publications

Acute effects of cochleostomy and electrode-array insertion on compound action potentials in normal-hearing guinea pigs

Acute effects of cochleostomy and electrode-array insertion on compound action potentials in normal-hearing guinea pigs

Cochlear implantation impairs intracochlear microcirculation and counteracts iNOS induction in guinea pigs

Biomimetic Exogenous “Tissue Batteries” as Artificial Power Sources for Implantable Bioelectronic Devices Manufacturing

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