Audiology and Neurotology

Cochlear Implantation with the CI512 and CI532 Precurved Electrode Arrays: One-Year Speech Recognition and Intraoperative Thresholds of Electrically Evoked Compound Action Potentials

17-12-2019 –

Introduction: Precurved cochlear implant (CI) electrode arrays were developed in an attempt to improve the auditory outcome of cochlear implantation, which varies greatly. The recent CI532 (Cochlear Corp., Sydney, Australia) may offer further advantages as its electrode array is thinner than previous precurved CI electrode arrays. The aims here were to investigate 1-year postoperative speech recognition, intraoperative electrically evoked compound action potentials (ECAPs), and their possible relation in patients implanted with a CI532 or its predecessor CI512. Methods: A retrospective analysis of data from 63 patients subjected to cochlear implantation at the Karolinska University Hospital, Sweden, was performed. Speech recognition of the implanted ear was evaluated using phonemically balanced monosyllabic Swedish words at 65 d
B SPL. ECAPs were evaluated using the intraoperative ECAP threshold across ≥8 electrodes generated by the automated neural response telemetry of the CI. Results: The median aided speech recognition score (SRS) 1 year after implantation was 52% (quartile 1 = 40%, quartile 3 = 60%, n = 63) and did not differ statistically significantly between patients with CI512 (n = 38) and CI532 (n = 25). The mean ECAP threshold was 188 CL (current level; SD = 15 CL, n = 54) intraoperatively and did not differ statistically significantly between patients with CI512 (n = 32) and CI532 (n = 22), but the threshold for each electrode varied more between patients with a CI512 (p #x3c; 0.0001). A higher mean ECAP threshold was associated with a worse SRS (Spearman’s ρ = –0.46, p = 0.0004, n = 54). The association remained among those with a CI512 (Spearman’s ρ = –0.62, p = 0.0001, n = 32) when stratified by CI electrode array. Conclusion: No statistically significant difference in speech recognition 1 year after cochlear implantation or in mean threshold of ECAP intraoperatively was found between patients with a CI512 and the more recent, slim CI532, but the ECAP thresholds varied more between those with a CI512. A statistically significant association between SRS and mean ECAP threshold was found, but stratified analysis suggests that the association may be true only for patients with a CI512.
Audiol Neurotol

Synergistic Ototoxicity of Gentamicin and Low-Dose Irradiation: Molecular Basis and Clinical Significance

13-12-2019 – WK Low,SW Teng,MGK Tan

Journal Article

Background: Inner ear structures may be included in the radiation fields when irradiation is used to treat patients with head and neck cancers. These patients may also have concurrent infections that require gentamicin treatment. Radiation and gentamicin are both potentially ototoxic, and their combined use has been shown to result in synergistic ototoxicity in animals. Objective: We aimed to confirm the synergistic ototoxicity of combined gentamicin and low-dose irradiation treatment and identify the underlying molecular mechanisms using an in vitro model. Method: We compared the ototoxic effects of gentamicin, low-dose irradiation, and their combination in the OC-k3 mouse cochlear cell line using cell viability assay, live/dead stain, apoptosis detection assay, oxidative stress detection, and studied the molecular mechanisms involved using immunoblot analysis. Results: Combined treatment led to prolonged oxidative stress, reduced cell viability, and synergistic apoptosis. Gentamicin induced the concurrent accumulation of LC3b-II and SQSTM1/p62, suggesting an impairment of autophagic flux. Low-dose irradiation induced transient p53 phosphorylation and persistent Akt phosphorylation in response to DNA damage. In combined treatment, gentamicin attenuated irradiation-induced Akt activation. Conclusions: Besides increased oxidative stress, synergistic apoptosis observed in combined treatment could be attributed to gentamicin-induced perturbation of autophagic flux and attenuation of Akt phosphorylation, which led to an impairment of radiation-induced DNA repair response.
Audiol Neurotol

Treatment Outcome of Auditory and Frontal Dual-Site rTMS in Tinnitus Patients and Changes in Magnetoencephalographic Functional Connectivity after rTMS: Double-Blind Randomized Controlled Trial

12-12-2019 – TS Noh,JS Kyong,MK Park,JH Lee,SH Oh,CK Chung,JS Kim,MW Suh

Journal Article

Background: Recently, the role of neural modulation in nonauditory cortices via repetitive transcranial magnetic stimulation (r
TMS) for tinnitus control has been emphasized. It is now more compelling to consider these nonauditory cortices and the whole “tinnitus network” as targets for tinnitus treatment to achieve a better outcome. Objective: We aimed to investigate the effects of active dual-site r
TMS treatment in tinnitus reduction using a double-blind randomized controlled trial. Method: In study 1, the dual-site r
TMS treatment group (n = 17) was treated daily for 4 consecutive days. The sham group (n = 13) also visited the clinic for 4 days; they received sham treatment for the same duration as the dual-site r
TMS treatment group. In study 2, the r
TMS treatment protocol was exactly the same as in study 1. Magnetoencephalography recordings were performed before and 1 week after the last r
TMS treatment. The outcome measure was the Tinnitus Handicap Inventory (THI) score and the visual analog scale score. The effects of treatment were assessed 1, 2, 4, and 8 weeks after r
TMS treatment in study 1. Then the mean band power and network changes were compared between pre- and post-treatment values after r
TMS in study 2. Result: Patients in the dual-site r
TMS treatment group exhibited significantly improved THI scores at 2, 4, and 8 weeks after r
TMS treatment compared with the pretreatment scores. However, the sham group did not show any significant reduction in THI scores. When the mean band power changes were compared between pre- and post-treatment assessments, an increased oscillation power was observed in the alpha band after r
TMS. Conclusion: A beneficial effect of r
TMS on tinnitus suppression was found in the dual-site active r
TMS group, but not in the sham r
TMS group.
Audiol Neurotol

Bilateral Vestibular Hypofunction in the Time of the Video Head Impulse Test

11-12-2019 – N Pérez-Fernández,L Alvarez-Gomez,R Manrique-Huarte

Journal Article

Objectives: Bilateral vestibulopathy is a clinical syndrome in which laboratory testing plays a crucial diagnostic role. We aimed to establish the frequency of detection of that finding in a tertiary level hospital considering the new methods of laboratory vestibular examination nowadays in use, with respect to the conventional caloric and rotatory chair test approaches. Design: Two similar time periods (5 years) were retrospectively evaluated, and the demographic, clinical data and test results from 4,576 patients were reviewed. In the first period, the diagnosis was based on caloric and rotatory chair tests and, in the second, on the video head impulse test. Results: Of the patients included, 3.77% in the first period and 4.58% in the second met the criteria for bilateral vestibular hypofunction; there was no significant difference between both periods. Conclusions: The functional vestibular evaluation to detect bilateral deficiency makes no significant difference to the number of patients diagnosed with a bilateral vestibulopathy. New diagnostic categories probably depend not only on the availability and accessibility of complete vestibular and visual-vestibular evaluation, but also on recent advances in defining vestibular disorders. Bilateral vestibular hypofunction manifests with very different patterns. Progress in more detailed definition (clinical and laboratory) is needed, in particular when all 6 semicircular canals and both maculae are available for testing.
Audiol Neurotol

Chronic Electrical Stimulation of the Otolith Organ: Preliminary Results in Humans with Bilateral Vestibulopathy and Sensorineural Hearing Loss

04-12-2019 – A Ramos Macias,A Ramos de Miguel,I Rodriguez Montesdeoca,S Borkoski Barreiro,JC Falcón González

Journal Article

Introduction: Bilateral vestibulopathy is an important cause of imbalance that is misdiagnosed. The clinical management of patients with bilateral vestibular loss remains difficult as there is no clear evidence for an effective treatment. In this paper, we try to analyze the effect of chronic electrical stimulation and adaptation to electrical stimulation of the vestibular system in humans when stimulating the otolith organ with a constant pulse train to mitigate imbalance due to bilateral vestibular dysfunction (BVD). Methods: We included 2 patients in our study with BVD according to Criteria Consensus of the Classification Committee of the Bárány Society. Both cases were implanted by using a full-band straight electrode to stimulate the otoliths organs and simultaneously for the cochlear stimulation we use a perimodiolar electrode. Results: In both cases Vestibular and clinical test (video head impulse test, videonistagmography cervical vestibular evoked myogenic potentials, cVEMP and oVEMP), subjective visual vertical test, computerized dynamic posturography, dynamic gait index, Time UP and Go test and dizziness handicap index) were performed. Posture and gait metrics reveal important improvement if compare with preoperartive situation. Oscillopsia, unsteadiness, independence and quality of life improved to almost normal situation. Discussion/Conclusion: Prosthetic implantation of the otolith organ in humans is technically feasible. Electrical stimulation might have potential effects on balance and this is stable after 1 year follow-up. This research provides new possibilities for the development of vestibular implants to improve gravito-inertial acceleration sensation, in this case by the otoliths stimulation.
Audiol Neurotol

Effects of Glycerol Test on Resonance Frequency in Patients with Ménière’s Disease

12-11-2019 – I Oz,E Hizal,OH Cam,LN Ozluoglu

Journal Article

Objective: To evaluate resonance frequency (RF) values via dehydration effects in the inner ear caused by the glycerol test, which is used as a diagnostic method for Ménière’s disease (MD). Methods: Twenty adult patients with unilateral MD were included in the study. Before, and then at 1, 2, and 3 h after administration of glycerol (1 g/kg), pure-tone hearing levels (125–8,000 k
Hz) and multifrequency tympanometry tests were performed. As a control, the RF values of the ears of 25 healthy subjects (i.e., 50 ears) were compared to the affected and unaffected ears in the 20 MD patients. Results: There was a significant difference between the RF values of affected and healthy ears before glycerol administration (p = 0.047). The RF values before and after glycerol administration into affected ears were compared. The average RF values decreased significantly from 748.0 ± 402.1 to 808.0 ± 410.1 Hz at 1 h after glycerol intake, and this value increased during the subsequent hours. There were no statistically significant differences between the pure-tone levels before and 1 h after glycerol administration, but a significant decrease was observed at 3 h. Conclusion: We suggest that MD has different inner-ear dynamics and normal RF values when compared to healthy ears. Furthermore, decreased inner ear pressure causes reduction of the mass effect and a stiffening of the annular ligament. We conclude that pre- and post-RF tests should be added to the test battery for diagnosis of MD.
Audiol Neurotol

Erratum

07-11-2019 –

Audiol Neurotol 2019;24:270

BalanCI: Head-Referenced Cochlear Implant Stimulation Improves Balance in Children with Bilateral Cochleovestibular Loss

01-11-2019 – NE Wolter,KA Gordon,JL Campos,LD Vilchez Madrigal,DD Pothier,CO Hughes,BC Papsin,SL Cushing

Journal Article

Introduction: To determine the impact of a head-referenced cochlear implant (CI) stimulation system, Balan
CI, on balance and postural control in children with bilateral cochleovestibular loss (BCVL) who use bilateral CI. Methods: Prospective, blinded case-control study. Balance and postural control testing occurred in two settings: (1) quiet clinical setting and (2) immersive realistic virtual environment (Challenging Environment Assessment Laboratory CEAL, Toronto Rehabilitation Institute). Postural control was assessed in 16 and balance in 10 children with BCVL who use bilateral CI, along with 10 typically developing children. Children with neuromotor, cognitive, or visual deficits that would prevent them from performing the tests were excluded. Children wore the Balan
CI, which is a head-mounted device that couples with their CIs through the audio port and provides head-referenced spatial information delivered via the intracochlear electrode array. Postural control was measured by center of pressure (COP) and time to fall using the Wii
TM (Nintendo, WA, USA) Balance Board for feet and the Balan
CI for head, during the administration of the Modified Clinical Test of Sensory Interaction in Balance (CTSIB-M). The COP of the head and feet were assessed for change by deviation, measured as root mean square around the COP (COP-RMS), rate of deviation (COP-RMS/duration), and rate of path length change from center (COP-velocity). Balance was assessed by the Bruininks-Oseretsky Test of Motor Proficiency 2, balance subtest (BOT-2), specifically, BOT-2 score as well as time to fall/fault. Results: In the virtual environment, children demonstrated more stable balance when using Balan
CI as measured by an improvement in BOT-2 scores. In a quiet clinical setting, the use of Balan
CI led to improved postural control as demonstrated by significant reductions in COP-RMS and COP-velocity. With the use of Balan
CI, the number of falls/faults was significantly reduced and time to fall increased. Conclusions: Balan
CI is a simple and effective means of improving postural control and balance in children with BCVL who use bilateral CI. Balan
CI could potentially improve the safety of these children, reduce the effort they expend maintaining balance and allow them to take part in more complex balance tasks where sensory information may be limited and/or noisy.
Audiol Neurotol

Is Early Cochlear Implant Device Activation Safe for All on-the-Ear and off-the-Ear Sound Processors?

30-10-2019 – MO Batuk,M Yarali,BC Cinar,AP Kocabay,MD Bajin,G Sennaroglu,L Sennaroglu

Journal Article

Background: Cochlear implantation (CI) is an effective treatment option for patients with severe-to-profound hearing loss. When CI first started, it was recommended to wait until at least 4 weeks after the CI surgery for the initial activation because of possible complications. Advances in the surgical techniques and experiences in fitting have made initial activation possible within 24 h. Objectives: To compare the complaints and complications after early activation between behind-the-ear (BTE) and off-the-ear (OTE) sound processors and to show the impact of early activation on the electrode impedance values. Method: CI surgeries performed between March 2013 and July 2018 were retrospectively analyzed from the database. In total, 294 CI users were included in the present study. The impedance measurements were analyzed postoperatively at the initial activation prior to the stimulation, and 4 weeks after the initial activation in the first-month follow-up visit. A customized questionnaire was administered in the first-month follow-up fitting session to caregivers and/or patients who were using CI at least for 6 months. Medical records were also reviewed to identify any postoperative complications. Results: In the early activation group, impedance values were significantly lower than in the control group (p #x3c; 0.05) at first fitting. At the first-month follow-up, no significant difference was found between the groups (p #x3e; 0.05). The most common side effects were reported to be edema (6.1%) and pain (5.7%) in the early activation group. In patients with OTE sound processors, the rate of side effects such as skin infection, wound swelling, skin hyperemia, and pain was higher than in patients with BTE sound processors; however, a statistical significance was only observed in wound swelling (p = 0.005). Selecting the appropriate magnet was defined as a problem for the OTE sound processors during the initial activation. Conclusion: This study revealed that early activation of CI was clinically safe and feasible in patients with BTE sound processors. When using OTE sound processors, the audiologists should be careful during the activation period and inform patients of possible side effects. The first fitting should be delayed for 4 weeks after CI for OTE sound processors. This current study is the first to report this finding with 5 years of experience in a large cohort.
Audiol Neurotol

Cochlear Dead Regions in Sporadic Unilateral Vestibular Schwannomas Using the Threshold-Equalizing Noise Test

30-10-2019 – H Byun,YS Cho,SH Hong,IJ Moon

Journal Article

Background: Vestibular schwannoma (VS) is a benign intracranial neoplasm originating in the Schwann cells of the vestibular nerve. Despite its origin, the most common symptom is sensorineural hearing loss which is presented in more than 90% of patients. The underlying pathophysiology of this hearing loss has not been fully understood. Objective: To assess the in vivo function of cochlear inner hair cells and spiral ganglion neurons in VS, cochlear dead regions (DRs) were evaluated via the threshold-equalizing noise (TEN) test in untreated VS patients. Method: Untreated patients diagnosed with sporadic unilateral VS and normal contralesional hearing were enrolled from July 2011 to June 2016. Audiometric evaluation including TEN tests were performed. Based on the magnetic resonance findings, characteristics of individual tumors were assessed. Results: The average pure-tone threshold (word recognition score WRS) of 23 enrolled patients was 42.7 d
B (76.1%). Nineteen DRs (11.8% of 161 tested frequencies) were found in 8 patients (34.8% of enrolled cases). Among the intracanalicular (IAC) tumors, 6 out of 10 ears (60%) carried DRs, while 2 of 13 (15.4%) showed DRs among the cerebellopontine angle (CPA) lesions (p = 0.039). Pure-tone thresholds and WRS were not different between the two groups. Logistic regression analysis showed that the tumor location, IAC versus CPA, was significantly associated with DRs (p = 0.041, Nagelkerke R2 = 0.471), whereas age, sex, tumor size, distance from the tumor to the cochlea, T2-weighted hypointensity on the MRI and pure-tone thresholds showed no significance. Conclusions: Cochlear DRs are detected in hearing losses associated with unilateral sporadic VS using the TEN test. Individual DRs were detected variously in high, mid, or low frequencies. In our preliminary data, IAC tumors showed a higher number of DRs than CPA tumors despite similar average hearing thresholds. Further studies including longitudinal follow-up of hearing as well as change in DRs may provide useful information about VS patients.
Audiol Neurotol