Dorothe Veraguth

Subjective and objective results after bilateral cochlear implantation in adults.

Objective: To assess and compare subjective and objective results after bilateral cochlear implantation with a special emphasis on time interval between the first and second implant. Study Design: Clinical trial. Setting: Tertiary referral center. Patients: All consecutively bilaterally implanted adult patients who had used the second implant for more than 6 months were selected for the study. They had to have the mental capacity to answer questions regarding their hearing abilities and fill out a questionnaire (n = 34). Twenty-nine patients (85%) finally could be included in the study (age at first implantation, 31.0 ± 16 yr [mean ± standard deviation {SD}], time to second implantation, 5.6 ± 5.7 yr [mean ± SD]). In all patients, a full insertion (21 electrodes) of the implant was achieved. For the subjective part of the study, the patients were matched with unilaterally implanted subjects selected according to specified criteria. Interventions: Sequential or simultaneous cochlear implantation with a Nucleus device. Main Outcome Measures: Speech comprehension measures were performed using the Oldenburger sentences in quiet and in noise with unilateral and bilateral implant use. Summation effect, head shadow effect, squelch effect, and interaural difference in quiet and noise were calculated. Advantage for binaural stimulation with respect to the unilateral condition was assessed for each individual. Additionally, a localization test was performed using 12 speakers arranged in a circle. Subjective benefit was assessed by a questionnaire (The Speech, Spatial and Qualities of Hearing Scale). Results were analyzed with special emphasis on effects of timing and intervals. Results: There was a statistically significant advantage for the head shadow effect test (p < 0.05) when the sound source was located on the activated side. There was also a statistically significant correlation of the subjective and objective results and a strong correlation of the interaural difference of speech intelligibility in quiet and the time interval between the first and the second implant (p < 0.001; r2 = 55%). In the bi-implanted state, an interaural difference of 18 ± 27% and 3 ± 2.2 dB signal-to-noise ratio (mean ± SD) was measured in quiet and noise, respectively. The mean results for the bilateral condition for the summation effect, the squelch effect, and speech discrimination in quiet were better than in the unilateral condition but were not statistically significant. The subjective results of the bilateral group were better in all categories than the results of the unilateral group but were just below statistical significance. Conclusion: Speech understanding in noise is improved with bilateral cochlear implantation with unambiguous evidence that the second implant expands the sound field for effective speech recognition. Communication in daily life is facilitated, as determined by the subjective Speech, Spatial and Qualities of Hearing Scale test. The correlation of the subjective and objective results confirms the practical benefits in daily activities. Although there was improvement with a second Cochlear implant even after a long implantation interval, short intervals lead to better results.

A new implantable middle ear hearing device for mixed hearing loss: A feasibility study in human temporal bones

Hypothesis: To assess the feasibility of a new, active middle ear device in temporal bones (TB). Background: This device is designed for patients with mixed hearing loss subsequent to chronic middle ear infection, surgery, or trauma. This Bell-Vibroplasty is built from a VIBRANT MED-EL Vibrant Soundbridge and a Kurz Bell titanium partial ossicular replacement prosthesis. Methods: In three fresh TBs, healthy and reconstructed middle ears were analyzed by means of laser Doppler interferometry. The sound transmission properties of a partial ossicular replacement prosthesis and a passive and an active Bell-Vibroplasty were compared with healthy middle ear function. Results: The measurements provided reliable results with small standard deviations and good signal-to-noise ratios. The performance levels of the partial ossicular replacement prosthesis and of the passive Bell-Vibroplasty were comparable with that of healthy middle ear function. The activated Bell-Vibroplasty provided linear function and a flat frequency response within the measured frequency range (500 Hz-8 kHz), with peak deviations of less than 10 dB. The maximum output of the Bell-Vibroplasty was equivalent to 125-dB sound pressure level. Conclusion: Bell-Vibroplasty is feasible in TBs. Bell-Vibroplasty performance in TBs is sufficient to allow for a clinical trial as a next step.

Tight stapes prosthesis fixation leads to better functional results in otosclerosis surgery.

Tight fixation of stapes prostheses yields better functional results because sound transmission from the incus to the prosthesis is improved. Background: The optimal prosthesis to use for otosclerosis surgery is still a matter of debate. It has been proposed that using prostheses made of Nitinol, a shape-memory metal, produces better functional results with less variability and reduced risk for middle and inner ear damage. This is thought to be because heat activation rather than manual crimping of the prosthesis loop forms a tighter fixation. Methods: Functional results of two groups were compared 1 year after surgery. In one group were 75 cases of stapedotomy performed using Nitinol prostheses. Results were analyzed prospectively and compared with 75 retrospectively analyzed matched controls with conventional stapes prostheses. Crimping quality was measured in 23 patients by intraoperative laser Doppler interferometry (LDI). Causality was assessed by correlating results of intraoperative LDI and postoperative pure-tone thresholds. Results: Nitinol and conventional prostheses yielded postoperative air-bone gaps (ABGs) of 8.0 and 11.6 dB with 71 and 43% ABG closure within 10 dB, respectively. Intraoperatively, sound transmission was improved by 2.5 dB with the Nitinol prostheses as compared with conventional prostheses. These differences were statistically significant. Intraoperative fixation quality was positively correlated to functional outcome, but results were not statistically significant. Conclusion: Tight fixation, as provided by Nitinol prostheses leads to improved functional results because of better sound transmission properties at the incus-prosthesis interface. The improvement in ABG closure is in the range of 3 dB pure-tone average and more pronounced at higher frequencies. Nitinol prostheses provide an effective treatment option in otosclerosis surgery.

Functional Results and Subjective Benefit of a Transcutaneous Bone Conduction Device in Patients With Single-Sided Deafness.

Objective To analyze speech discrimination scores and subjective benefit of a transcutaneous bone conduction device (tBCD) in adults with single-sided deafness (SSD). Study Design Prospective cohort study. Setting Tertiary referral center. Patients Nine adults with SSD for more than 1 year and normal hearing on the contralateral side (PTA <30 dB HL) were implanted with a tBCD. Interventions Transmastoidal implantation of a Bonebridge (BB, MED-EL) tBCD. Main Outcome Measures Aided and unaided speech discrimination scores in three different spatial settings were measured using the Oldenburg sentence test (OLSA). Quality of life was assessed by two questionnaires, the Bern Benefit in Single Sided Deafness Questionnaire (BBSS) and the Speech, Spatial and Qualities of Hearing scale for benefit questionnaire (SSQ-B). Results Speech discrimination scores measured by OLSA showed a mean signal-to-noise ratio improvement of 1.7 dB SPL for the aided condition compared with the unaided condition in the setting where the sound signal is presented on the side of the implanted ear and the noise is coming from the front (p < 0.05). In the other two settings (signal and noise from front; signal from normal hearing ear and noise from front), the signal-to-noise ratio did not change significantly. This benefit became manifest after 6 months. Good satisfaction was indicated by positive results on the questionnaires. Conclusion Speech discrimination in noise for patients implanted with the BB is comparable with patients with other bone conduction hearing aids. A learning curve is clearly detectable. The subjective benefit was rated positively by the patients. With the advantage of intact skin conditions after implantation, the BB is an adequate option for patients with SSD.

Assessment of Cochlear Trauma During Cochlear Implantation Using Electrocochleography and Cone Beam Computed Tomography.

Objective: To assess cochlear trauma during cochlear implantation by electrocochleography (ECoG) and cone beam computed tomography (CBCT) and to correlate intraoperative cochlear trauma with postoperative loss of residual hearing. Methods: ECoG recordings to tone bursts at 250, 500, 750, and 1000 Hz and click stimuli were recorded before and after insertion of the cochlear implant electrode array, using an extracochlear recording electrode. CBCTs were conducted within 6 weeks after surgery. Changes of intraoperative ECoG recordings and CBCT findings were correlated with postoperative threshold shifts in pure-tone audiograms. Results: Fourteen subjects were included. In three subjects a decrease of low-frequency ECoG responses at 250, 500, 750, and 1000 Hz occurred after insertion of the electrode array. This was associated with no or minimal residual hearing 4 weeks after surgery. ECoG responses to click stimuli were present in six subjects and showed a decrease after insertion of the electrode array in three. This was associated with a mean hearing loss of 21 dB in postoperative pure-tone audiograms. Scalar dislocation of the electrode array was assumed in one subject because of CBCT findings and correlated with a decrease of low-frequency ECoG responses and a complete loss of residual hearing. Conclusion: Hearing loss of ⩽11 dB is not associated with detectable decrease in ECoG recordings during cochlear implantation. However, in a majority of patients with threshold shifts of >11 dB or complete hearing loss, an intraoperative decrease of high- or low-frequency ECoG signals occurs, suggesting acute cochlear trauma.

Chudley-McCullough syndrome: case report and review of the neuroimaging spectrum.

We report on a child with Chudley-McCullough syndrome and re-evaluate the spectrum of imaging findings (in 15 previously reported patients) which appear to be variable and, to some extent, ambiguous in the literature. Magnetic resonance imaging of the brain revealed asymmetric colpocephaly with agenesis of the splenium corporis callosi, ribbon-like subcortical gray matter heterotopia along the cingulate gyri, malrotation of both hippocampi, and dysplasia of the cerebellum. Macrocrania together with sensorineural hearing loss, colpocephaly, and posterior or complete agenesis of the corpus callosum can be considered the hallmarks of the autosomal recessive Chudley-McCullough syndrome. These may be variably associated with interhemispheric arachnoid cyst, cortical dysplasia, gray matter heterotopia, and cerebellar dysplasia. While early support with hearing aids may lead to improved language and cognitive outcome, shunting of ventricular dilatation is not indicated in the Chudley-McCullough syndrome.

Hearing Preservation After Cochlear Implantation May Improve Long-term Word Perception in the Electric-only Condition.

Objective: To correlate hearing preservation with word perception in the electric-only condition in recipients of full length cochlear implant (CI) electrode arrays. Study Design: Retrospective chart review. Setting: Tertiary academic referral center. Patients: CI recipients between January 2003 and December 2013 who had measurable residual acoustic hearing before surgery and serial postoperative word perception tests. Intervention: Demographic data, pre- and postoperative pure-tone average, and postoperative monosyllabic word perception scores were evaluated. Main Outcome Measure: Hearing preservation was correlated with postoperative monosyllabic word perception scores. Results: Data from 96 ears in 91 subjects were included. Complete or partial hearing preservation was achieved in 48%. After 6 and 12 months, no significant difference in word perception was found between subjects with and without hearing preservation. However, after 18 or more months, subjects with hearing preservation had significantly better word perception scores (83% versus 72%, p <0.05). Conclusion: Preservation of residual hearing leads to better word perception in the electric-only condition over the long term. CI recipients with hearing preservation continue to make progress after more than 12 months of CI experience whereas those without plateau at 12 months.

Audiological monitoring in Swiss childhood cancer patients

Full audiological monitoring is the best strategy to detect hearing loss early and to provide timely intervention in the absence of a clinical method of otoprotection. Full monitoring requires audiological evaluation before, and then during and after ototoxic cancer treatment. In a worldwide context of monitoring protocols that vary substantially, we analyzed the audiological monitoring of childhood cancer patients over the last decade across treatment centers in Switzerland.

Assessment of Cochlear Function during Cochlear Implantation by Extra- and Intracochlear Electrocochleography

Objective: The aims of this study were: (1) To investigate the correlation between electrophysiological changes during cochlear implantation and postoperative hearing loss, and (2) to detect the time points that electrophysiological changes occur during cochlear implantation. Material and Methods: Extra- and intracochlear electrocochleography (ECoG) were used to detect electrophysiological changes during cochlear implantation. Extracochlear ECoG recordings were conducted through a needle electrode placed on the promontory; for intracochlear ECoG recordings, the most apical contact of the cochlear implant (CI) electrode itself was used as the recording electrode. Tone bursts at 250, 500, 750, and 1000 Hz were used as low-frequency acoustic stimuli and clicks as high-frequency acoustic stimuli. Changes of extracochlear ECoG recordings after full insertion of the CI electrode were correlated with pure-tone audiometric findings 4 weeks after surgery. Results: Changes in extracochlear ECoG recordings correlated with postoperative hearing change (r = −0.44, p = 0.055, n = 20). Mean hearing loss in subjects without decrease or loss of extracochlear ECoG signals was 12 dB, compared to a mean hearing loss of 22 dB in subjects with a detectable decrease or a loss of ECoG signals (p = 0.0058, n = 51). In extracochlear ECoG recordings, a mean increase of the ECoG signal of 4.4 dB occurred after opening the cochlea. If a decrease of ECoG signals occurred during insertion of the CI electrode, the decrease was detectable during the second half of the insertion. Conclusion: ECoG recordings allow detection of electrophysiological changes in the cochlea during cochlear implantation. Decrease of extracochlear ECoG recordings during surgery has a significant correlation with hearing loss 4 weeks after surgery. Trauma to cochlear structures seems to occur during the final phase of the CI electrode insertion. Baseline recordings for extracochlear ECoG recordings should be conducted after opening the cochlea. ECoG responses can be recorded from an intracochlear site using the CI electrode as recording electrode. This technique may prove useful for monitoring cochlear trauma intraoperatively in the future.

Vestibulo-cochlear function in inflammatory neuropathies

OBJECTIVE We aimed to quantify peripheral-vestibular deficits that may contribute to imbalanced stance/gait in patients with inflammatory neuropathies. METHODS Twenty-one patients (58 ± 15 y [mean age ± 1SD]; chronic-inflammatory-demyelinating-polyneuropathy = 10, Guillain-Barré Syndrome = 5, Anti-MAG peripheral neuropathy = 2, multifocal-motor-neuropathy = 4) were compared with 26 healthy controls. All subjects received video-head-impulse testing (vHIT), caloric irrigation and cervical/ocular vestibular-evoked myogenic-potentials (VEMPs). The Yardley vertigo-symptom-scale (VSS) was used to rate vertigo/dizziness. Postural stability was assessed using the functional gait-assessment (FGA). Pure-tone audiograms (n = 18), otoacoustic emissions (n = 12) and auditory brainstem responses were obtained (n = 12). RESULTS Semicircular-canal hypofunction was noted in 9/21 (43%) patients (vHIT = 6; caloric irrigation = 5), whereas otolith function was impaired in 12/21 (57%) (oVEMPs = 8; cVEMPs = 5), resulting in vestibular impairment of at least one sensor in 13/21 (62%). On average, 2.4 ± 1.1 vestibular end organs (each side: anterior/posterior/horizontal canal, utriculus, sacculus; total = 10) were affected. The VSS-scores were higher in patients (16.8 ± 8.6 vs. 9.5 ± 6.2, p = 0.002) but did not correlate with the number of affected organs. Auditory neuropathy was found in 1/12 (8%) patients. CONCLUSION Impairment of one or more vestibular end organs was frequent, but usually mild, possibly contributing to imbalance of stance/gait in inflammatory neuropathies. SIGNIFICANCE While our data does not support routine vestibular testing in inflammatory neuropathies, this may be considered in selected cases.