Search Results (11)

The varicella-zoster virus (VZV), a member of the Herpesviridae family, causes both the initial varicella infection and subsequent zoster episodes. Disorders of the eighth cranial nerve are common in people with herpes zoster oticus (HZO). We performed a review of the literature on different databases including PubMed and SCOPUS, focusing on cochlear and vestibular symptoms; 38 studies were considered in our review. A high percentage of cases of HZO provokes cochlear and vestibular symptoms, hearing loss and vertigo, whose onset is normally preceded by vesicles on the external ear. It is still under debate if the sites of damage are the inferior/superior vestibular nerves and cochlear nerves or a direct localization of the infection in the inner ear. The involvement of other contiguous cranial nerves has also been reported in a few cases. We report the case of a patient with single-side HZO presenting clinical manifestations of cochleo-vestibular damage without neurological and meningeal signs; after 15 days, the patient developed a new episode of vertigo with clinical findings of acute contralateral vestibular loss. To our knowledge, only three other such cases have been published. An autoimmune etiology may be considered to explain these findings. Full article

Objectives: In the absence of binaural hearing, individuals with single-sided deafness can adapt to use monaural level and spectral cues to improve their spatial hearing abilities. Contralateral routing of signal is the most common form of rehabilitation for individuals with single-sided deafness. However, little is known about how these devices affect monaural localization cues, which single-sided deafness listeners may become reliant on. This study aimed to investigate the effects of contralateral routing of signal hearing aids on localization performance in azimuth and elevation under monaural listening conditions. Design: Localization was assessed in 10 normal hearing adults under three listening conditions: (1) normal hearing (NH), (2) unilateral plug (NH-plug), and (3) unilateral plug and CROS aided (NH-plug + CROS). Monaural hearing simulation was achieved by plugging the ear with E-A-Rsoft™ FX™ foam earplugs. Stimuli consisted of 150 ms high-pass noise bursts (3–20 kHz), presented in a random order from fifty locations spanning ±70° in the horizontal and ±30° in the vertical plane at 45, 55, and 65 dBA. Results: In the unilateral plugged listening condition, participants demonstrated good localization in elevation and a response bias in azimuth for signals directed at the open ear. A significant decrease in performance in elevation occurs with the contralateral routing of signal hearing device on, evidenced by significant reductions in response gain and low r² value. Additionally, performance in azimuth is further reduced for contralateral routing of signal aided localization compared to the simulated unilateral hearing loss condition. Use of the contralateral routing of signal device also results in a reduction in promptness of the listener response and an increase in response variability. Conclusions: Results suggest contralateral routing of signal hearing aids disrupt monaural spectral and level cues, which leads to detriments in localization performance in both the horizontal and vertical dimensions. Increased reaction time and increasing variability in responses suggests localization is more effortful when wearing the contralateral rerouting of signal device. Full article

Background: Cochlear implantation (CI) following endoscopic transcanal infrapromontorial vestibular schwannoma (VS) dissection is a feasible intervention in intracanalicular VS, with minimal extension into the cerebellopontine angle, but no audiologic results have ever been reported in the literature. Methods: From 2015 to 2021 in the Otorhynolaryngology Departments of Modena and Verona, three patients underwent this intervention. All were suffering from sporadic left-sided intracanalicular Koos I VS. Intraoperative electrically evoked auditory brainstem responses and electrophysiological measurements were performed before and after the placement of the electrode array, respectively. Since device activation one month after the surgery, each patient was followed up with audiometric tests, data logging, electrode impedance measurements and neural response telemetry performed at each scheduled fitting session at 15 days and 3, 6, 12 and 24 months. Results: Only in patient No. 3, an auditory benefit was observed and still evident even 36 months after activation. Impedances increased progressively in patient No. 1 and a benefit was never reported. Patient No. 2 left the follow-up for worsening comorbidities. Conclusions: CI following transcanal infrapromontorial VS resection is a beneficial intervention. The residual cochlear nerve after the tumour dissection and the course of electrophysiological measurements in the postoperative period were the main predictive factors for audiological outcomes. Full article

The purpose of the study was to measure the variability of transiently evoked otoacoustic emissions (TEOAEs) and the medial olivocochlear reflex (MOCR) over a long period of time in one person. TEOAEs with and without contralateral acoustic stimulation (CAS) by white noise were measured, from which MOCR strength could be derived as either a dB or % change. In this longitudinal case study, measurements were performed on the right and left ears of a young, normally hearing adult female once a week for 1 year. The results showed that TEOAE level and MOCR strength fluctuated over the year but tended to remain close to a baseline level, with standard deviations of around 0.5 dB and 0.05 dB, respectively. The TEOAE latencies at frequencies from 1 to 4 kHz were relatively stable, with maximum changes ranging from 0.5 ms for the 1 kHz band to 0.08 ms for the 4 kHz band. TEOAE levels and MOCR strengths were strongly and negatively correlated, meaning that the higher the TEOAE level, the lower the MOCR. Additionally, comparison of fluctuations between the ears revealed positive correlation, i.e., the higher the TEOAE level or MOCR in one ear, the higher in the second ear. Full article

Objectives—Cochlear implantation has been suggested to be associated with an air-bone gap, possibly secondary to increased middle- and inner-ear stiffness. To explore the effect of possible changes in mechanics due to cochlear implantation, we measured wideband tympanometry (WBT) in individuals with normal hearing and individuals with severe to profound sensorineural hearing loss who underwent unilateral or bilateral cochlear implantation. Our goal was to characterize differences in WBT patterns associated with severe to profound sensorineural hearing loss and with cochlear implantation. Design—The study participants were 24 individuals with normal hearing (48 ears) and 17 with cochlear implants, of which 15 were unilaterally implanted and two were implanted bilaterally. All the participants had normal otoscopy. In the implanted group, inner-ear anatomy was normal according to preoperative imaging. All participants underwent pure-tone audiometric assessment, standard tympanometry (226 Hz probe tone), and WBT to a click stimulus (analyzed from 226 to 8000 Hz). WBT was recorded at ambient and peak pressures. To elucidate the effect of sensorineural hearing loss on WBT, we compared normal-hearing ears with impaired non-implanted ears. The impact of cochlear implantation was assessed by comparing the WBT of the implanted and non-implanted ears of the same participants. Moreover, the effect of the ear (right vs. left) and test–retest reproducibility were evaluated. Results—WBT results for right and left ears showed no statistically significant differences in the normal hearing participants. There were no statistical differences shown between repeated measurements of WBT with removal and re-insertion of the probe in any of the groups—the normal ears, the implanted ears, and the non-implanted ears with hearing impairment. Peak compensated admittance (Ytm) in standard tympanometry was normal in 32 out of 34 (94%) ears with sensorineural hearing loss, with one CI user having bilateral negative middle-ear pressure. Compared to normal-hearing ears, ears with severe to profound SNHL, with or without cochlear implantation, showed a significant decrease in absorbance at high frequencies (4000–5000 Hz). Implanted ears, compared both to normal-hearing and contralateral-non-implanted ears, showed a significant decrease in absorbance at low frequencies (400–800 Hz) and an increase in absorbance around 1600 Hz. Conclusions—WBT analysis revealed that the implanted ears showed a significant decrease in absorbance at low frequencies (400–800 Hz) and an increase at 1600 Hz. This finding is likely a result of an increased stiffness due to the implantation surgery and the presence of the implant in the inner ear. In contrast, the specific decrease in absorbance around 4000–5000 Hz in the implanted and non-implanted ears compared to the normal ears is likely either due to aging or the impact of the severe-to-profound SNHL on the input impedance of the cochlea. The structural and functional changes of both the conductive system and the cochlea associated with aging and SNHL may change the wideband acoustic immittance of the ear and these alterations might be correlated with the hearing loss severity. Additional research is needed to determine how much hearing loss and age influence wideband acoustic immittance of the ear. Full article

The aim of this study was to compare the reliability of the medial olivocochlear reflex (MOCR) between men and women. The strength of the MOCR was measured in terms of the suppression of transiently evoked otoacoustic emissions (TEOAEs) by contralateral acoustic stimulation (CAS). The difference between TEOAEs with and without CAS (white noise) was calculated as raw decibel TEOAE suppression as well as normalized TEOAE suppression expressed in percent. In each subject, sets of measurements were performed twice. Reliability was evaluated by calculating the intraclass correlation coefficient, the standard error of measurement, and the minimum detectable change (MDC). The study included 40 normally hearing subjects (20 men; 20 women). The estimates of MOCR for both genders were similar. Nevertheless, the reliability of the MOCR was poorer in men, with an MDC around twice that of women. This can be only partially attributed to slightly lower signal-to-noise ratios (SNRs) in men, since we used strict procedures calling for high SNRs (around 20 dB on average). Furthermore, even when we compared subgroups with similar SNRs, there was still lower MOCR reliability in men. Full article

The purpose of the study is to gauge the benefits of binaural integration effects (redundancy and squelch) due to preserved low-frequency residual hearing in the implanted ear of cochlear implant users with single-sided deafness. There were 11 cochlear implant users (age 18–61 years old) who had preserved low-frequency hearing in the implanted ear; they had a normal hearing or mild hearing loss in the contralateral ear. Patients were tested with monosyllabic words, under different spatial locations of speech and noise and with the cochlear implant activated and deactivated, in two listening configurations—one in which low frequencies in the implanted ear were masked and another in which they were unmasked. We also investigated how cochlear implant benefit due to binaural integration depended on unaided sound localization ability. Patients benefited from the binaural integration effects of redundancy and squelch only in the unmasked condition. Pearson correlations between binaural integration effects and unaided sound localization error showed significance only for squelch (r = −0.67; p = 0.02). Hearing preservation after cochlear implantation has considerable benefits because the preserved low-frequency hearing in the implanted ear contributes to binaural integration, presumably through the preserved temporal fine structure. Full article

This electrophysiological study investigated the role of the medial olivocochlear (MOC) efferents in listening in noise. Both ears of eleven normal-hearing adult participants were tested. The physiological tests consisted of transient-evoked otoacoustic emission (TEOAE) inhibition and the measurement of cortical event-related potentials (ERPs). The mismatch negativity (MMN) and P300 responses were obtained in passive and active listening tasks, respectively. Behavioral responses for the word recognition in noise test were also analyzed. Consistent with previous findings, the TEOAE data showed significant inhibition in the presence of contralateral acoustic stimulation. However, performance in the word recognition in noise test was comparable for the two conditions (i.e., without contralateral stimulation and with contralateral stimulation). Peak latencies and peak amplitudes of MMN and P300 did not show changes with contralateral stimulation. Behavioral performance was also maintained in the P300 task. Together, the results show that the peripheral auditory efferent effects captured via otoacoustic emission (OAE) inhibition might not necessarily be reflected in measures of central cortical processing and behavioral performance. As the MOC effects may not play a role in all listening situations in adults, the functional significance of the cochlear effects of the medial olivocochlear efferents and the optimal conditions conducive to corresponding effects in behavioral and cortical responses remain to be elucidated. Full article

The Nucleus^® 5 System Sound Processor (CP810, Cochlear^™, Macquarie University, NSW, Australia) contains two omnidirectional microphones. They can be configured as a fixed directional microphone combination (called Zoom) or as an adaptive beamformer (called Beam), which adjusts the directivity continuously to maximally reduce the interfering noise. Initial evaluation studies with the CP810 had compared performance and usability of the new processor in comparison with the Freedom^™ Sound Processor (Cochlear^™) for speech in quiet and noise for a subset of the processing options. This study compares the two processing options suggested to be used in noisy environments, Zoom and Beam, for various sound field conditions using a standardized speech in noise matrix test (Oldenburg sentences test). Nine German-speaking subjects who previously had been using the Freedom speech processor and subsequently were upgraded to the CP810 device participated in this series of additional evaluation tests. The speech reception threshold (SRT for 50% speech intelligibility in noise) was determined using sentences presented via loudspeaker at 65 dB SPL in front of the listener and noise presented either via the same loudspeaker (S₀N₀) or at 90 degrees at either the ear with the sound processor (S₀N_CI+) or the opposite unaided ear (S₀N_CI-). The fourth noise condition consisted of three uncorrelated noise sources placed at 90, 180 and 270 degrees. The noise level was adjusted through an adaptive procedure to yield a signal to noise ratio where 50% of the words in the sentences were correctly understood. In spatially separated speech and noise conditions both Zoom and Beam could improve the SRT significantly. For single noise sources, either ipsilateral or contralateral to the cochlear implant sound processor, average improvements with Beam of 12.9 and 7.9 dB in SRT were found. The average SRT of –8 dB for Beam in the diffuse noise condition (uncorrelated noise from both sides and back) is truly remarkable and comparable to the performance of normal hearing listeners in the same test environment. The static directivity (Zoom) option in the diffuse noise condition still provides a significant benefit of 5.9 dB in comparison with the standard omnidirectional microphone setting. These results indicate that CI recipients may improve their speech recognition in noisy environments significantly using these directional microphone-processing options. Full article

The purpose of this study was to revisit the two-channel, simultaneous click-evoked extratympanic electrocochleography and auditory brainstem response (ECoG/ABR) recording technique for clinical use in normal hearing participants. Recording the compound action potential (AP) of the ECoG simultaneously with ABR may be useful when Wave I of the ABR is small or diminished in patients with sensorineural or retrocochlear disorder and minimizes overall test time. In contrast to some previous studies that used the extratympanic electrode both as non-inverting electrode for the ECoG and inverting electrode for ABR, this study maintained separate recording channel montages unique to conventional click-evoked ECoG and ABR recordings. That is, the ABR was recorded using a vertical channel (Cz to ipsilateral earlobe), while the ECoG with custom extratympanic electrode was recorded using a horizontal channel (tympanic membrane to contralateral earlobe). The extratympanic electrode is easy to fabricate inhouse, or can be purchased commercially. Maintaining the conventional ABR montage permits continued use of traditional normative data. Broadband clicks at a fixed level of 85 dB nHL were presented with alternating polarity at stimulus rates of 9.3, 11.3, and 15.3/s. Different stimulation rates were explored to identify the most efficient rate without sacrificing time or waveform morphology. Results revealed larger ECoG AP than ABR Wave I, as expected, and no significant difference across stimulation rate and no interaction effect. Extratympanic electrode placement takes little additional clinic time and may improve the neurodiagnostic utility of the ABR. Full article

The aim of the study was to establish the extended high frequency thresholds (EHF) of school-age children with no hearing complaints. The study was conducted on 50 children aged 8 to 12 years with pure tone thresholds (0.5, 1 and 2 kHz) of 15 dB HL or less, with normal speech discrimination and tympanometry and with the presence of contralateral acoustic reflexes of 0.5, 1, 2 and 4 kHz. The children were tested for EHF at frequencies of 9, 10, 11.2, 12.5, 14 and 16 kHz. No significant differences were found between the right and left ear for female and male groups. The results allowed us to group the children into a single sample with mean thresholds (dB) of 8.6 (9 kHz), 6.2 (10 kHz), 8.2 (11.2 kHz), 7.1 (12.5 kHz), 0.4 (14 kHz), and -3.6 (16 kHz). We conclude that, for school-age children, the extended EHF below 15 dBHL could be used as an indication of normal hearing sensitivity. Full article