Unilateral Conductive Hearing Loss Research Articles

Binaural hearing in monaural conductive or mixed hearing loss fitted with unilateral Bonebridge.

To determine the benefits of binaural hearing rehabilitation in patients with monaural conductive or mixed hearing loss treated with a unilateral bone conduction implant (BCI). This monocentric study includes 7 patients with monaural conductive or mixed hearing loss who underwent surgical implantation of a unilateral BCI (Bonebridge, Med-El). An ITA Matrix test was performed by each patient included in the study - without and with the BCI and in three different settings - to determine the summation effect, squelch effect and head shadow effect. Subjective hearing benefits were assessed using the Abbreviated Profile of Hearing Aid Benefit (APHAB) questionnaire. The difference in signal to noise ratio of patients without and with BCI was 0.79 dB in the summation setting (p < 0.05), 4.62 dB in the head shadow setting (p < 0.05) and 1.53 dB (p = 0.063) in the squelch setting. The APHAB questionnaire revealed a subjective discomfort in the presence of unexpected sounds in patients using a unilateral BCI (aversiveness score) compared to the same environmental situations without BCI, with a mean discomfort score of 69.00% (SD ± 21.24%) with monaural BCI versus 25.67% (SD ± 16.70%) without BCI (difference: -43.33%, p < 0.05). In terms of global score, patients wearing a unilateral Bonebridge implant did not show any significant differences compared to those without hearing aid (difference: -4.00%, p = 0.310). Our study shows that the use of a unilateral BCI in patients affected by monaural conductive or mixed hearing loss can improve speech perception under noise conditions due to the summation effect and to the decrease of the head shadow effect. However, since monaural BCIs might lead to discomfort under noise conditions in some subjects, a pre-operative assessment of the possible individual benefit of a monaural BCI should be carried out in patients affected by unilateral conductive or mixed hearing loss in order to investigate the possible additional effect of the fitting of hearing aids.

Asymmetry in Cortical Thickness of the Heschl's Gyrus in Unilateral Ear Canal Atresia.

Unilateral congenital conductive hearing impairment in ear canal atresia leads to atrophy of the gray matter of the contralateral primary auditory cortex or changes in asymmetry pattern if left untreated in childhood. Unilateral ear canal atresia with associated severe conductive hearing loss results in deteriorated sound localization and difficulties in understanding of speech in a noisy environment. Cortical atrophy in the Heschl's gyrus has been reported in acquired sensorineural hearing loss but has not been studied in unilateral conductive hearing loss. We obtained T1w and T2w FLAIR MRI data from 17 subjects with unilateral congenital ear canal atresia and 17 matched controls. Gray matter volume and thickness were measured in the Heschl's gyrus using Freesurfer. In unilateral congenital ear canal atresia, Heschl's gyrus exhibited cortical thickness asymmetry (right thicker than left, corrected p = 0.0012, mean difference 0.25 mm), while controls had symmetric findings. Gray matter volume and total thickness did not differ from controls with normal hearing. We observed cortical thickness asymmetry in congenital unilateral ear canal atresia but no evidence of contralateral cortex atrophy. Further research is needed to understand the implications of this asymmetry on central auditory processing deficits.

The Effects of BCDs in Unilateral Conductive Hearing Loss: A Systematic Review.

Bone conduction devices (BCDs) are widely used in the treatment of conductive hearing loss (CHL), but their applications on unilateral CHL (UCHL) patients remain controversial. To evaluate the effects of BCDs in UCHL, a systematic search was undertaken until May 2023 following the PRISMA guidelines. Among the 391 references, 21 studies met the inclusion criteria and were ultimately selected for review. Data on hearing thresholds, speech recognition, sound localization, and subjective questionnaire outcomes were collected and summarized. Moderate hearing threshold improvements were found in UCHL patients aided with BCDs. Their speech recognition abilities improved significantly. However, sound localization results showed wide individual variations. According to subjective questionnaires, BCDs had an overall positive influence on the daily life of UCHL patients, although several unfavorable experiences were reported by some of them. We concluded that the positive audiological benefits and subjective questionnaire results have made BCDs a credible intervention for UCHL patients. Before final implantations, UCHL patients should first go through a period of time when they were fitted with non-implantable BCDs as a trial.

Conductive hearing loss in newborns: Hearing profile, risk factors, and occasions of service.

Infants diagnosed with a conductive hearing loss (CHL) are at increased risk of developmental delays. Using a sample of infants diagnosed with CHL through UNHS, this study aimed to investigate the relationship between specific demographic or clinical characteristics and 1) occasions of service to reach a hearing diagnosis and 2) the profile of CHL. Retrospective analysis was conducted for all infants with CHL born between 01/01/2007 and 31/12/2018 who had received UNHS. Chi squared analysis was conducted on data from 1208 records. Infants with ≥1 risk factor for hearing loss were more likely to attend more than three occasions of service. Infants who were bilateral refer/medical exclusion, Torres Strait Islander, had ≥1 risk factors for hearing loss or were born pre-term had greater proportions of bilateral CHL than unilateral CHL. Mild to moderate was the most frequent degree of CHL, although a unilateral or bilateral CHL did not have an association with the severity of CHL. Compared to other risk factors, infants with a syndrome had greater proportions of bilateral than unilateral CHL. Risk factors of craniofacial abnormality, prolonged ventilation, or syndrome had greater proportions of mild to moderate CHL than moderate or greater. On average, infants were diagnosed with a CHL at 37.29 weeks of age. These findings highlight the relationship between clinical/demographic characteristics and occasions of service to diagnose CHL in children, including the CHL profile. An understanding of this relationship may help clinicians to better plan, assess and manage infants diagnosed with a CHL through UNHS.

Comparison of Active Bone Conduction Hearing Implant Systems in Unilateral and Bilateral Conductive or Mixed Hearing Loss.

To assess and compare binaural benefits and subjective satisfaction of active bone conduction implant (BCI) in patients with bilateral conductive or mixed hearing loss fitted with bilateral BCI and patients with monaural conductive hearing loss fitted with monaural BCI. ITA Matrix test was performed both on patients affected by bilateral conductive or mixed hearing loss fitted with monaural bone conduction hearing implant (Bonebridge, Med-El) before and after implantation of contralateral bone conduction hearing implant and on patients with monaural conductive or mixed hearing loss before and after implantation of monaural BCI. The Abbreviated Profile of Hearing Aid Benefit (APHAB) questionnaire was administered to both groups of subjects and the results were compared with each other. Patients of group 1 reported a difference of 4.66 dB in the summation setting compared to 0.79 dB of group 2 (p < 0.05). In the squelch setting, group 1 showed a difference of 2.42 dB compared to 1.53 dB of group 2 (p = 0.85). In the head shadow setting, patients of group 1 reported a difference of 7.5 dB, compared to 4.61 dB of group 2 (p = 0.34). As for the APHAB questionnaire, group 1 reported a mean global score difference of 11.10% while group 2 showed a difference of -4.00%. Bilateral BCI in patients affected by bilateral conductive or mixed hearing loss might show more advantages in terms of sound localisation, speech perception in noise and subjective satisfaction if compared to unilateral BCI fitting in patients affected by unilateral conductive hearing impairment. This may be explained by the different individual transcranial attenuation of each subject, which might lead to different outcomes in terms of binaural hearing achievement. On the other hand, patients with unilateral conductive or mixed hearing loss fitted with monaural BCI achieved good results in terms of binaural hearing and for this reason, there is no absolute contraindication to implantation in those patients.

The Effects of Utilizing Cartilage Conduction Hearing Aids among Patients with Conductive Hearing Loss

The cartilage-conduction hearing aid (CC-HA) is a new hearing device that is suitable for use in patients with conductive hearing loss. It has been 5 years since the introduction of the CC-HA. Although the number of users has increased, the CC-HA is not yet widely known. This study examines the effects of CC-HA on patients with conductive hearing loss and investigates factors that affect the willingness to use the device by comparing purchasers and non-purchasers of CC-HA in patients with unilateral conductive hearing loss. Eight patients had bilateral conductive hearing loss, and 35 had unilateral conductive hearing loss. Each patient underwent sound field tests and speech audiometry, and the effects of the CC-HA were compared with those of conventional bone conduction hearing aids (BC-HA). In patients with bilateral conductive hearing loss, the CC-HA was non-inferior to BC-HA. The CC-HA improved the hearing thresholds and speech recognition in patients with unilateral conductive hearing loss. Moreover, in patients with unilateral conductive hearing loss, experiencing the effect of wearing the CC-HA under conditions such as putting noise in the better ear could affect patients’ willingness to use the CC-HA.

Persistence and generalization of adaptive changes in auditory localization behavior following unilateral conductive hearing loss.

Sound localization relies on the neural processing of binaural and monaural spatial cues generated by the physical properties of the head and body. Hearing loss in one ear compromises binaural computations, impairing the ability to localize sounds in the horizontal plane. With appropriate training, adult individuals can adapt to this binaural imbalance and largely recover their localization accuracy. However, it remains unclear how long this learning is retained or whether it generalizes to other stimuli. We trained ferrets to localize broadband noise bursts in quiet conditions and measured their initial head orienting responses and approach-to-target behavior. To evaluate the persistence of auditory spatial learning, we tested the sound localization performance of the animals over repeated periods of monaural earplugging that were interleaved with short or long periods of normal binaural hearing. To explore learning generalization to other stimulus types, we measured the localization accuracy before and after adaptation using different bandwidth stimuli presented against constant or amplitude-modulated background noise. Retention of learning resulted in a smaller initial deficit when the same ear was occluded on subsequent occasions. Each time, the animals' performance recovered with training to near pre-plug levels of localization accuracy. By contrast, switching the earplug to the contralateral ear resulted in less adaptation, indicating that the capacity to learn a new strategy for localizing sound is more limited if the animals have previously adapted to conductive hearing loss in the opposite ear. Moreover, the degree of adaptation to the training stimulus for individual animals was significantly correlated with the extent to which learning extended to untrained octave band target sounds presented in silence and to broadband targets presented in background noise, suggesting that adaptation and generalization go hand in hand. Together, these findings provide further evidence for plasticity in the weighting of monaural and binaural cues during adaptation to unilateral conductive hearing loss, and show that the training-dependent recovery in spatial hearing can generalize to more naturalistic listening conditions, so long as the target sounds provide sufficient spatial information.

Salivary Gland Choristoma of the Middle Ear: Case Report

Choristoma, a salivary gland tumor, may localize at unforeseen locations. Since 1961 when it was first described, roughly 50 cases of choristoma have been accounted for, including 30 cases among pediatric–adolescents. The patient in this current study is a girl of 14 years of age. She was admitted to a tertiary otolaryngology polyclinic with right-sided hearing problems and aural fullness complaint. Her average airway hearing level measured using the pure tone audiometry hearing test was 70 dB, whereas the bone conduction pure tone average was 6 dB. A high-resolution computerized tomography of the temporal bone demonstrated a mass behind the intact tympanic membrane. The tumor was excised entirely over the facial nerves tympanic part of the facial nerve with careful dissection. Histopathological examination revealed the tumor to be a salivary gland choristoma. In this article, we present the case of a 14-year-old girl with unilateral conductive hearing loss caused by salivary gland choristoma.

Audiometric and Surgical Outcomes of a Novel Bone-Conduction Hearing Aid.

To report the audiometric and surgical outcomes of a series of patients having undergone implantation of a novel transcutaneous bone conduction implant (t-BCI). Retrospective case series. Single academic tertiary referral center. Adults (≥18 yr) implanted between December 1, 2019, and August 1, 2021, with audiometric data available before and after device implantation and a minimum of 4 weeks follow-up. Surgical t-BCI. Change in aided pure tone average (PTA) after implantation. Secondary outcomes include average operative time, and adverse events. Twenty-three patients underwent implantation of the t-BCI via either a conventional or minimally invasive surgical approach. The most common indication for implantation was unilateral conductive hearing loss with a history of chronic otitis media. The mean operative time was 59 minutes. The mean preimplantation unaided air conduction PTA was 65 dB, and mean postimplantation was 27.2 dB. The mean change in PTA was 37.8 dB, which was significant ( p < 0.0001). There were 30.4% of the patients that suffered from adverse events, the most common of which were pain (8.7%) and device-related complications (13%). One major adverse event occurred, involving magnet displacement that impaired device activation and required reoperation for replacement. Forming the largest series of patients implanted with this t-BCI in the published literature, our data demonstrate that implantation of the device is feasible via either a traditional or minimally invasive surgical approach, with good audiometric benefit and a favorable safety profile.

Stapedotomy Versus Hearing Aids in the Management of Conductive Hearing Loss Caused by Otosclerosis: A Prospective Comparative Study.

To compare the outcomes of patients with unilateral otosclerosis treated consecutively by a hearing aid then stapedotomy. Monocentric, nonrandomized, prospective, longitudinal, cohort study. Tertiary university hospital. Adult patients with a unilateral conductive hearing loss of at least 30 dB caused by otosclerosis. Consecutive treatment by an external hearing aid followed by stapedotomy. Differences between hearing aids and stapedotomy in quality of life, pure-tone audiometry, binaural hearing, tinnitus severity, and patient satisfaction. Twenty-two patients were included, of which 20 (91%) underwent stapedotomy. Stapedotomy demonstrated increased quality of life according to Glasgow Health Status Inventory scores versus hearing aids (+10.4 ± 9.4 [p = 0.0001]). Stapedotomy versus hearing aids showed improved pure-tone averages (-11.1 ± 11.0 dB [p = 0.002]) and air-bone gaps (-11.8 ± 10.7 dB [p = 0.0006]). Stapedotomy was superior to hearing aids for speech-in-noise recognition in the reverse dichotic condition (-8.4 ± 26.9 dB [p = 0.004]) and showed improved sound localization accuracy in root mean square error (-14.5 ± 24.5 degrees [p = 0.02]). Stapedotomy, but not hearing aids, showed improved patient self-evaluated tinnitus after baseline adjustment according to the Tinnitus Handicap Inventory (-8.0 ± 13.4 [p = 0.02]) and visual analog scale for tinnitus intensity (-28.7 ± 34.1 [p = 0.006]). Overall, patients were more satisfied with surgery versus hearing aids. Stapedotomy remains more effective compared with hearing aids with greater improvements in quality of life, patient satisfaction, hearing outcomes, and self-evaluated tinnitus.

The Effect of Hearing Aids on Sound Localization in Mild Unilateral Conductive Hearing Loss.

Binaural hearing is of utmost importance for communicating in noisy surroundings and localizing the direction of sound. Unilateral hearing loss (UHL) affects the quality of life in both childhood and adulthood, speech development, and academic achievements. Sound amplification using air-conducting hearing aids (HAs) is a common option for hearing rehabilitation of UHL. The processing time of digital HAs can significantly delay the acoustic stimulation in 3 to 10 milliseconds, which is far longer than the maximal natural interaural time difference (ITD) of 750 microseconds. This can further impair spatial localization in these patients. We sought to assess whether HA effects on ITD and interaural level difference (ILD) impair localization among subjects with unilateral conductive hearing loss (UCHL). "Normal"-hearing participants underwent localization testing in different free field settings. Ten volunteers with "normal"-hearing thresholds participated. Repeated assessments were compared between "normal" (binaural) hearing, UCHL induced by insertion of an inactivated HA to the ear canal (conductive HL), and amplification with a HA. In UCHL mode, with HA switched-off, localization was significantly impaired compared to "normal" hearing (NH; η2 = 0.151). Localization error was more pronounced when sound was presented from the front and from the side of the occluded ear. When switched-on, amplification with HAs significantly improved localization for all participants compared to UCHL. Better localization with HAs was seen in high frequencies compared to low frequencies (η2 = 0.08, 0.03). Even with HAs, localization did not reach that of NH (η2 = 0.034). Mild UCHL caused localization to deteriorate. HAs significantly improved sound localization, albeit the delay caused by the device processing time. Most of the improvements were seen in high-frequency sounds, representing a beneficial effect of amplification on ILD. Our results have potential clinical value in situations of mild CHL, for instance, otitis media with effusion.

PREDICTING THE SUBJECTIVE HEARING OUTCOME IN TYPE I TYMPANOPLASTY USING BELFAST 15/30DB RULE OF THUMB.

OBJECTIVE: Both Otologists and patients mutually hope for an improvement in hearing and a functional benet from an ear surgery to correct unilateral conductive hearing loss that has been reported as the closure of air-bone gap or reduction in air conduction thresholds. While these provide a measure of technical success of the operation, they may not always translate into real life benet for the patient. This is because listening is a binaural task and benet to the patient is determined by numerous factors, of paramount importance is hearing in the non-operated ear. With the aim, to estimate patient benet in terms of subjective hearing gain after type I tympanoplasty, we reviewed the Belfast 15/30 dB rule of thumb. METHOD: A 100 cases of chronic otitis media with inactive mucosal disease having conductive hearing loss, who had undergone type I tympanoplasty were included. Hearing was assessed using pure tone audiogram with average of, .5, 1, 2 &amp; 4Hz and a detailed questionnaire regarding the subjective perception of hearing was obtained pre and 6 month post-operatively which was correlated with Belfast 15/30 dB rule of thumb. RESULT: The predictive value as per pure tone audiometry with Belfast 15/30 dB rule of thumb is 89% with a conclusion that the objective hearing improvement (88.1%) does not necessarily transform into patients' perception of hearing improvement (78.4%) CONCLUSION: Hearing is a binaural function and this should always be kept in mind while operating on unilateral/ asymmetric hearing loss patients as mere closure of air-bone gap or reduction in air conduction threshold might not conclude patients' perception of hearing gain. Belfast 15/30 dB rule of thumb has proved to be a valuable tool in predicting the subjective improvement of hearing

Congenital cholesteatoma: Clinical features and surgical outcomes

ObjectivesA typical presentation of congenital cholesteatoma (CC) is asymmetric conductive hearing loss (CHL). As CHL is usually associated with middle ear effusion, diagnosis of CC is frequently delayed. This study aimed to describe the clinical characteristics, treatment and outcomes of children with CC. MethodsThe medical files of children diagnosed with CC at a large tertiary pediatric medical center during 2000–2019 were reviewed. The primary outcome measures were: presenting symptoms, surgical findings, stage of disease, recurrence rate and hearing outcome. Imaging findings and the size of mastoid air cells were assessed in CT scans. ResultsThirty-nine children were diagnosed with CC. The presenting symptom was unilateral CHL in 85%, with an average speech reception threshold of 41.5 ± 13.7 dB in the affected ear. The mean time from first symptoms to diagnosis was 1.3 years. The surgical approach was exploratory tympanotomy in 25% and canal wall up mastoidectomy in 69%. Seventy percent of the children presented with Potsic stage III-IV. The mean postoperative speech reception threshold was 26.4 ± 12.2 dB (P = 0.002). Recurrence of cholesteatoma occurred in 38% of the patients, mostly in stage III-IV. Mastoid air cell size was significantly smaller on the affected than the unaffected side. ConclusionsIn children with persistent unilateral or asymmetric conductive hearing loss, CC should be suspected. Late diagnosis of CC is associated with a high recurrence rate. This highlights the need to promote awareness to the disease among primary physicians in the community health care system.

Are children with unilateral hearing loss more tired?

ObjectiveTo determine whether children with unilateral sensorineural hearing loss (USNHL) and unilateral conductive hearing loss (UCHL) have higher levels of fatigue than literature reported normal hearing (LRNH) children. MethodsThis was a cross-sectional survey utilizing the PedsQL™ Multidimensional Fatigue Scale administered to children with unilateral hearing loss (UHL) and their parents at two tertiary care academic medical centers and a nationwide microtia/atresia conference. The PedsQL™ Multidimensional Fatigue Scale was used to compare child and parental proxy reports of fatigue among USNHL, UCHL, and LRNH children. ANOVA and post-hoc Tukey Honest Significant Difference testing were used for statistical analysis. ResultsOf 69 children included in the study, 42 had UCHL (61%) and 27 (39%) had USNHL. Children with USNHL reported more total fatigue (mean 69.1, SD 19.3) than LRNH children (mean 80.5, SD 13.3; difference −11.4; 95% CI: −19.98 to −2.84) and children with UCHL (mean 78.0, SD 14.5; difference −8.95; 95% CI: −17.86 to 0.04). Children with UCHL reported similar levels of fatigue compared to LRNH children (difference −2.5; 95% CI: −9.95 to 5.03).Parents of children with USNHL reported greater levels of fatigue (mean 67.6, SD 22.6) in their children than parents of LRNH children (mean 89.6, SD 11.4; difference −22.0; 95% CI: −29.8 to −14.3) and parents of children with UCHL (mean 76.2, SD 17.3; difference −8.6; 95% CI: −17.5 to 0.21). Parents of children with UCHL also report higher levels of fatigue than parents of LRNH children (difference −13.4; 95% CI: −19.98 to −6.84). ConclusionsChildren with USNHL reported greater levels of fatigue than LRNH children and children with UCHL. Results implicate cognitive load as an important consideration in children with hearing loss. The measurement of fatigue may be a useful indicator to determine the benefit of intervention (e.g., amplification) for these children.

Comparing the diagnostic accuracy of audiometric Weber test and tuning fork Weber test in patients with conductive hearing loss.

ObjectivesWeber test is typically conducted using tuning forks, but an audiometer can also be used for a similar purpose. Compared to the tuning fork Weber (TFW) test, performing the audiometric Weber (AW) test offers many advantages. Nevertheless, AW and TFW tests' performance compared to pure‐tone audiometry (PTA) has yet to be studied. The present study aimed to determine the accuracy and agreement between the AW and TFW tests compared to PTA.MethodsIn this observational cross‐sectional study, 74 participants (aged 12‐67 years) with unilateral conductive hearing loss (CHL) or bilateral asymmetrical CHL were enrolled. The TFW test was performed according to the established protocol at 256 and 512 Hz. For the AW test, the bone vibrator was placed in the middle of the forehead, where 250 and 500 Hz frequencies were tested. TF and AW test results were then compared with the expected lateralization from the respective PTA results.ResultsAt 256 Hz (or 250 Hz), the overall accuracy values of TFW and AW tests were 81.1% and 86.5%, respectively. At 512 Hz (or 500 Hz), the overall accuracy results of TFW and AW tests were 85.1% and 82.4%, respectively. In addition, the kappa statistics revealed substantial agreements between the two tests and PTA (k = .63‐.72).ConclusionBoth AW and TFW tests are reasonably accurate in assessing patients with CHL. It is recommended for audiologists to perform the simple AW test to verify incomplete or questionable audiograms that are commonly encountered in clinical practice.Level of evidenceLevel 3b.

Unilateral Conductive Hearing Loss Disrupts the Developmental Refinement of Binaural Processing in the Rat Primary Auditory Cortex.

Binaural hearing is critically important for the perception of sound spatial locations. The primary auditory cortex (AI) has been demonstrated to be necessary for sound localization. However, after hearing onset, how the processing of binaural cues by AI neurons develops, and how the binaural processing of AI neurons is affected by reversible unilateral conductive hearing loss (RUCHL), are not fully elucidated. Here, we determined the binaural processing of AI neurons in four groups of rats: postnatal day (P) 14–18 rats, P19–30 rats, P57–70 adult rats, and RUCHL rats (P57–70) with RUCHL during P14–30. We recorded the responses of AI neurons to both monaural and binaural stimuli with variations in interaural level differences (ILDs) and average binaural levels. We found that the monaural response types, the binaural interaction types, and the distributions of the best ILDs of AI neurons in P14–18 rats are already adult-like. However, after hearing onset, there exist developmental refinements in the binaural processing of AI neurons, which are exhibited by the increase in the degree of binaural interaction, and the increase in the sensitivity and selectivity to ILDs. RUCHL during early hearing development affects monaural response types, decreases the degree of binaural interactions, and decreases both the selectivity and sensitivity to ILDs of AI neurons in adulthood. These new evidences help us to understand the refinements and plasticity in the binaural processing of AI neurons during hearing development, and might enhance our understanding in the neuronal mechanism of developmental changes in auditory spatial perception.

Temporary Unilateral Hearing Loss Impairs Spatial Auditory Information Processing in Neurons in the Central Auditory System.

Temporary conductive hearing loss (CHL) can lead to hearing impairments that persist beyond resolution of the CHL. In particular, unilateral CHL leads to deficits in auditory skills that rely on binaural input (e.g., spatial hearing). Here, we asked whether single neurons in the auditory midbrain, which integrate acoustic inputs from the two ears, are altered by a temporary CHL. We introduced 6 weeks of unilateral CHL to young adult chinchillas via foam earplug. Following CHL removal and restoration of peripheral input, single-unit recordings from inferior colliculus (ICC) neurons revealed the CHL decreased the efficacy of inhibitory input to the ICC contralateral to the earplug and increased inhibitory input ipsilateral to the earplug, effectively creating a higher proportion of monaural responsive neurons than binaural. Moreover, this resulted in a ∼10 dB shift in the coding of a binaural sound location cue (interaural-level difference, ILD) in ICC neurons relative to controls. The direction of the shift was consistent with a compensation of the altered ILDs due to the CHL. ICC neuron responses carried ∼37% less information about ILDs after CHL than control neurons. Cochlear peripheral-evoked responses confirmed that the CHL did not induce damage to the auditory periphery. We find that a temporary CHL altered auditory midbrain neurons by shifting binaural responses to ILD acoustic cues, suggesting a compensatory form of plasticity occurring by at least the level of the auditory midbrain, the ICC.

Postoperative Benefit of Bone Anchored Hearing Systems: Behavioral Performance and Self-Reported Outcomes.

Introduction Bone anchored hearing solutions are a well-known option for patients with a conductive, mixed conductive-sensorineural hearing loss and those with single-sided deafness. Objective The aim of the present study was to evaluate the Ponto bone-anchored hearing system in terms of behavioral performance and self-reported outcomes, by comparing unaided and aided performance (softband and abutment), as well as aided performance with the sound processor on softband (preoperatively) versus abutment (postoperatively). Methods Fourteen adult bone-anchored candidates, with either a bilateral ( n = 12) or unilateral ( n = 2) conductive or mixed hearing loss, participated in the present study. Sound-field hearing thresholds were evaluated unaided and aided (softband and abutment). A speech-in-noise test was also performed unaided and aided for two spatial configurations (S0N90; implanted side; S0N90; nonimplanted side). The Glasgow Health Status Inventory and the Speech, Spatial and Quality of sound questionnaires were administered pre- and postsurgery to compare quality of life and perceived unaided and aided performance. Skin reaction (Holgers scores) was evaluated at 15 days, 6 weeks, and 10 weeks after surgery. Results Significant improvements postoperatively relative to unaided were obtained for sound-field thresholds at all tested frequencies. Additionally, sound-field thresholds were significantly improved with the sound processor on abutment relative to the softband at frequencies > 1 kHz. Improved performance postoperatively relative to unaided was also obtained in the speech-in-noise test and in self-reported outcomes. Conclusions Improvements in behavioral performance and self-reported outcomes were obtained with the sound processor mounted on abutment.

Poor speech recognition, sound localization and reorganization of brain activity in children with unilateral microtia-atresia

Microtia-atresia is a congenital malformation of the external ear, often affecting one side and being associated with severe-to-profound unilateral conductive hearing loss (UCHL). Although the impact of unilateral hearing loss (UHL) on speech recognition, sound localization and brain plasticity has been intensively investigated, less is known about the subjects with unilateral microtia-atresia (UMA). Considering these UMA subjects have hearing loss from birth, we hypothesize it has a great effect on brain organization. A questionnaire on speech recognition and spatial listening ability was administered to 40 subjects with UMA and 40 age- and sex-matched controls. UMA subjects showed poorer speech recognition in laboratory and poorer spatial listening ability. However, cognitive scores determined by the Montreal Cognitive Assessment (MoCA) and Wechsler Intelligence Scale for Children (WISC-IV) did not differ significantly in these two groups. The impact of hearing loss in UMA on brain functional organization was examined by comparing resting-state fMRIs (rs-fMRI) in 27 subjects with right-sided UMA and 27 matched controls. UMA subjects had increased nodal betweenness in visual networks and DMN but decreases in auditory and attention networks. These results indicate that UCHL in UMA causes significant abnormalities in brain organization. The impact of UCHL on cognition should be further examined with a battery of tests that are more challenging and better focused on the cognitive networks identified.

Instant auditory benefit of an adhesive BCHD on children with bilateral congenital microtia

Bilateral congenital microtia commonly leads to mild-to-severe conductive hearing loss (CHL), which significantly affects daily communication, causing developmental retardation of speech, poor learning achievement and mental diseases [1]. Bone conduction hearing devices (BCHDs), wearable or implanted, are widely used to restore their hearing ability [2]. Most wearable BCHDs are attached to the skin (mastoid or forehead) with a softband, steel-spring headband, or other fixation types, causing a static pressure [3]. This pressure leads to discomfort, skin reactions and pains for long-term use. The pressure problem also exists in implantable bone conduction systems via magnets (such as BAHA attract and Sophono) [4]. ADHEAR is a pressure-free wearable BCHD, with an adhesive adapter to ensure fixation. The auditory benefit of ADHEAR has already been estimated for bilateral or unilateral CHL in both adults [5] and children [6]. However, the data for children with congenital microtia is still needed.