Lipochoristoma: a rare cause of unilateral hearing loss.

We present our single-centre experience of two cases of lipochoristoma, a rare lesion causing unilateral hearing loss. Differential diagnoses include the more common vestibular schwannoma, haemangioma and meningioma. Diagnosis was confirmed with fat suppression sequences on MRI. Management of both patients was with serial imaging, under the guidance of neuro-otology multidisciplinary team, due to the slow and typically non-aggressive progression of this lesion.

Cochlear Implantation in Single-Sided Deafness and Asymmetric Hearing Loss: 12 Months Follow-up Results of a European Multicenter Evaluation.

People with single-sided deafness (SSD) or asymmetric hearing loss (AHL) have particular difficulty understanding speech in noisy listening situations and in sound localization. The objective of this multicenter study is to evaluate the effect of a cochlear implant (CI) in adults with single-sided deafness (SSD) or asymmetric hearing loss (AHL), particularly regarding sound localization and speech intelligibility with additional interest in electric-acoustic pitch matching. A prospective longitudinal study at 7 European tertiary referral centers was conducted including 19 SSD and 16 AHL subjects undergoing cochlear implantation. Sound localization accuracy was investigated in terms of root mean square error and signed bias before and after implantation. Speech recognition in quiet and speech reception thresholds in noise for several spatial configurations were assessed preoperatively and at several post-activation time points. Pitch perception with CI was tracked using pitch matching. Data up to 12 months post activation were collected. In both SSD and AHL subjects, CI significantly improved sound localization for sound sources on the implant side, and thus overall sound localization. Speech recognition in quiet with the implant ear improved significantly. In noise, a significant head shadow effect was found for SSD subjects only. However, the evaluation of AHL subjects was limited by the small sample size. No uniform development of pitch perception with the implant ear was observed. The benefits shown in this study confirm and expand the existing body of evidence for the effectiveness of CI in SSD and AHL. Particularly, improved localization was shown to result from increased localization accuracy on the implant side.

Middle-Ear Salivary Gland Choristoma with Congenital, Single-Sided Hearing Loss.

Middle-ear salivary gland choristoma (SGCh) is a rare, benign tumor that causes conductive hearing loss owing to middle-ear morphological abnormalities. Early diagnosis is challenging, and surgical resection is indispensable for a definitive diagnosis. We report the case of a 3-year-old boy diagnosed with middle-ear SGCh during the follow-up period for left-sided hearing loss discovered at newborn hearing screening (NHS). Long-term follow-up after the NHS result, subsequent computed tomography/magnetic resonance imaging, and surgical resection led to its relatively early diagnosis and treatment.

Biomarkers of auditory cortical plasticity and development of binaural pathways in children with unilateral hearing loss using a hearing aid.

Congenital or early-onset unilateral hearing loss (UHL) can disrupt the normal development of the auditory system. In extreme cases of UHL (i.e., single sided deafness), consistent cochlear implant use during sensitive periods resulted in cortical reorganization that partially reversed the detrimental effects of unilateral sensory deprivation. There is a gap in knowledge, however, regarding cortical plasticity i.e. the brain's capacity to adapt, reorganize, and develop binaural pathways in milder degrees of UHL rehabilitated by a hearing aid (HA). The current study was set to investigate early-stage cortical processing and electrophysiological manifestations of binaural processing by means of cortical auditory evoked potentials (CAEPs) to speech sounds, in children with moderate to severe-to-profound UHL using a HA. Fourteen children with UHL (CHwUHL), 6-14 years old consistently using a HA for 3.5 (±2.3) years participated in the study. CAEPs were elicited to the speech sounds /m/, /g/, and /t/ in three listening conditions: monaural [Normal hearing (NH), HA], and bilateral [BI (NH + HA)]. Results indicated age-appropriate CAEP morphology in the NH and BI listening conditions in all children. In the HA listening condition: (1) CAEPs showed similar morphology to that found in the NH listening condition, however, the mature morphology observed in older children in the NH listening condition was not evident; (2) P1 was elicited in all but two children with severe-to-profound hearing loss, to at least one speech stimuli, indicating effective audibility; (3) A significant mismatch in timing and synchrony between the NH and HA ear was found; (4) P1 was sensitive to the acoustic features of the eliciting stimulus and to the amplification characteristics of the HA. Finally, a cortical binaural interaction component (BIC) was derived in most children. In conclusion, the current study provides first-time evidence for cortical plasticity and partial reversal of the detrimental effects of moderate to severe-to-profound UHL rehabilitated by a HA. The derivation of a cortical biomarker of binaural processing implies that functional binaural pathways can develop when sufficient auditory input is provided to the affected ear. CAEPs may thus serve as a clinical tool for assessing, monitoring, and managing CHwUHL using a HA.

Localization and Speech-in-Noise Performance in a Virtual Reality Test Environment: A Pilot Study of Adults With Single-Sided Deafness Using a Cochlear Implant.

PURPOSE: The purpose of this exploratory study was to (a) construct a virtual reality (VR) test environment to measure speech recognition in noise (SIN) and localization, and (b) use the VR test environment to establish degree of binaural hearing benefit among a small number of adults with single-sided deafness (SSD) using a cochlear implant (CI). METHOD: This pilot study included five adults implanted for SSD. The test environment was composed of an eight-speaker array that delivered restaurant noise and Institute of Electrical and Electronics Engineers sentences. VR head-mounted display goggles delivered a video recording of a busy restaurant. Participants completed SIN and localization in two conditions: (a) normal-hearing ear and a CI on the contralateral SSD side (CI-ON) and (b) normal-hearing ear and unaided on the contralateral SSD side (CI-OFF). RESULTS: Overall, CI benefits for SIN and localization within the VR test environment were improved for some participants, although not all. CI benefit for SIN and localization was dependent on speaker location. CONCLUSIONS: VR test environments present new opportunities for studying SIN and localization abilities in participants with CIs. This pilot study shows that, within a VR test environment, degree of CI benefit among SSD participants for SIN and localization varies across speaker location and across participants.

Cochlear implantation in children with single-sided deafness under the age of 5 years: a review of current literature.

PURPOSE OF REVIEW: Here we explore the current literature on cochlear implantation of pediatric patients under the age of 5 years with single-sided deafness (SSD). RECENT FINDINGS: Single-sided deafness has been noted to cause developmental delays in speech, language, and cognition because of loss of binaural hearing. Currently, cochlear implantation is the only intervention capable of restoring binaural hearing for pediatric patients with SSD. Young children have been shown to have the greatest neuroplasticity of the auditory cortex before 4 years of age. Currently, only children over the age of 5 years are approved by the United States Food and Drug Administration (FDA) to undergo cochlear implantation for SSD. Cochlear implantation for SSD in patients under the age of 5 years has been performed on a limited basis and has been shown to have excellent results. SUMMARY: Cochlear implantation is a well tolerated and effective treatment for pediatric patients under the age of 5 years with SSD. Receiving cochlear implantation under the age of 5 years is critical for child development as neuroplasticity decreases after this age.

Sound Localization in Active Transcutaneous Bone Conduction Implant Users with Single-Sided Deafness.

OBJECTIVE: Evaluate sound localization accuracy of subjects with single-sided deafness (SSD) with active transcutaneous bone conduction implants (atBCIs). STUDY DESIGN: Prospective case-control study. SETTING: Tertiary referral center. PATIENTS: Ten SSD patients (with ATBCIS) and 10 controls. INTERVENTIONS: Localization was assessed in a semianechoic chamber using a 24-speaker array. Stimuli included broadband noise (BBN) and narrowband noise (NBN). Perceived stimulus angle was recorded and compared with presented location. Statistical analyses were performed using ANOVA and Wilcoxon rank sum tests. MAIN OUTCOME MEASURES: The primary outcome measures were as follows: 1) mean angular error (MAE) error (°) and regression slope and 2) subjective benefit assessment (Speech Spatial Qualities questionnaire). RESULTS: Subjects with SSD demonstrated worse localization by MAE and regression slope compared with controls for both broadband noise (p < 0.0001) and narrowband noise at 500 Hz and 1000 kHz (p < 0.0001). There was no statistically significant difference (p = 0.1090) in slope between all groups at 4000 Hz. There was no significant difference in slope or MAE aided compared with unaided. Localization ability varied widely within the SSD cohort, with some individuals showing some ability in the unaided condition, best at 4000 Hz. Although SSQ confirmed particular difficulty in the spatial hearing domain, all domains improved with device use. CONCLUSIONS: Localization ability for individuals with SSD falls into a somewhat bimodal distribution. Some have fair localization, particularly at high frequencies, that is preserved but not improved with the atBCI. Others have minimal to no localization ability at any frequency, with no apparent device benefit.

P1-N1-P2 Cortical Auditory Evoked Potentials in Chronic Unilateral Acquired Conductive Hearing Loss in Adults.

BACKGROUND:  Chronic unilateral hearing loss causes imbalanced auditory input to the brain that triggers cortical reorganization. The effect of sensorineural hearing loss on the central auditory system (CAS) has been thoroughly studied, while there is a paucity of research on the effect of conductive hearing loss (CHL). The aim of this study was to assess the P1-N1-P2 cortical auditory evoked response potential (CAEP) in adult individuals with chronic acquired unilateral CHL. METHODS:  This study included 108 participants of both genders: 54 patients with unilateral chronic CHL who were compared to well-matched 54 controls. All were subjected to history-taking, otologic examination, basic audiological evaluation, and bone conduction N1-P2 CAEP. RESULTS:  The affected ears of the cases showed highly statistically significant shorter CAEPs N1, P2, N1-P2 latencies but not P1, and showed highly statistically significant larger N1, P2, N1P2, amplitude than the control group. Latencies decreased and amplitudes increased as the degree of CHL increased, but were not affected by patients' age, side, or duration of the CHL. Cases with tinnitus had statistically significant and worse results than those without tinnitus. CONCLUSION:  Unilateral chronic CHL might enhance neurocortical plasticity, with greater changes occurring at greater degrees of the CHL.

Do Otologists and Other Otolaryngologists Manage Single-Sided Deafness Differently?

BACKGROUND:  The aim of this study was to survey the knowledge and treatment management practices for single-sided deafness (SSD) among different subspecialties of otolaryngology. METHODS:  A questionnaire was sent via Google Sheets to members of the Turkish and Egyptian Otorhinolaryngology Societies between December 2021 and February 2022. For the statistical analysis, the respondents were divided into 3 groups as otologists, non-otologists, and residents at the department of otolaryngology-head and neck department. RESULTS:  There were no statistically significant differences between otologists and non-otologists in radiological imaging (child P = .469, adult P = .140) and preferred treatment method (child P = .546, adult P = .106). However, otolaryngologists showed significant differences in radiological evaluation (P <.001), vestibular evaluation (P = .000), and frequency of treatment options recommended for pediatric and adult SSD patients (P = .000). CONCLUSION:  There were no significant differences in SSD diagnosis, treatment, and rehabilitation between otologists and non-otologists. However, when comparing pediatric and adult patients, there was a difference in the treatment management of SSD patients.

Speech Recognition and Subjective Hearing Abilities for Electric-Acoustic Stimulation Users With Unilateral Hearing Loss.

OBJECTIVE: Some cochlear implant (CI) recipients with unilateral hearing loss (UHL) have functional acoustic hearing in the implanted ear, warranting the fitting of an ipsilateral electric-acoustic stimulation (EAS) device. The present study assessed speech recognition and subjective hearing abilities over time for EAS users with UHL. STUDY DESIGN: Prospective, repeated-measures. SETTING: Tertiary referral center. PATIENTS: Adult CI recipients with normal-to-moderate low-frequency acoustic thresholds in the implanted ear and a contralateral pure-tone average (0.5, 1, and 2 kHz) ≤25 dB HL. MAIN OUTCOME MEASURES: Participants were evaluated preoperatively and at 1, 3, and 6 months post-activation. Speech recognition for the affected ear was evaluated with CNC words in quiet. Masked speech recognition in the bilateral condition was evaluated with AzBio sentences in a 10-talker masker (0 dB SNR) for three spatial configurations: target from the front and masker either colocated with the target or presented 90 degrees toward the affected or contralateral ear. Responses to the Speech, Spatial, and Qualities of Hearing Scale subscales were used to assess subjective hearing abilities. RESULTS: Participants experienced significant improvements in CNC scores ( F(3,13) = 14.90, p < 0.001), and masked speech recognition in the colocated ( F(3,11) = 3.79, p = 0.043) and masker toward the contralateral ear ( F(3,11) = 4.75, p = 0.023) configurations. They also reported significantly better abilities on the Speech Hearing ( F(3,13) = 5.19, p = 0.014) and Spatial Hearing ( F(3,13) = 10.22, p = 0.001) subscales. CONCLUSIONS: Adults with UHL and functional acoustic hearing in the implanted ear experience significant improvements in speech recognition and subjective hearing abilities within the initial months of EAS use as compared with preoperative performance and perceptions.

Duration of cochlear implant use in children with prelingual single-sided deafness is a predictor of word perception in the CI ear.

As part of a longitudinal study regarding the benefit of early cochlear implantation for children with single-sided deafness, the current work explored the children's daily device use, potential barriers to full-time device use, and the children's ability to understand speech with the cochlear implant (CI). Data were collected from 20 children with prelingual SSD who received a CI before the age of 2.5 years, from the initial activation of the sound processor until the children were 4.8 to 11.0 years old. Daily device use was extracted from the CI's data logging, while word perception in quiet was assessed using direct audio input to the children's sound processor. The children's caregivers completed a questionnaire about habits, motivations, and barriers to device use. The children with SSD and a CI used their device on average 8.3 h per day, corresponding to 63 % of their time spent awake. All children except one could understand speech through the CI, with an average score of 59 % on a closed-set test and 73 % on an open-set test. More device use was associated with higher speech perception scores. Parents were happy with their decision to pursue a CI for their child. Certain habits, like taking off the sound processor during illness, were associated with lower device use. Providing timely counselling to the children's parents, focused on SSD-specific challenges, may be helpful to improve daily device use in these children.

Adaptive Strategies of Single-Sided Deaf Cochlear-Implant Users Revealed Through Resting State Activity: an Auditory PET Brain Imaging Study.

Brain plasticity refers to the brain's ability to reorganize its structure or function in response to experiences, learning, and environmental influences. This phenomenon is particularly significant in individuals with deafness, as the brain adapts to compensate for the lack of auditory stimulation. The aim of this study is to investigate whether cochlear implantation can restore a normal pattern of brain activation following auditory stimulation in cases of asymmetric hearing loss. We used a PET-scan technique to assess brain activity after cochlear implantation, specifically during an auditory voice/non-voice discrimination task. The results indicated a nearly normal pattern of brain activity during the auditory discrimination task, except for increased activation in areas related to attentional processes compared to controls. Additionally, brain activity at rest showed significant changes in implanted participants, including cross modal visuo-auditory processing. Therefore, cochlear implants can restore the brain's activation pattern through long-term adaptive adjustments in intrinsic brain activity.

Auditory Localization Performance in Cochlear Implant Recipients With Single-Sided Deafness: The Challenges and Limitations of Current Outcome Metrics.

HYPOTHESIS: Acoustic localization accuracy metrics currently employed in clinical literature both overestimate and underestimate performance benefit of cochlear implantation (CI) for single-sided deafness (SSD). BACKGROUND: Although localization in SSD with CI has been investigated, performance characterization has relied heavily on average error. Although attractively concise, this measure may misrepresent performance. Here, we characterize frequency-specific localization on a granular level in subjects with CI for SSD as a critical analysis of localization outcome metrics. METHODS: Eight CI recipients with SSD were recruited. Stimuli of broadband (BBN) and narrowband noise (NBN) at low (500 Hz), mid (1000 Hz), and high (4000 Hz) frequencies were presented in a semianechoic chamber. Localization accuracy was quantified in mean angular error (MAE) and linear regression slope. RESULTS: Use of a CI for SSD subjects improved localization performance by slope for all stimuli ( p ≤ 0.0033) to a level that was equal to normal-hearing controls at 1 and 4 kHz ( p ≥ 0.2281). MAE was also significantly improved for SSD subjects using CI for BBN stimuli ( p ≪ 0.0001); however, no statistically significant improvement in MAE was seen for NBN ( p ≥ 0.5773) with CI use. Descriptive analysis of individual subject performance highlights the reasons for contradictory results. CONCLUSION: There is inherent challenge in characterizing localization benefit for individuals with CI for SSD. Our data demonstrate the limitations of utilization of average error as the sole metric for outcome benefit. We emphasize the importance of continued research investigating alternative outcome measures as we work toward a more refined understanding of the potential benefits and limitations of cochlear implantation for SSD.

A patient with 18p11.32-p11.21 deletion have monaural deafness caused by an inadequate haplodose of THOC1: A case report.

BACKGROUND: THOC1 mutation causes Deafness, autosomal dominant 86 [OMIM: 620280]. However, it has not been reported whether deletion of the THOC1 gene causes deafness. METHODS: Here, we report a 1-year-old girl with clinical features including Hypotonia, unilateral deafness in the right ear, and widening of lateral ventricles in 6 months. Gene mutations were identified by whole-exome sequencing. RESULTS: Through whole-exome sequencing, a deletion of 18p11.32-p11.21 contains the deletion of all THOC1 genes found in the patient but not in her parents' genomic DNA. The ClinGen Database Haplodose Insufficiency (HI) prediction tool determined that HI, THOC1 HI may cause unilateral deafness. Moreover, after 6 months of rehabilitation training, muscle tone returned to normal. However, at the age of 1 year, the patient developed symptoms of a large liver and hamartoma of both kidneys. CONCLUSION: From the above results, we propose that in our patient, THOC1 HI may cause unilateral deafness. Therefore, this study provides a new THOC1 deletion associated with unilateral deafness.

[Analysis of one-year outcomes after cochlear implantation in adults with single-sided deafness].

Objectives: To investigate the outcomes of cochlear implantation in Mandarin-speaking cochlear implant (CI) users with single-sided deafness (SSD). Methods: This study was a single-center prospective cohort study. Eleven Mandarin-speaking adult SSD patients who underwent CI implantation at Capital Medical University Beijing Tongren Hospital from August 2020 to October 2021 were recruited, including 6 males and 5 females, with the age ranging from 24 to 50 years old. In a sound field with 7 loudspeakers distributed at 180°, we measured root-mean-square error(RMSE)in SSD patients at the preoperative, 1-month, 3-month, 6-month, and 12-month after switch-on to assess the improvement of sound source localization. The Mandarin Speech Perception (MSP) was used in the sound field to test the speech reception threshold (SRT) of SSD patients under different signal-to-noise locations in a steady-state noise under conditions of CI off and CI on, to reflect the head shadow effect(SSSDNNH), binaural summation effect(S0N0) and squelch effect(S0NSSD). The Tinnitus Handicap Inventory (THI) and the Visual Analogue Scale (VAS) were used to assess changes in tinnitus severity and tinnitus loudness in SSD patients at each time point. The Speech, Spatial and Qualities of Hearing Scale(SSQ) and the Nijmegen Cochlear Implantation Scale (NCIQ) were used to assess the subjective benefits of spatial speech perception and quality of life in SSD patients after cochlear implantation. SPSS 19.0 software was used for statistical analysis. Results: SSD patients showed a significant improvement in the poorer ear in hearing thresholds with CI-on compared with CI-off; The ability to localize the sound source was significantly improved, with statistically significant differences in RMSE at each follow-up time compared with the preoperative period (P<0.05). In the SSSDNNH condition, which reflects the head shadow effect, the SRT in binaural hearing was significantly improved by 6.5 dB compared with unaided condition, and the difference was statistically significant (t=6.25, P=0.001). However, there was no significant improvement in SRT between the binaural hearing condition and unaided conditions in the S0N0 and S0NSSD conditions (P>0.05). The total score of THI and three dimensions were significant decreased (P<0.05). Tinnitus VAS scores were significantly lower in binaural hearing compared to the unaided condition (P<0.001). The total score of SSQ, and the scores of speech and spatial dimensions were significant improved in binaural hearing compared to the unaided condition (P<0.001). There was no statistical difference in NCIQ questionnaire scores between preoperative and postoperative (P>0.05), and only the self-efficacy subscore showed a significant increase(Z=-2.497,P=0.013). Conclusion: CI could help Mandarin-speaking SSD patients restore binaural hearing to some extent, improve sound localization and speech recognition in noise. In addition, CI in SSD patients could suppress tinnitus, reduce the loudness of tinnitus, and improve subjective perceptions of spatial hearing and quality of life.

[Effects of cochlear implantation on tinnitus in patients with single-sided deafness and asymmetrical hearing loss].

Objective:To evaluate the effects of cochlear implantation in patients with single-sided deafness（SSD） and asymmetrical hearing loss（AHL）. Methods:Seventeen Mandarin-speaking CI patients diagnosed as SSD/AHL were recruited in our study. The Tinnitus Handicap Inventory（THI） and the Visual Analogue Scale（VAS） were used to assess changes in tinnitus distress and tinnitus loudness in SSD patients at each time point（pre-operation and post-operation）. Results:The THI score and all 3 dimensions were significant decreased with CI-on than pre-operation（P<0.05）. Tinnitus VAS scores were also decreased, and VAS scores were lower with CI-on than with CI-off, and were both significantly different at each time point after CI switch-on（P<0.05）. Conclusion:CI could help SSD/AHL patients to suppress tinnitus and reduce the loudness of tinnitus. However, CI should not be a treatment of tinnitus.

Comparative Effectiveness of Personal Sound Amplification Products Versus Hearing Aids for Unilateral Hearing Loss: A Prospective Randomized Crossover Trial.

BACKGROUND: This study compared hearing outcomes with use of personal sound amplification products (PSAPs) and hearing aids (HAs) in patients with moderate to moderately severe unilateral hearing loss. METHODS: Thirty-nine participants were prospectively enrolled, and randomly assigned to use either one HA (basic or premium type) or one PSAP (basic or high-end type) for the first 8 weeks and then the other device for the following 8 weeks. Participants underwent a battery of examinations at three visits, including sound-field audiometry, word recognition score (WRS), speech perception in quiet and in noise, real-ear measurement, and self-report questionnaires. RESULTS: Functional gain was significantly higher with HAs across all frequencies (P < 0.001). While both PSAPs and HAs improved WRS from the unaided condition, HAs were superior to PSAPs. The speech recognition threshold in quiet conditions and signal-to-noise ratio in noisy conditions were significantly lower in the HA-aided condition than in the PSAP-aided condition, and in the PSAP-aided condition than in the unaided condition. Subjective satisfaction also favored HAs than PSAPs in questionnaires, Abbreviated Profile of Hearing Aid Benefit, International Outcome Inventory for Hearing Aids, and Host Institutional Questionnaire. CONCLUSION: While PSAPs provide some benefit for moderate to moderately severe unilateral hearing loss, HAs are more effective. This underscores the potential role of PSAPs as an accessible, affordable first-line intervention in hearing rehabilitation, particularly for individuals facing challenges in accessing conventional HAs.

Structural connectivity changes in unilateral hearing loss.

Network connectivity, as mapped by the whole brain connectome, plays a crucial role in regulating auditory function. Auditory deprivation such as unilateral hearing loss might alter structural network connectivity; however, these potential alterations are poorly understood. Thirty-seven acoustic neuroma patients with unilateral hearing loss (19 left-sided and 18 right-sided) and 19 healthy controls underwent diffusion-weighted and T1-weighted imaging to assess edge strength, node strength, and global efficiency of the structural connectome. Edge strength was estimated by pair-wise normalized streamline density from tractography and connectomics. Node strength and global efficiency were calculated through graph theory analysis of the connectome. Pure-tone audiometry and word recognition scores were used to correlate the degree and duration of unilateral hearing loss with node strength and global efficiency. We demonstrate significantly stronger edge strength and node strength through the visual network, weaker edge strength and node strength in the somatomotor network, and stronger global efficiency in the unilateral hearing loss patients. No discernible correlations were observed between the degree and duration of unilateral hearing loss and the measures of node strength or global efficiency. These findings contribute to our understanding of the role of structural connectivity in hearing by facilitating visual network upregulation and somatomotor network downregulation after unilateral hearing loss.