OBJECTIVE: Sound localization plays a crucial role in our daily lives, enabling us to recognize voices, respond to alarming situations, avoid dangers, and navigate towards specific signals. However, this ability is compromised in patients with Single-Sided Deafness (SSD) and Asymmetric Hearing Loss (AHL), negatively impacting their daily functioning. The main objective of the study was to quantify the degree of sound source localization in patients with single-sided deafness or asymmetric hearing loss using a Cochlear Implant (CI) and to compare between the two subgroups.
METHODS: This was a prospective, longitudinal, observational, single-center study involving adult patients diagnosed with profound unilateral or asymmetric sensorineural hearing loss who underwent cochlear implantation. Sound localization was assessed in a chamber equipped with seven speakers evenly distributed from -90º to 90º. Stimuli were presented at 1000 Hz and intensities of 65 dB, 70 dB, and 75 dB. Each stimulus was presented only once per speaker, totaling 21 presentations. The number of correct responses at different intensities was recorded, and angular error in degrees was calculated to determine the mean angular distance between the patient-indicated speaker and the speaker presenting the stimulus. Both assessments were conducted preoperatively without a cochlear implant and two years post-implantation.
RESULTS: The total sample comprised 20 patients, with 9 assigned to the SSD group and 11 to the AHL group. The Preoperative Pure Tone Average (PTA) in free field was 31.7 dB in the SSD group and 41.8 dB in the AHL group. There was a statistically significant improvement in sound localization ability and angular error with the use of the cochlear implant at all intensities in both SSD and AHL subgroups.
CONCLUSIONS: Cochlear implantation in patients with SSD and AHL enhances sound localization, reducing mean angular error and increasing the number of correct sound localization responses.

This study aimed to report quality of life (QoL) scores in unilateral cochlear implant (CI) users and to generate guidance for clinicians on using QoL measures to individualize CI counselling and rehabilitation and to increase access to CIs as a mode of rehabilitation. Participants (n = 101) were unilateral CI users with single-sided deafness (SSD; n = 17), asymmetrical hearing loss (AHL; n = 26), or bilateral hearing loss (Uni; n = 58). Generic QoL was assessed via the Health Utilities Index (HUI-3), and disease-specific QoL was assessed via the Speech, Spatial, and Qualities of Hearing scale (SSQ12) and Nijmegen CI Questionnaire (NCIQ) at preimplantation and at 6 and 12 months of CI use. All groups had significantly increased HUI-3 scores at both intervals. The SSD group showed significant benefit on the SSQ12 at visit 3, the AHL group showed significant benefit on the SSQ12 and most NCIQ subdomains at both intervals, and the Uni group showed significant benefit with both tests at both intervals. Unilateral CI recipients demonstrate improved QoL within the first 12 months of device use. Regular assessment with generic and disease-specific questionnaires has the potential to play an important role in personalizing treatment and possibly in increasing access to CI provision.

Cochlear implantation (CI) is used in patients with severe-to-profound hearing loss when hearing aids provide limited or no benefit for speech perception. Studies on this topic reported tinnitus reduction as a common side effect of the electrical activation after cochlear implantation. So far, it is unclear what the effect is when patients do receive their implant primarily because of tinnitus complaints.
To assess the effectiveness of the electrical stimulation with a cochlear implant in patients with tinnitus as a primary complaint, by systematically reviewing the literature.
Two independent authors identified studies, extracted data and assessed risk of bias of included studies. Original studies reporting outcomes of electrical stimulation by cochlear implantation for primarily tinnitus (defined as severe or incapacitating distress levels) were included, if they reported a follow-up of at least three months. The pre- and post-implantation tinnitus distress scores on single and/or multi-item questionnaires of the included studies were extracted.
In total, 4091 unique articles were retrieved. After screening titles, abstracts and full texts, we included seven prospective cohort studies (105 subjects in total, range: 10-26). All studies had considerable risks of bias. All tinnitus patients in the included studies had asymmetrical hearing loss or single-sided deafness. A statistically significant tinnitus distress improvement based on tinnitus questionnaire scores was found in every study.
Our systematic review reveals that electrical stimulation by cochlear implants in patients with a primary complaint of tinnitus has a positive impact on tinnitus distress. Nevertheless, only small sample sizes were found and studies showed considerable risks of bias.a.

To describe the pre-implant audiometric profile of adult cochlear implant (CI) recipients to investigate whether current binaural candidacy requirements prevent access to patients who could benefit from CI.
Retrospective case series.
Retrospective review from 2016 to 2018 evaluating preoperative pure-tone thresholds and speech perception scores in the ipsilateral and contralateral ear.
A total of 252 adult CI recipients undergoing 270 implants were identified. Median age at time of implantation was 70.5 years (IQR 61.3-78.3) for those undergoing unilateral implantation and 59.0 (IQR 48.0-72.3) for those undergoing bilateral implantation (P < .01). For unilateral implantation, median pre-implantation speech perception performance in the ear to be implanted was 8.0% (IQR 0%-26.0%) for CNC word scores, and 9.0% (IQR 0%-34.0%) for AzBio sentence scores in quiet. Median speech perception performance in the contralateral ear was 36.0% (IQR 14.0%-60.0%) on CNC word scores, and 48.5% (IQR 17.5%-76.0%) on AzBio sentence tests. Speech perception scores were significantly different between ears for word and sentence tests (P < .01). Patients older than age 65 were significantly less likely to undergo bilateral implantation (P = .03).
Adult CI recipients exhibit substantially poorer pre-implant speech perception scores than the commonly utilized ipsilateral qualifying threshold of 50% on sentence testing. Yet, existing insurance paradigms limit patients by excessively stringent binaural best-aided requirements. This limitation likely leads to worse device performance as patients often wait years for their binaural hearing to qualify while their ear to be implanted potentially experiences an unnecessarily extended duration of deafness. Older patients also experience a unique delay in referral for cochlear implantation.
3- Retrospective review Laryngoscope, 131:E2007-E2012, 2021.

Objective: Recent changes to cochlear implant (CI) candidacy criteria have led to the inclusion of candidates with greater levels of hearing in the contralateral and/or implanted ear. This study assessed the impact of various hearing loss configurations on CI uptake rates (those assessed as eligible for CI, who proceed to CI).Design: Retrospective cohort study.Study sample: Post-lingually deaf adult CI candidates (n = 619) seen at a Western Australian cochlear implant clinic.Results: An overall CI uptake rate of 44% was observed. Hearing loss configuration significantly impacted uptake rates. Uptake rates of 62% for symmetrical hearing loss, 48% for asymmetrical hearing loss (four-frequency average hearing loss (4FAHL) asymmetry ≤60 dB), 25% for highly asymmetrical hearing loss (4FAHL asymmetry >60 dB), 38% for hearing losses eligible for electric-acoustic stimulation, and 22% for individuals with single-sided hearing loss were observed. Hearing loss configuration and age were both significant factors in relation to CI uptake although the impact of age was limited.Conclusion: CI clinics who apply or are considering applying expanded CI candidacy criteria within their practice should be aware that candidates with greater levels of residual hearing in at least the contralateral ear are less likely to proceed to CI.

Objective: For a group of bimodal subjects with moderate to severe hearing loss contralateral to the cochlear implant (CI), the bimodal benefit of the hearing aid (HA) gain prescriptions DSL v5.0, NAL-NL2 and the recipients\' own gain setting were assessed.Design: Speech perception in quiet and in noise as well as self-reported ratings of benefit were determined for all three gain-settings. Speech tests were performed in the bimodal, the HA alone and the CI alone condition. The bimodal benefit was assessed for each prescription as the difference score of the bimodal condition and the better ear.Study Sample: Twenty adults with post-lingual hearing loss.Results: Speech perception with DSL v5.0 was significantly higher compared to NAL-NL2 and the own prescription in both quiet and noise. The median bimodal benefit was highest for DSL v5.0 with an average of 15 percentage points for both words in quiet and sentences in noise.Conclusions: DSL v5.0 and NAL-NL2 are both suitable for HA fitting in bimodal users. For subjects with moderate to severe hearing loss and HA experience contralateral to the implanted side, DSL v5.0 may provide better speech perception and bimodal benefit.

The aim of this document is to improve the management and the treatment of unilateral or asymmetrical hearing loss in children. One in one thousand newborn infants has unilateral hearing loss and this prevalence increases with age, due to cases of acquired and delayed-onset hearing loss. Although the impact on the development and learning processes of children of these kinds of hearing loss have usually been minimized, if they are not treated they will impact on language and speech development, as well as overall development, affecting the quality of life of the child and his/her family. The outcomes of the review are expressed as recommendations aimed at clinical diagnosis and therapeutic improvement for unilateral or asymmetrical hearing loss.

The article shows 2 cases of unusual presentation of acute acoustic trauma and blast injury due to occupational exposure. In the case of both patients the range of impaired frequencies in pure tone audiograms was atypical for this kind of causative factor. Both patients had symmetrical hearing before the accident (which was confirmed by provided results of hearing controls during their employment). A history of noise/blast exposure, the onset of symptoms directly after harmful exposure, symmetrical hearing before the trauma documented with audiograms, directed initial diagnosis towards acoustic/blast trauma, however, of atypical course. Acute acoustic and blast trauma and coexisting acoustic neuroma (AN) contributed to, and mutually modified, the course of sudden hearing loss. In the literature there are some reports pointing to a higher sensitivity to acoustic trauma in the case of patients with AN and, on the other hand, indicating noise as one of the causative factors in AN. Int J Occup Med Environ Health 2018;31(3):361-369.

BACKGROUND: Noise-induced hearing loss is one of the most common forms of sensorineural hearing loss, is a major health problem, is largely preventable and is probably more widespread than revealed by conventional pure tone threshold testing. Noise-induced damage to the cochlea is traditionally considered to be associated with symmetrical mild to moderate hearing loss with associated tinnitus; however, there is a significant number of patients with asymmetrical thresholds and, depending on the exposure, severe to profound hearing loss as well.
METHODS: Recent epidemiology and animal studies have provided further insight into the pathophysiology, clinical findings, social and economic impacts of noise-induced hearing loss. Furthermore, it is recently shown that acoustic trauma is associated with vestibular dysfunction, with associated dizziness that is not always measurable with current techniques. Deliberation of the prevalence, treatment and prevention of noise-induced hearing loss is important and timely. Currently, prevention and protection are the first lines of defence, although promising protective effects are emerging from multiple different pharmaceutical agents, such as steroids, antioxidants and neurotrophins.
CONCLUSIONS: This review provides a comprehensive update on the pathophysiology, investigations, prevalence of asymmetry, associated symptoms, and current strategies on the prevention and treatment of noise-induced hearing loss.

CONCLUSIONS: The present study revealed that various etiologies are involved in single-sided deafness (SSD), and that the cause of SSD and asymmetrical hearing loss (AHL) differed greatly between congenital/early-onset cases and adult cases. Clarification of the etiology is the first step toward providing appropriate intervention.
OBJECTIVE: The study aimed to clarify the etiology of SSD and AHL patients.
METHODS: The etiology of a total of 527 SSD or AHL patients who visited Shinshu University Hospital between 2006 and 2016 were analyzed by imaging as well as serological tests for mumps virus, and CMV DNA testing.
RESULTS: In our cohort of congenital/early-onset SSD (n = 210), the most prevalent cause in children was cochlear nerve deficiency (43.7%; 87 of 199 patients undergoing CT and/or MRI), followed by CMV infection, mumps infection, anomalies of the inner ear, ANSD, and other rare etiologies. In contrast, half of the adult SSD patients presented with idiopathic sensorineural hearing loss, followed by various types of otitis media, cerebellopontine angle tumor and other rare etiologies.