Objective: To systematically appraise the implementation of cochlear implantation (CI) in Usher Syndrome (USH) Types 1, 2, and 3 patients, and analyze who would benefit from CI. Data Sources: A comprehensive search of PubMed, Embase, CINAHL, and Cochrane Library electronic databases from inception through June 2020 was performed. There were no language restrictions. Study Selection: The PRISMA strategy was followed. Included studies discuss USH patients who underwent CI regardless of age, nationality, or clinical subtype. All included studies report post-implantation functional, cognitive, or quality of life outcomes. Only reviews were excluded. Results: Fifteen studies met the inclusion criteria. USH patients experienced improvements in PTA and speech perception and expression outcomes after CI, as well as improvements in phonological memory and quality of life measures. Overall, patients implanted at younger ages outperformed older patients in audiological testing. Similarly, patients with prolonged auditory deprivation had relatively poor performance outcomes in sentence recognition and speech detection following CI. Conclusions: Most USH patients benefit from CI. USH patients who undergo CI at younger ages generally achieve better hearing, speech, and cognitive outcomes. CI at older ages can still prove beneficial if appropriate auditory amplification is started at the right time. Further research is warranted to fill the gap in understanding regarding the gene mutations underlying the pathophysiology of USH that have favorable CI outcomes as well as the optimal time to perform CI.

Recent advancements in stem cell therapy have led to an increased interest within the auditory community in exploring the potential of mesenchymal stem cells (MSCs) in the treatment of inner ear disorders. However, the biocompatibility of MSCs with the inner ear, especially when delivered non-surgically and in the immunocompetent cochlea, is not completely understood. In this study, we determined the effect of intratympanic administration of rodent bone marrow MSCs (BM-MSCs) on the inner ear in an immunocompetent rat model. The administration of MSCs did not lead to the generation of any oxidative stress in the rat inner ear. There was no significant production of proinflammatory cytokines, tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6 and IL-12, due to BM-MSCs administration into the rat cochlea. BM-MSCs do not activate caspase 3 pathway, which plays a central role in sensory cell damage. Additionally, transferase dUTP nick end labeling (TUNEL) staining determined that there was no significant cell death associated with the administration of BM-MSCs. The results of the present study suggest that trans-tympanic administration of BM-MSCs does not result in oxidative stress or inflammatory response in the immunocompetent rat cochlea.

Background: Electrode insertion trauma (EIT) during cochlear implantation (CI) can cause loss of residual hearing. L-N-acetylcysteine (L-NAC) and dexamethasone (Dex) have been individually shown to provide otoprotection albeit at higher concentrations that may be associated with adverse effects. Objective/Aims: The aim of this study is to determine whether L-NAC and Dex could be combined to decrease their effective dosage. Materials and Methods: The organ of Corti (OC) explants were divided into various groups: 1) control; 2) EIT; 3) EIT treated with different concentrations of Dex; 4) EIT treated with different concentrations of L-NAC; 5) EIT treated with L-NAC and Dex in combination. Hair cell (HC) density, levels of oxidative stress, proinflammatory cytokines and nitric oxide (NO) was determined. Results: There was a significant loss of HCs in explants subjected to EIT compared to the control group. L-NAC and Dex in combination was able to provide significant otoprotection at lower concentrations compared to individual drugs. Conclusions and Significance: A combination containing L-NAC and Dex is effective in protecting sensory cells at lower protective doses than each compound separately. These compounds can be combined allowing a decrease of potential side effects of each compound and providing significant otoprotection for EIT.

The medial olivocochlear efferent (MOCE) branch synapses with outer hair cells (OHCs), and the efferent pathway can be activated via a contralateral acoustic stimulus (CAS). The activation of MOCE can change OHC motile responses and convert signals that are capable of controlling the sensitivity of the peripheral hearing system in a frequency-specific manner. The aim of this study was to examine the MOCE system activity in professional musicians using transient evoked otoacoustic emission test and CAS. Musician group showed stronger suppression in all frequency bands in the presence of CAS.

Recent community-based studies have identified sleep deprivation (SD) as an important modifiable risk factor for hypertension However, the underlying mechanisms linking SD to hypertension remain elusive. Thus, this study investigates blood pressure (BP) responses to cardiac autonomic stress tests in the presence of SD. Furthermore, we analyzed vascular inflammatory biomarkers as a possible underlying factor linking SD to increased BP. Ten healthy male volunteers (age, 21.6±1.2 years) underwent repeated autonomic stress tests for three consecutive days (baseline, SD, and recovery). The autonomic stress tests included the Valsalva maneuver, mental arithmetic, isometric handgrip, and cold pressor tests. Each day, resting BPs were measured, venous blood samples were collected for intercellular adhesion molecule 1, vascular cell adhesion molecule 1, and E-selectin measurements, and stress tests were performed between 0900 and 1100. Ambulatory BP was recorded during the entire SD period (24 h). One-night SD abolished BP reactivity to the Valsalva maneuver, isometric hand grip, and cold pressor tests, which returned after recovery sleep. Ambulatory BP monitoring showed that the mean systolic and diastolic BPs were 121.1±8.5 mm Hg and 72.8±6.3 mm Hg, respectively, between 0700 and 2300 and 120.3±9.6 mm Hg and 74.1±6.1 mm Hg, respectively, between 2300 and 0700 during the SD day (p>0.05 for both). Vascular inflammatory markers seemed unrelated to BP changes. Acute SD altered BP responses to cardiac autonomic stress tests in healthy men without affecting resting BP levels. SD led to a non-dipping pattern in BP oscillation. Collectively, these findings highlight the importance of sleep in regulating BP.

Perception of acoustic details in the speech signal is important for speech sound development. The medial olivocochlear pathway, a part of the auditory efferent system, plays a role in stimulus-related control of the cochlea. One clinical tool to evaluate medial olivocohlear activity, which is thought to improve speech perception in noise, is the suppression of otoacoustic emissions. To investigate suppression of transient evoked otoacoustic emissions (TEOAEs) in children with phonological disorder in comparison with typically developing controls. Case-control study. Twenty-three children with phonological disorder (five to ten years old) and 21 age- and sex-matched (p>0.05) controls participated in the study. Participants had pure-tone thresholds ≤ 15 dB HL and normal middle ear functions. Transient evoked otoacoustic emissions (TEOAE) with and without contralateral acoustic stimulation were measured. Although the mean TEAOE suppressions were lower in the phonological disorder group compared with controls, these differences were not statistically significant (p>0.05). No left/right ear asymmetry of TEOAE suppression was detected in the either the phonological disorder or control group (p>0.05). Children with phonological disorder did not show alterations in MOC functioning in the medial olivocochlear activity as measured by the contralateral suppression of TEOAEs.