Understanding underlying pathological mechanisms is prerequisite for a sensible design of protective therapies against hearing loss. The triad of age-related, noise-generated, and drug-induced hearing loss ¬¬displays intriguing similarities in some cellular responses of cochlear sensory cells such as a potential involvement of reactive oxygen species and apoptotic and necrotic cell death. On the other hand, detailed studies have revealed that molecular pathways are considerably complex and, importantly, it has become clear that pharmacological protection successful against one form of hearing loss will not necessarily protect against another. This review will summarize pathological and pathophysiological features of age-related hearing impairment (ARHI) in human and animal models and address selected aspects of the commonality (or lack thereof) of cellular responses in ARHI to drugs and noise.

The triad of noise-generated, drug-induced, and age-related hearing loss is the major cause of acquired sensorineural hearing loss (ASNHL) in modern society. Although these three forms of hearing loss display similar underlying mechanisms, detailed studies have revealed the presence of sex differences in the auditory system both in human and animal models of ASNHL. However, the sexual dimorphism of hearing varies among noise-induced hearing loss (NIHL), ototoxicity, and age-related hearing loss (ARHL). Importantly, estrogen may play an essential role in modulating the pathophysiological mechanisms in the cochlea and several reports have shown that the effects of hormone replacement therapy on hearing loss are complex. This review will summarize the clinical features of sex differences in ASNHL, compare the animal investigations of cochlear sexual dimorphism in response to the three insults, and address how estrogen affects the auditory organ at molecular levels.

The objective of this study was to compare the efficacy of intratympanic steroid injection (ITS), hyperbaric oxygen (HBO), and combination therapy as salvage treatment in patients with sudden sensorineural hearing loss (SSNHL) after failure of systemic therapy. A historical cohort study. Academic medical center. One hundred three refractory SSNHL patients are enrolled. Among them, 35 received ITS alone (ITS group), 22 received HBO alone (HBO group), 19 received combined ITS and HBO (combined group), and 27 received no salvage therapies (control group). Hearing outcomes were determined by hearing gains in pure-tone average (PTA), recovery rate, and word recognition score (WRS) measured by audiometry before and after salvage therapies. Significant larger hearing gains in PTA were found in the ITS, HBO, and combined groups than the control group. The combination of ITS and HBO resulted in a significantly larger WRS improvement than the control group (p = 0.035) and larger hearing gains than the ITS and HBO groups in 250 Hz (p < 0.05). ITS, HBO, and combined therapy offered some benefits in hearing improvement. Combined ITS/HBO may result in a larger WRS improvement and recovery of hearing, especially in lower frequencies. Further randomized prospective studies are needed for confirmation.

Background: This study was performed to investigate the prognostic factors that influence hearing outcomes of children with cleft lip and palate after ventilation tube insertion. Methods: The authors retrospectively reviewed the hearing thresholds of 90 children with cleft lip and palate and performed univariate and multivariate analyses of five prognostic factors for hearing outcomes: age at palatoplasty, age at first ventilation tube insertion, timing of ventilation tube insertion, frequency of ventilation tube insertion, and type of cleft palate. Results: On univariate analysis, the authors found that older age at palatoplasty (p = 0.002), older age at first ventilation tube insertion (p = 0.025), and increased frequency of ventilation tube insertion (p = 0.048) were significant prognostic factors for poorer hearing outcomes in children with cleft lip and palate. Multiple logistic regression analysis showed that late palatoplasty (age older than 1 year) was the most influential factor for poor hearing outcome (OR, 2.83), followed by two or more ventilation tube insertions (OR, 1.94). Conclusion: The age at palatoplasty and frequency of ventilation tube insertion were found to be significant prognostic factors influencing hearing outcomes in children with cleft lip and palate. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, III.

The cause of sudden sensorineural hearing loss (SSNHL) remains unclear and therefore it is often considered as idiopathic. Sleep disturbance has been linked to SSNHL and circadian rhythm disruption, but the link between circadian rhythm disruption and SSNHL has never been investigated.In this study, we surveyed the sleep quality of 38 patients with SSNHL using a simple insomnia sleep questionnaire. The expression of circadian clock genes in peripheral blood (PB) leukocytes from 38 patients with SSNHL and 71 healthy subjects was accessed using real-time quantitative reverse transcriptase-polymerase chain reaction and validated using immunocytochemical staining.We found that 61.8% of patients with SSNHL suffered from insomnia before the insult of hearing loss. Besides, significantly decreased expression of PER1, CRY1, CRY2, CLOCK, BMAL1, and CKlε was found in PB leukocytes of patients with SSNHL when compared with healthy subjects. SSNHL patients with vertigo had significantly lower expression of CRY1 and CKlε than patients without vertigo symptoms. Our results imply the association of sleep disturbance and disrupted circadian rhythm in SSNHL.