Anatomy and physiology of the external, middle and inner ear

Effect of External Ear Deformity on Hearing in Wrestlers

PURPOSE

Cauliflower ear in wrestlers can lead to hearing impairment. This study primarily aims to assess the hearing of wrestlers with bilateral cauliflower ears and determine their external ear canal (EEC) resonance frequencies. Our second aim is to evaluate their hearing quality, speech, and spatial perception.

METHOD

This study included 28 male wrestlers aged 18-35 years with bilateral cauliflower ears, as well as 27 male participants in the control group with no wrestling history. The participants' hearing thresholds were determined across the frequency range of 125-16000 Hz for air-conduction and 500-4000 Hz for bone conduction. EEC resonance frequencies were measured. Additionally, all participants completed the Turkish version of the Speech, Spatial, and Qualities of Hearing Scale (SSQ) questionnaire.

RESULTS

Wrestlers with cauliflower ears exhibited significantly higher hearing thresholds, particularly at frequencies above 4000 Hz (p < .05). Analysis of EEC resonance showed a shift to higher frequencies in the second resonance peak of the right ear (p < .001) and the first resonance peak of the left ear (p = .045). SSQ scores revealed that wrestlers had higher spatial perception (p = .046), hearing quality (p = .004), and general scores (p = .042) in comparison to the control group.

CONCLUSIONS

Blunt traumas in wrestlers, leading to cauliflower ear, can result in hearing loss. Moreover, deformities in the external ear affect the resonance frequencies of the EEC. Therefore, it is crucial to advocate for the use of ear protection equipment among wrestlers. When fitting hearing aids, attention should be given to changes in the EEC resonance frequency.

Enhancement of Trans-Tympanic Drug Delivery by Pharmacological Induction of Inflammation

Drug delivery directly across the tympanic membrane (TM) could eliminate systemic exposure to antibiotics prescribed for otitis media, the most common reason for pediatricians to prescribe antibiotics. Here, we hypothesized that inducing inflammation of the TM could enhance drug flux across the TM. We demonstrated that the flux of ciprofloxacin across the TM was greatly increased by treatment with the proinflammatory agent histamine. That enhancement was blocked by concurrent treatment with blockers of histamine receptor 1. Treatment of the TM with histamine was able to enhance drug flux sufficiently to eradicate otitis media in vivo in chinchillas, but only if the histamine was applied prior to treatment with antibiotics.

Hearing loss drug discovery and medicinal chemistry: Current status, challenges, and opportunities

Hearing loss is a severe high unmet need condition affecting more than 1.5 billion people globally. There are no licensed medicines for the prevention, treatment or restoration of hearing. Prosthetic devices, such as hearing aids and cochlear implants, do not restore natural hearing and users struggle with speech in the presence of background noise. Hearing loss drug discovery is immature, and small molecule approaches include repurposing existing drugs, combination therapeutics, late-stage discovery optimisation of known chemotypes for identified molecular targets of interest, phenotypic tissue screening and high-throughput cell-based screening. Hearing loss drug discovery requires the integration of specialist therapeutic area biology and otology clinical expertise. Small molecule drug discovery projects in the global clinical portfolio for hearing loss are here collated and reviewed. An overview is provided of human hearing, inner ear anatomy, inner ear delivery, types of hearing loss and hearing measurement. Small molecule experimental drugs in clinical development for hearing loss are reviewed, including their underpinning biology, discovery strategy and activities, medicinal chemistry, calculated physicochemical properties, pharmacokinetics and clinical trial status. SwissADME BOILED-Egg permeability modelling is applied to the molecules reviewed, and these results are considered. Non-small molecule hearing loss assets in clinical development are briefly noted in this review. Future opportunities in hearing loss drug discovery for human genomics and targeted protein degradation are highlighted.

Nanocarriers for drug delivery to the inner ear: Physicochemical key parameters, biodistribution, safety and efficacy

Despite the high incidence of inner ear disorders, there are still no dedicated medications on the market. Drugs are currently administered by the intratympanic route, the safest way to maximize drug concentration in the inner ear. Nevertheless, therapeutic doses are ensured for only a few minutes/hours using drug solutions or suspensions. The passage through the middle ear barrier strongly depends on drug physicochemical characteristics. For the past 15 years, drug encapsulation into nanocarriers has been developed to overcome this drawback. Nanocarriers are well known to sustain drug release and protect it from degradation. In this review, in vivo studies are detailed concerning nanocarrier biodistribution, their pathway mechanisms in the inner ear and the resulting drug pharmacokinetics. Key parameters influencing nanocarrier biodistribution are identified and discussed: nanocarrier size, concentration, surface composition and shape. Recent advanced strategies that combine nanocarriers with hydrogels, specific tissue targeting or modification of the round window permeability (cell-penetrating peptide, magnetic delivery) are explored. Most of the nanocarriers appear to be safe for the inner ear and provide a significant efficacy over classic formulations in animal models. However, many challenges remain to be overcome for future clinical applications.