Anaida S.

Hearing Loss

Hearing loss is an extremely common medical condition, progressing in incidence and severity with age. The affected population is also vast, varying between neonates to elderly patients, and is nearly omnipresent in the 70+ age group (Anastasiadou & Al Khalili, 2023). The human ear is the organ of hearing and equilibrium. It detects and analyzes sound by the mechanism of transduction, which is the process of converting sound waves into electrochemical impulses. Audition cannot take place adequately if the anatomy is abnormal (de Nava & Lasrado, 2023). Normal hearing function involves sound waves arriving at the auricle, passing through the external auditory canal, causing a vibration of the tympanic membrane. Vibration is then transmitted via the ossicles (malleus, incus, stapes) to the cochlea. Subsequently, hair cells inside the cochlea stimulate the eighth cranial nerve that transfers the stimuli to the brain. Processing of crude sounds occurs in the higher cortices of the brain, and this includes the comprehension of language (Anastasiadou & Al Khalili, 2023). Hearing loss can be conductive, sensorineural, or mixed. In this work we will focus on identifying the differences between conductive and sensorineural hearing loss. In addition, we will propose some necessary questions during the interview with patients to identify risk factors for hearing loss.

Differences between Conductive and sensorineural hearing loss

The main difference between conductive and sensorineural deafness lies in the location of the damage. Conductive hearing loss takes place with disruption of the transmission of the sound waves to the cochlea (Anastasiadou & Al Khalili, 2023). This diagnosis covers a variety of conditions. This is because a pathology anywhere from the pinna and the external acoustic meatus to the foot of the stapes bone can produce a conductive hearing loss (Sooriyamoorthy & De Jesus, 2023). The most common causes include abnormal formation of the auricle or helix, cerumen impaction, ear canal foreign bodies, otitis externa, dysfunction or fixation of the ossicular chain, and middle ear effusion. Cholesteatoma, a benign though locally destructive trapping of squamous debris arising from the tympanic membrane, as well as other benign or malignant tumors, can result in conductive hearing loss (Anastasiadou & Al Khalili, 2023).

For its part, sensorineural hearing loss (SNHL) usually results from problematic transmission of the stimuli at or after the cochlea. This may be a result of damage to the hair cells within the inner ear, the vestibulocochlear nerve, or the brain’s central processing centers (Tanna et al., 2023). The main difference between the two kinds of hearing loss, apart from the pathophysiological features, is that patients with conductive hearing loss perceive the sounds diminished, while SNHL patients may perceive the sounds diminished and distorted (Anastasiadou & Al Khalili, 2023). The identification of the cause and location of the damage for hearing loss is essential for the planning of treatment, whether conservative medical, surgical, with hearing aids or with cochlear implants as necessary (Anastasiadou & Al Khalili, 2023).

Useful questions for the patient to identify risk factors for hearing loss

There are several risk factors for hearing loss, which is why during the evaluation of patients, it is important to investigate the possibility of the existence of some of these factors, since prevention work is as or more important than treatment. For example, we must include in the interrogation questions about the family history of hearing loss to rule out hereditary diseases (Dang & Hsu, 2023). In the case of children in whom early detection of hearing impairment or loss is so important due to its impact on language development, the prenatal and perinatal history should be in-depth (n.d.).

One of the factors that must be asked about is exposure to noise, not only intense but also habitual or prolonged. Excessive occupational exposure to noise results in a well-recognized occupational hearing loss which is prevalent in many workplaces and now it is taken as a global problem (Hailu et al., 2024). We should also ask if you have had a history of head trauma or traumatic brain injury, falls, a history of ear infections, stroke, and certain chronic health conditions like diabetes, cardiovascular disease, and kidney disease (Dang & Hsu, 2023). Additionally, ear disorders such as Meniere disease, otosclerosis, and autoimmune inner ear disease elevate the risk of hearing loss (Dang & Hsu, 2023).

Certain medications, known as ototoxic medications, can also contribute to hearing impairment. These include aminoglycosides, erythromycin, tetracycline, vancomycin, phosphodiesterase inhibitors, certain chemotherapeutic agents like cisplatin and 5-fluorouracil, and heavy metals including lead, mercury, cadmium and arsenic (Rizk et al., 2020). Adults expressing concerns about hearing loss or displaying signs of hearing impairment should undergo screening for early detection and appropriate intervention (Dang & Hsu, 2023)

In summary, hearing loss can be conductive, sensorineural or mixed. Health professionals must know how to recognize the differences between conductive and sensorineural hearing loss for effective management of these disorders. Early diagnosis and identification of risk factors for hearing loss is important for better treatment and prognosis. Hearing loss promotion and prevention efforts play an essential role in avoiding or reducing the appearance or progression of hearing loss.

References

Anastasiadou, S., & Al Khalili, Y. (2023). Hearing Loss. StatPearls Publishing.

Dang, J. C., & Hsu, N. M. (2023). Hearing loss screening guidelines. StatPearls Publishing.

de Nava, A. S. L., & Lasrado, S. (2023). Physiology, Ear. StatPearls Publishing.

Hailu, A., Zeleke, B., Ermias, Z., Duguma, F. K., Dula, S., Abaya, S. W., Shegen, S. M., Tucho, G. T., & Afata, T. N. (2024). Prevalence and associated factors of noise-induced hearing loss among workers in Bishoftu Central Air Base of Ethiopia. Scientific Reports, 14(1), 1–10. https://doi.org/10.1038/s41598-024-56977-4

Rizk, H. G., Lee, J. A., Liu, Y. F., Endriukaitis, L., Isaac, J. L., & Bullington, W. M. (2020). Drug‐induced ototoxicity: A comprehensive review and reference guide. Pharmacotherapy, 40(12), 1265–1275. https://doi.org/10.1002/phar.2478

Sooriyamoorthy, T., & De Jesus, O. (2023). Conductive hearing loss. StatPearls Publishing.

Tanna, R. J., Lin, J. W., & De Jesus, O. (2023). Sensorineural Hearing Loss. StatPearls Publishing.

 (N.d.). Aap.org. Retrieved August 6, 2024, from https://publications.aap.org/pediatrics/article/152/3/e2023063288/193755/Hearing-Assessment-in-Infants-Children-and?autologincheck=redirected