A lot of people suffer from hearing loss which can either be complete or partial. Some can be treated and managed, while some cannot be treated and managed. The ear is vital to humans as it is good for both hearing and balancing.It is an important sense and is needed to listen and send hearing information to the brain for interpretation and understanding. In this post, I will be looking into hearing loss and its causes.
The ear is made up of three segments which are the outer ear, the middle ear, and the inner ear. The outer ear comprises the pinna, the auditory canal, the tympanic membrane, and the Eustachian tube which connects the throat to the middle ear. In the middle ear are the malleus, incus, and stapes which connect the tympanic membrane to the inner ear. The inner ear comprises semicircular canals which are responsible for head movement includes the vestibular system and the cochlear is responsible for sound vibration to the nerve signal. This translate to the vestibular cochlear nerve which transmit nerve signals from the cochlear to the brain.
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Hearing loss can be categorized into conductive and sensorineural hearing loss. When there is a problem with sound traveling into the inner ear, then that is Conductive Hearing Loss which can be an effect of a defect that can range from the external ear to the ossicles. With Conductive hearing loss, the sensory system might be working correctly but then the sound doesn't find its way to the sensory system. To understand this, if there is an earplug in the ear, it would prevent the hearing of the person as the soundwave does not reach the sensory system. With Sensorineural Hearing Loss, the vestibulocochlear nerve or sensory system is not functioning properly thereby not transmitting sound waves to the brain when the sound reaches the inner ear.
Ear loss can occur gradually where people start to notice that they are not able to hear properly. The patient starts to become concerned about dimentia when they actually have hearing loss. hearing loss can also be sudden where there is a complete loss within 72 hours. Patient who exhibit hearing loss will experience symptoms such as tinnitus, vertigo, pain, discharge, and other potential neurological symptoms. Patients with hearing loss may also suffer from dimentia and hearing aids may reduce such risk of development. When people develop hearing loss, it is important to carry out some tests such as the Weber's and Rinne's test.
Weber's and Rinne's test is used to differentiate Conductive Hearing Loss and Sensorineural Hearing Loss. These tests are performed with the tunning fork. With Weber's test, the tuning fork is struck to make it vibrate and hum with the palm or the knee and placed on the patients center head asking the patient if they can hear the sound and at which ear they can hear it or where is it loudest at. If the patient hears the sound on both ears equally then the patient is fine. If the sound is louder in the normal ear and less loud in the affected ear, then it is a sensorineural hearing loss. In conductive hearing loss, the sound is louder in the affected ear and less loud in the non-affected ear because the affected ear has become more sensitive as a result of sound not reaching the inner ear.
When it comes to Rinne's test, air conduction is tested for. The vibrating tunning fork is placed at the mastoid process so as to be able to test for conduction by the bones. The cochlear hears the humming noise directly from this place. When the patient can't hear the humming of the tunning fork, the tunning fork should be placed close to the ear to be sure if teh patient can hear the sounds. Normally, in Rinne's positive test, the patient should be able to hear to sound with bone conduction and can hear the sound through air conduction as the air conduction is more sensitive than bone conduction. With Rinne's negative test, bone conduction is better than air conduction as the sound is not heard frrom air conduction which is the use to identify conductive hearing loss.
Sensorineural hearing loss can be caused by be sudden which is a hearing loss less than 72 hours, Acoustic neuroma, presbycusis which is associated with age, menieres disease, exposure to noise, Labyrinthitis, infections like meningitis, and neurological conditions such as stroke, brain tumor, and multiple sclerosis. Sensorineural hearing loss can also be caused by medications such as loop diuretics, chemotherapy drugs, and Aminoglycoside antibiotics (gentamycine). Conductive hearing loss can be caused by blockage of the ear canal by ear wax, foriegn body, infections that block ear canal, fluid in the middle ear, eustachian tube dysfunction, otosclerosis, perforated tympanic membrane, tumors, and cholesteatoma. When treating a conductive hearing loss, it has to do with correcting whatever wrong or malformation in the ear. If the blockage is caused by an infection, then it is treated with antibiotics. Hearing aid can also be used to help amplify the hearing of the person if they are aged. With Sensorineural hearing loss can be addressed at different levels such as with hearing aids in children, or sensor implant. If it as caused by autoimmune diseases, long term steroids is given to the patient, and if it is caused by noise pollution, then the noise should be reduced.
Reference
- https://www.ncbi.nlm.nih.gov/books/NBK563267/
- https://www.asha.org/public/hearing/sensorineural-hearing-loss/
- https://www.healthyhearing.com/report/50276-Common-causes-of-sensorineural-hearing-loss
- https://www.ncbi.nlm.nih.gov/books/NBK565860/
- https://www.ncbi.nlm.nih.gov/books/NBK542323/
- https://www.asha.org/articles/untreated-hearing-loss-in-adults/
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6457651/