Medical Term Project on Disorders of the Inner Ear


My name is Chelsea and I am going to be talking
about disorders of the inner ear – causes, symptoms, and treatment. So inner ear disorders can be caused by both
pre- slash perinatal causes, which means before or around the time of birth, and postnatal
causes, which means after birth to adulthood. Some pre- slash perinatal causes are malformations,
genetics, infections, and Rh incompatibility. So malformations are an interruption in development.
The severity of the hearing disorder depends on when in development the malformation occurred.
So, it may only be a common cavity rather than a spiral, or only a portion of the cochlea
turns rather than the entire cochlea. There are three types of aplasias, which is a term
for defective development. Either complete failure of development of the inner ear, incomplete
development of the inner ear, or degeneration of the cochlear membrane. So genetics – many of you know that chromosomes
are strands of DNA, and genes are located within each chromosome. A mutation is a change
in the sequence of a DNA molecule. Genes turn on and off at different times, and if a gene
does not turn on, or does not work properly, it can lead to problems with structure and
function. So if the DNA of a gene is mutated, the gene may not turn on. Thus, it does not
send the message to make certain proteins, and these particular proteins are not made.
For example, if protein channels in outer hair cells aren’t formed, outer hair cells
won’t function properly, leading to hearing loss. Infections. So there is syphilis, a bacterial
infection that is sexually transmitted. Toxoplasmosis, is a parasite contracted by eating uncooked
meat or touching cat feces. Other, so HIV can be considered ‘other’ – it can be passed
to the fetus during breastfeeding, delivery, or occasionally in utero. There’s rubella,
which is a viral airborne infection. Cytomegalovirus, which is a viral infection that is a member
of the herpes family; and then there’s herpes which is a viral infection that is sexually
transmitted and if the infection is active during the time of vaginal delivery, it may
be passed to the infant. So Rh incompatibility. We have A, B, AB, and
O as our blood types, which are proteins specific to blood type that sit on the surfaces of
red blood cells. Presence of the Rh protein on surface of red blood cells – so if you
have the Rh protein you are Rh positive, and if you don’t, you are Rh negative. So when
a mom is Rh positive and the fetus is Rh negative, it will be fine at the first pregnancy, but
if the fetal blood mixes with the mom’s blood then the mom recognizes the Rh positive protein
as foreign and begins producing antibodies against it. So if at the next pregnancy the
fetus is also Rh positive, her Rh antibodies attack the fetus and enter the bloodstream. Some post-natal causes are ear and head trauma,
Meniere’s disease, and acoustic neuroma. So barotrauma can the round window to rupture
or the stapes footplate to pop out of the oval window, causing hearing loss and vertigo.
Acoustic trauma can cause temporary or permanent sensorineural hearing loss due to outer hair
cell damage. Head trauma, diving, and flying can cause hearing loss; and there’s also noise-induced
hearing loss, which means the severity of noises can cause hearing loss depending on
how severe. Meniere’s disease is a disease that has symptoms
with an abrupt onset. There is usually hearing loss in the lower frequency sounds, tinnitus,
vertigo, and feeling of pressure in the ears. The cause is uncertain but it is thought to
be caused by fluid in the inner ear, and treatments vary. Acoustic neuroma is a benign tumor that stems
from the auditory nerve, and it can cause hearing impairment in the inner ear. Presbycusis is a sensorineural hearing loss
due to aging. It can be caused by loss of outer hair cells, loss of neurons in the cochlea,
atrophy of stria vascularis, impaired mobility of the cochlear partition, and more. So here
is a graph showing that with increased age, there can be increased hearing loss. Symptoms associated with inner ear disorders
are tinnitus, which can be ringing, roaring, or hissing sounds; or recruitment, which is
a significant increase in the perceived loudness when in actuality there is a small increase
in intensity of sound. So there are treatments and procedures for
inner ear disorders, and audiologists can use tests to determine hearing acuity. Audiometry
is a test using an audiometer to measure hearing. Otoscopy uses an otoscope to view the inside
of the ear. There are medications to help with symptoms of inner ear disorders – for
example, motion sickness medications can help with vertigo symptoms. There are also hearing
aids, which amplify sounds at certain frequencies, but they must be fitted by an audiologist.
There’s also a procedure called labyrithectomy, which is an excision of the entire inner ear.
It is done for patients with anacusis, meaning total hearing loss. Here are some references, and thank you for
listening!

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