Presbycusis is age-related hearing loss that results from damage to hair cells in the cochlea and other structures in the inner ear. It can be caused by genetic factors, noise exposure, certain medications, and the natural aging process. The author's grandfather suffers from presbycusis, which was likely genetic, and now experiences difficulty understanding speech and distinguishing sounds. His presbycusis has led to depression due to resulting communication challenges. The author has developed greater empathy for their grandfather and elderly people in general after learning about the impact of presbycusis through this course.

1. Presbycusis
By Adriana Youman N

2. What is it?
Presbycusis refers to bilateral age-related hearing loss. In
literal terms, presbycusis means "old hearing" or "elder
hearing." (1)
This is due to the release of free radicals in cellular
metabolism leading to cell death of cochlear hair cells, stria
vascularis, and sensorineural degeneration. It also leads to
vasoconstriction of end arteries resulting in hypoxia,
ischemia, and necrosis of cells. (2)

3. Etiology:
There are many factors that originate presbycusis, some of the most common
ones are:
1. Age- related factors: this are factors that are common in the final stages of
humans development, basically in the elderly.
2. Genetic factors: specifically differences in mitochondrial DNA expressive
genes related to oxidative stress have been found in patients with this
disease. (1)
3. Ototoxic factors: there are multiple medications associated with ototoxicity
(salicylates, loop diuretics, aminoglycoside). (2)

4. 4. Noise Exposure factors: some studies have shown that some
individuals who have suffered noise- induced cochlear damage in
their youth develop more severe presbycusis. (1)
5. Hormonal factors: Glucocorticoids, sex hormones, and
glutamate signaling are thought to play a role in presbycusis. (3)

5. Types:
- There are 6 different categories of presbycusis: (1)
1. Sensory: loss of receptor hair cells at the basal aspect of the cochlea
resulting in characteristic high-frequency hearing loss.
2. Neural: loss of cochlear nerve fibers as well as the loss of spiral ganglion
neurons.
3. Strial/ metabolic: degeneration of stria vascularis cells. These cells are
essential for maintaining the appropriate ion composition of endolymph to
generate the endocochlear potential for signal transduction.

6. 4. Mechanical (cochlear conductive): due to physical changes of the cochlear
duct. This is accompanied by a specific audiogram pattern.
5. Mixed: characterized by pathologic changes in more than one of the above
structures.
6. Indeterminate: cases in which changes to the above structures are not
significant.

7. Parts of the nervous system and how are they
affected:
- The cochlea: that is a spiral-shaped structure in the inner ear responsible
for converting sound vibrations into electrical signals that can be
interpreted by the brain. In some cases of presbycusis, the hair cells
within the cochlea, which are responsible for detecting sound vibrations,
can become damaged or degenerate, leading to reduced hearing
sensitivity.

8. - Auditory nerve: also known as the cochlear nerve, carries the electrical
signals generated by the hair cells in the cochlea to the brainstem. With
presbycusis, the number of auditory nerve fibers may decrease, and their
function can be compromised, leading to difficulties in transmitting auditory
information to the brain.
- Central Auditory Pathways: the auditory nerve fibers transmit signals to
various auditory nuclei in the brainstem and then to higher auditory
processing centers in the brain, such as the inferior colliculus and the
auditory cortex. In presbycusis, the efficiency of these neural pathways can
be reduced, leading to difficulties in processing and interpreting complex
sounds.

9. - Auditory Cortex: The auditory cortex is a region of the brain responsible for
processing sound information and interpreting it as meaningful sounds. In
presbycusis, the reduced input from the damaged cochlea and auditory nerve
can lead to changes in the functioning of the auditory cortex, affecting the
brain's ability to process and understand sound.

10. My case:
My grandfather sufferers from presbycusis, his father also had it so he always
had a genetic predisposition to develop it in his elder years. My grandfather
shows the following symptoms:
- When people talk to him, he says their voices sound slurred, therefore
conversations are really difficult to understand and that really frustrates him.
- When there is background noise he can not really distinguish where are
sounds coming from and some sounds sound too loud and that annoys him a
lot.

11. Comorbidity:
Comorbidity is fairly common with presbycusis, many other diseases
can cause it, it my grandfather´s case it has been presbycusis what
caused a comorbid disorder, his personality has changed a lot
through the years, he feels outraged quite often and he always
expresses feelings of frustration, he says that he can not see
meaning in life if he can't even understand conversations and he
doesn't even enjoy others company anymore, so he has been
diagnosed with depression.

12. Comorbidity- Depression:
Depression (major depressive disorder) is a common and serious
medical illness that negatively affects how you people feel and the
way they think and act, it causes feelings of sadness and/or a loss
of interest in activities you once enjoyed. (4)
- Up to 1 in 5 older adults with hearing loss report a clinically
relevant level of depression symptoms that would necessitate
treatment, and a further 22% experience the onset of incident
depression symptoms over time.(5)

13. How this course changed my view of the elderly
people:
- Before taking this course I'm not really proud to admit that I saw my
grandfather as a cranky old man, he was bothered by kids playing, people
laughing, parties, etc. I remember that as soon as week 5 started, in the
second video: “Experiences of Hearing Loss”, I immediately thought of him, I
thought it wouldn't be a pleasant experience to learn about how much people
can suffer and all the ways their life can be affected by such a common
disease. But, I was surprised to find myself feeling more and more empathy
towards my grandfather as the week went on.

14. Now I think that it was my favorite topic to learn about, I was really interested in
learning more of the treatments available, I now talk with my grandfather all the
time and I always tell him the new things I learn, and I'm really grateful for that,
plus I think I have developed some ideas of a possible treatment for presbycusis
in the future.
So in conclusion, I now think that most of the times humans don't like each other
because they don't really understand what the other is going through, the more
you understand how others may be experiencing life, the more easy it is for you
to feel empathy towards them and a real deep necessity of helping in any way you
can, that has been a possibility for me since learning some new things in this
course.

15. References:
1. Cheslock M & De Jesus O. Presbycusis. StatPearls. 2020 July 10
;32644646.
2. Kumar T. Presbycusis. Indian Journal of Otology. 27(3):p 121-123, Jul–Sep
2021.
3. Hisim R. Age- Related Hearing Loss. John Hopkins Medicine . 2023.
4. Torres F. Depression. American Psychiatric Association. October 2020.
5. Suzanne Cosh, Catherine Helmer, Cecile Delcourt, Tamara G Robins &
Phillip J Tully (2019). Depression in elderly patients with hearing loss:
current perspectives, 1471-1480, DOI: 10.2147/CIA.S195824