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What’s that ringing in your ears? - Marc Fagelson - Video học tiếng Anh
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What’s that ringing in your ears? - Marc Fagelson
What’s that ringing in your ears? - Marc Fagelson
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0:07
Arriving home after a long day, you settle in for a quiet evening alone.
0:12
But instead of the sound of silence, you hear a constant ringing—
0:17
even though there’s nothing making any noise.
0:20
What you’re experiencing is called tinnitus,
0:23
the perception of a noise like ringing, buzzing, hissing or clicking
0:28
that occurs without any external source of sound.
0:32
Tinnitus has been bothering humanity since Ancient Babylon,
0:36
plaguing everyone from Leonardo da Vinci to Charles Darwin.
0:41
Today, roughly one in seven people worldwide
0:44
experiences this auditory sensation.
0:47
So where does this persistent sound come from?
0:51
When you normally hear something, sound waves hit various areas of your ear,
0:56
creating vibrations that displace fluid inside the cochlea.
1:02
If the vibrations are large enough,
1:04
they elicit a chemical response that transforms them
1:07
into bioelectrical signals.
1:10
These nerve impulses are then relayed through the hearing pathway to the brain,
1:15
where they result in the sounds we perceive.
1:18
However, in the vast majority of tinnitus cases,
1:22
the nerve signals that produce these mysterious sounds
1:25
don’t travel through your ear at all.
1:28
Instead, they’re generated internally, by your own central nervous system.
1:34
Under usual circumstances, these self-produced signals
1:38
are an essential part of hearing.
1:40
All mammals demonstrate on-going neural activity
1:44
throughout their hearing pathways.
1:46
When there are no sounds present,
1:48
this activity is at a baseline that establishes your neural code
1:53
for silence.
1:54
When a sound does appear, this activity changes,
1:58
allowing the brain to distinguish between silence and sound.
2:03
But the auditory system’s health can affect this background signal.
2:08
Loud noises, diseases, toxins, and even natural aging
2:13
can damage your cochlear cells.
2:16
Some of these may heal in a matter of hours.
2:19
However, if enough cells die, either over time or all at once,
2:25
the auditory system becomes less sensitive.
2:29
With fewer cochlear cells relaying information,
2:32
incoming sounds generate weaker nerve signals.
2:35
And many environmental sounds can be lost completely.
2:39
To compensate, your brain devotes more energy to monitoring the hearing pathway.
2:45
Just like you might adjust the knobs of a radio,
2:48
the brain modifies neural activity while also tweaking the tuning knob
2:53
to get a clearer signal.
2:56
Increasing this background neural activity is intended to help you process
3:00
weak auditory inputs.
3:04
But it can also modify your baseline for silence—
3:07
such that a lack of sound no longer sounds silent at all.
3:12
This is called subjective tinnitus,
3:15
and it accounts for the vast majority of tinnitus cases.
3:19
Subjective tinnitus is a symptom associated with
3:22
practically every known ear disorder,
3:25
but it isn’t necessarily a bad thing.
3:28
While its appearance can be surprising,
3:30
subjective tinnitus has no inherently negative consequences.
3:34
But for some, tinnitus episodes can trigger traumatic memories
3:39
or otherwise distressing feelings,
3:42
which increase the sound’s intrusiveness.
3:45
This psychological loop often leads to what’s known as “bothersome tinnitus,"
3:50
a condition that can exacerbate the symptoms of PTSD, insomnia,
3:55
anxiety, and depression.
3:58
There’s no known cure for subjective tinnitus.
4:01
So the most important thing doctors can do
4:04
is help people understand this auditory event,
4:07
and develop neutral associations with these often-distressing sounds.
4:12
For example, sound therapy uses noises like rain, birdsong, or music
4:19
to mask tinnitus and reduce stress.
4:22
One form, called informational masking, uses soothing, complex auditory signals
4:28
that distract the brain from the tinnitus sound.
4:32
Another, called energetic masking,
4:34
uses sounds with the same frequency as the patient’s tinnitus
4:38
to occupy the neurons that would otherwise deliver the tinnitus signal.
4:43
Practiced alongside counseling,
4:45
these interventions allow people to re-evaluate
4:49
their relationship with tinnitus.
4:52
Losing the sound of silence can be troubling to say the least.
4:56
Tinnitus reveals that your brain is constantly analyzing the world around you,
5:01
even as it fails to filter its own internal noise.
5:05
In a sense, experiencing tinnitus
5:08
is like eavesdropping on your brain talking to itself—
5:11
though it may not be a conversation you want to hear.
