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