Why Do I Have Tinnitus If My Hearing Test Is Normal?

I got my audiogram at 34 and the audiologist said “within normal limits” before I had my coat off. I took the printout home and looked at it the way I look at a frequency plot, which is the only way I know how to read anything with Hz on the bottom axis.

There was a dip of about 10 dB at 4 kHz, in both ears. It was inside the shaded band that counts as normal, so nobody had reason to mention it.

That is not a story about a bad audiologist. It is a story about what the test is built to do.

What does a standard hearing test actually check?

A pure tone audiogram plays a tone at one frequency, at decreasing volumes, until you stop hearing it. That threshold gets plotted. Then it moves to the next frequency and repeats.

The frequencies it visits are usually 250, 500, 1000, 2000, 4000 and 8000 Hz. Sometimes it adds 3000 and 6000.

Look at that list as a sampling rate and the problem gets obvious. Between 4000 and 8000 Hz there is one test point, and an octave of hearing in between with nothing measured. If you have a narrow notch sitting at 5500 Hz, the test steps right over it.

The other limit is the ceiling. Human hearing runs to about 20 kHz when you are young. The test usually stops at 8.

What did the 2019 study find when it looked more closely?

In 2019, researchers tested 106 people who had tinnitus and a normal standard audiogram. Instead of octave steps, they used a resolution of 1/24 of an octave, and they concentrated it around each person’s tinnitus frequency.

Forty-nine percent of them, 52 out of 106, turned out to have a sharply notched hearing loss. Most of those notches sat at the frequency of their own tinnitus.

Same ears. Same people. A finer ruler.

That result does not mean half of everyone with tinnitus has a hidden notch, because these were people who already had tinnitus and had come to a clinic. What it does mean is that a normal standard audiogram is weaker evidence of intact hearing than it looks.

Is hidden hearing loss the explanation?

There is a second explanation that gets used a lot online, and it deserves a more careful treatment than it usually gets.

The idea is called hidden hearing loss, or cochlear synaptopathy. The proposal is that the connections between the inner hair cells and the auditory nerve can be damaged while the hair cells themselves keep working well enough to pass a threshold test. You would hear the quiet beep in the booth and still have a degraded signal going up the nerve.

In 2011, Schaette and McAlpine found physiological support for it: in people with tinnitus and normal audiograms, the first wave of the auditory brainstem response, the one generated by the auditory nerve itself, was reduced, while a later wave generated further up was normal. That pattern fits a cochlea sending less than it should.

In 2017, Guest and colleagues looked for the same thing in people with tinnitus and normal audiograms, and did not find it. Their conclusion was that the tinnitus related to noise exposure history, but that they saw no evidence of synaptopathy.

Both are real studies in real journals. They disagree.

I am not going to resolve that for you, and anyone who tells you it is settled is overselling. What I take from it is narrower and still useful: there is more than one way to have a normal audiogram and a loud ear, and the profession is still arguing about which ones matter most.

So is a normal hearing test useless?

A normal audiogram is not meaningless and it is not a mistake. It rules out the degree of hearing loss that would change your immediate care, and that is worth knowing.

It also does not mean you should go hunting for a diagnosis on your own. The gap between “the standard test has limits” and “therefore I know what I have” is enormous, and most of what fills that gap online is being sold to you.

What can I ask for at my next hearing test?

• Ask whether high frequency audiometry is available. Testing above 8 kHz is not standard, but it exists, and it is where some of the missed loss lives.
• Ask about finer frequency steps around your tinnitus pitch, rather than only the standard octaves. That is exactly what the 2019 study did to find those notches.
• Bring your own observations. If the sound changes when you move your jaw or turn your head, say so, because that points at a different mechanism entirely.
• Keep the printout. Not to diagnose yourself, but because a second reading later is easier when you have the first one.

FAQ

Can a hearing test detect tinnitus?

Not directly. A standard hearing test measures the quietest tones you can hear. It does not measure the sound you are hearing. Some clinics also match the pitch and loudness of the tinnitus, and what the test can show is whether there is a measurable hearing loss alongside it.

Will it go away if my hearing test is normal?

A normal test does not predict it either way. For some people tinnitus fades, particularly soon after it starts, and nobody can predict an individual case.

Does a normal hearing test mean my tinnitus is psychological?

No. It means the standard test did not find a threshold shift at the points it sampled, which is also what a clean ENT exam means and does not mean. Those are different statements, and the second one does not imply the first.

Should I ask for a retest?

Repeating the same test usually gives you the same information. Asking for a different test, higher frequencies or finer steps, is the more useful request, and what the chart does and does not cover is worth reading before you book it.

Is hidden hearing loss a real diagnosis I can be given?

Not as a clinical diagnosis you will see on paperwork. It is a research idea with support on one side and contradiction on the other, and there is no routine clinical test for it.

If the notch is at my tinnitus frequency, does treating it help?

Nobody has shown that. Finding a notch explains something about where the sound may come from; it does not come with a way to reverse it.

Can my hearing be normal now and get worse later?

Hearing can change over time, which is why a baseline is worth keeping. That is a reason to protect your ears, not a prediction about your tinnitus.

Sources

1. Xiong B, Liu Z, Liu Q, Peng Y, et al. Missed hearing loss in tinnitus patients with normal audiograms. Hearing Research, 2019 Dec;384:107826.
2. Schaette R, McAlpine D. Tinnitus with a normal audiogram: physiological evidence for hidden hearing loss and computational model. Journal of Neuroscience, 2011 Sep 21;31(38):13452-7.
3. Guest H, Munro KJ, Prendergast G, et al. Tinnitus with a normal audiogram: Relation to noise exposure but no evidence for cochlear synaptopathy. Hearing Research, 2017 Feb;344:265-274.