Tinnitus can show up when the hearing test looks normal

The standard test for hearing damage asks one question: what is the quietest sound you can detect at each pitch? If you can hear the quiet tones, the test says your hearing is fine.

Audiometric thresholds and word recognition scores were analyzed for 267,395 Veterans, and among them are people with a constant ringing in their ears and nothing wrong on that test.

The authors think the test is asking the wrong question.

What tinnitus is

Tinnitus is the perception of sound that does not have an external source, so other people cannot hear it. It is commonly described as a ringing sound, but some people hear other types of sounds, such as roaring or buzzing.

It is far more common than most people assume. Tinnitus is common, with surveys estimating that 10 to 25% of adults have it, and when tinnitus lasts for three months or longer, it is considered chronic.

Most of the time it is a nuisance rather than a danger. It is only rarely associated with a serious medical problem and is usually not severe enough to interfere with daily life. But some people find that it affects their mood and their ability to sleep or concentrate, and in severe cases, tinnitus can lead to anxiety or depression.

The link to hearing is the part this study complicates. The causes of tinnitus are unclear, but most people who have it have some degree of hearing loss.

Why veterans

Because the exposure is unmistakable and the records exist.

Tinnitus is the most common service-related disability among veterans because of loud noise they may have experienced from gunfire, machinery, bomb blasts, or other similar sources. Nobody has to reconstruct whether these people were exposed to damaging sound.

They are also tested. The Million Veteran Program links a research cohort to decades of clinical measurements, which is how a study reaches a quarter of a million people with real audiology data rather than survey answers.

The scale of ordinary hearing loss makes this worth reading beyond the military. Approximately 15% of American adults ages 18 and over report some trouble hearing, and about one in three people in the U.S. between the ages of 65 and 74 has hearing loss. Nearly half of those older than 75 have difficulty hearing.

What the veterans’ hearing tests showed

Among 267,395 Veterans, 94% male, 86% had hearing loss and 47% reported tinnitus.

Read that number carefully, because it is not the veteran rate. These are veterans who use Veterans Affairs health care and who had a hearing test on file, and people generally get a hearing test because something prompted one. The authors are explicit about who this describes: hearing loss and tinnitus are highly prevalent among VA healthcare-using Veterans.

The comparison with civilians is where the noise exposure shows. Compared with the civilian cohort, Veterans showed earlier and greater hearing loss, particularly at 4 kHz. That is a high-pitched region, the classic signature of noise damage rather than aging.

The civilian group is itself worth a caveat, and the authors flag it by calling the comparison descriptive. It was 40,912 adults from a clinical cohort at Massachusetts Eye and Ear: people who had gone to a specialist ear hospital. Two selected groups are being compared, and neither is the public.

Men and women differed in pattern rather than amount. Men showed greater high-frequency loss, whereas women showed steeper low-frequency declines at older ages, though with 94% of the cohort male, the female half of that comparison rests on a much smaller group.

The finding about normal hearing tests

Here is the part that should change how a reader interprets their own results.

The authors describe the occurrence of tinnitus in some individuals with preserved audiometric thresholds and subtle suprathreshold deficits. Preserved thresholds means the quiet-tone test was normal. Suprathreshold means what happens at ordinary listening volumes, which that test never examines.

Their explanation is that these patterns are consistent with mechanisms such as cochlear nerve degeneration that are not captured by conventional audiometry. The nerve fibers carrying sound from the ear to the brain can be lost while the cells that detect the faintest tones survive, so the booth test passes and real hearing does not.

There is supporting evidence in the word recognition scores. Because Veterans with tinnitus were younger for a given degree of hearing loss, word recognition scores were similar between groups when adjusting for hearing thresholds alone; however, after accounting for age, Veterans with tinnitus showed slightly poorer word recognition.

Slightly poorer is a small effect. Its importance is not its size but its existence: a difference that only appears once you look past the threshold test is a difference the threshold test cannot see.

What tinnitus traveled with

The pattern of associations is consistent with an injury story rather than a purely ear-based one.

Tinnitus prevalence was higher among Veterans with traumatic brain injury or concussion and among those reporting anxiety or depression, with smaller increases associated with sleep disturbance and alcohol use.

The mental health link should be read in both directions, and this study cannot separate them. Tinnitus can lead to anxiety or depression in severe cases; distress also makes an intrusive sound more noticeable; and a blast injury can produce all of it at once.

One association was absent. Tobacco use showed no association with tinnitus prevalence, which is worth noting because smoking gets attached to most long lists of health risks.

What this hearing study cannot show

Everyone was measured once. That single fact bounds the whole paper: it can describe who has what, and it cannot say what came first or how anything progressed.

The population is 94% male, mostly older, and self-selected into a health system through having a problem. Applying 86% to any general population would be a serious error.

The cochlear nerve explanation is an interpretation, not a measurement. The authors are proposing a mechanism consistent with their pattern; establishing it would require measurements this study did not make.

And the paper is paywalled, so the authors’ own limitations section was not available for this piece.

What to take from it if your ears ring

The first thing is that a normal hearing test is not a clean bill of health for your ears. If you have persistent ringing and were told your hearing is fine, this study says that combination is real and recognized rather than imagined.

The second is that there is something to do about the symptom even without a cure. There is no cure for tinnitus, but there are ways to reduce symptoms, and common approaches include the use of sound therapy devices (including hearing aids), behavioral therapies, and medications.

The third is prevention, which is the only part anyone fully controls. Scientists don’t yet know how to prevent age-related hearing loss, but you can protect yourself from noise-induced hearing loss. The advice is unglamorous and it works: avoid loud noises, reduce the amount of time you’re exposed to loud sounds, and protect your ears with earplugs or protective earmuffs.

The list of things worth protecting against is more domestic than most people expect. Potential sources of damaging noises include loud music, headphones and earbuds used at high volume, construction equipment, fireworks, guns, lawn mowers, leaf blowers, and motorcycles.

A quarter of a million veterans is a very large demonstration of what happens when nobody does that.

Audio is marketed well beyond hearing care, and the evidence thins out quickly once you leave it. Trials of binaural beats are a case in point.