Noise Sensitivity After Concussion: Why Sound Feels Too Loud

Is Noise Sensitivity Normal After a Concussion?

It's one of the more common symptoms. In a New Zealand study that followed 341 adults after a mild traumatic brain injury, 45% reported noise sensitivity within the first 2 weeks (Shepherd, 2021). Among 302 adults seen within a week of a concussion who had headache, 72% had sensitivity to sound with it and 74% had sensitivity to light (Langer, 2022).

It can also be measured. Researchers tested 28 athletes with normal hearing who had a history of concussion. Half of them reported sound sensitivity, and that half had lower loudness discomfort thresholds than the others, meaning sound became uncomfortable for them at a lower volume (Assi, 2018).

Why Does Sound Feel Too Loud?

Our team's way of thinking about any sensory sensitivity is bandwidth. A person with a sensitivity doesn't have the capacity to take on all of that stimulus at once, and it becomes noxious, an irritant. Everyone has a version of this. When kids get wild and loud there's a point where it's too much, and that point comes sooner when you're tired or the day has been long. The threshold for how much noise you can tolerate moves.

The same thing happens after a brain injury, with a lower ceiling. When the computer is damaged the processing speed goes down, the way a phone that's been dropped runs slower and hotter. Less processing speed means less sound can be taken in before it overloads.

Sound sensitivity often travels with light sensitivity. The first areas of the brain that process the 2 sit very close together, almost like 2 halves of a duplex, so whenever our team sees one, we check for the other. Finding both, or only 1, helps show where the system is failing. Light is covered on light sensitivity, and ringing in the ears on tinnitus after a concussion.

How Long Does Noise Sensitivity Last After a Concussion?

For most people it eases over the first year, and 2 good studies disagree on how many it stays with. In the New Zealand cohort, the share reporting noise sensitivity fell from 45% at baseline to 28% at 12 months (Shepherd, 2021). A Dutch study of 186 people with a mild traumatic brain injury and 181 people with an orthopedic injury found more noise and light sensitivity in the brain injury group from 2 weeks to 3 months, only about 3% with sensitivity that persisted through the whole year, and no difference between the groups at 12 months (Marzolla, 2023).

Early noise sensitivity also says something about the road ahead. In the New Zealand study it predicted later post-concussion symptoms (Shepherd, 2021), and a review of 2 studies found that noise sensitivity, vestibular problems and anxiety went together, and that having them was the strongest indicator symptoms would last beyond 3 months (Miller, 2024). Our team reads that as a reason to measure the vestibular system in anyone whose noise sensitivity hasn't eased.

Do Earplugs Help, or Make It Worse?

Earplugs and noise-cancelling headphones feel like relief, and worn all day they may work against you. The hearing system adjusts its own volume. When healthy adults wore an earplug in 1 ear for 7 days, the reflex that responds to loud sound fired at a lower volume in that ear afterward, which the authors took as the brainstem turning its gain up (Munro, 2009). A 2-week version found the same reflex shifting by 8 to 10 decibels, with a modest rise in how loud sounds seemed after the first week (Hutchison, 2023).

Normal sound After earplugs

That research was done in healthy ears, so applying it to concussion is a step our team takes with care. It lines up with what's known about hyperacusis, where raised auditory gain is part of the picture and sound therapy is used to bring it back down by gradual exposure (Henry, 2022).

Long retreats into a dark, quiet room don't help either. In a randomized trial of 88 patients aged 11 to 22, those told to rest strictly for 5 days reported more daily symptoms over the next 10 days than those who rested for 1 to 2 days and then returned to activity step by step (Thomas, 2015). Our team's early rest window after a concussion is 7 to 14 days. Past it, our team's view is that shielding yourself from ordinary sound keeps the threshold low. Earplugs still have a place for sound that's loud enough to bother anyone, such as a concert or power tools.

What Does Our Team Do About Noise Sensitivity?

Treatment starts with finding where the weak spot is. Is it light, is it sound, or both? The pathways behind each are known, so the exam can test them directly. Then the work is building tolerance back up in steps, so that processing gets faster and the brain can take on more information again. Thinking about it that way opens up more options than waiting for it to pass or avoiding sound for good.

Because noise sensitivity clusters with vestibular problems (Miller, 2024), our team looks at balance and eye movements alongside it. What the exam measures is on concussion testing: what to expect.

See a physician or an audiologist if the sensitivity came with a change in your hearing, ear pain, or ringing in 1 ear that's new.

Noise Sensitivity After Concussion: FAQ