Ear infections and auditory sensitivity

Have you ever been curious about why so many adults with ADHD have a history of ear infections? Could the two be related? Could this be a factor of auditory processing?

How Infections Can Alter the Brain’s Noise Filtering

Most people think of ear infections as short-term nuisances: painful, inconvenient, but ultimately harmless once the swelling subsides. The truth is more complex. Repeated or severe infections can leave behind subtle but important changes at the cellular level. These changes may not cause hearing loss in the traditional sense, but instead they disrupt the brain’s ability to separate meaningful sounds from background noise. The result: frustration, overwhelm, and difficulty focusing in noisy environments.

The Ear is a Biological Signal Processor

The auditory system is a finely tuned communications network. Sound waves enter the outer ear and vibrate the tympanic membrane (eardrum). These vibrations pass through the ossicles (tiny bones in the middle ear) and into the cochlea of the inner ear, where specialized cells called inner and outer hair cells transduces vibration into electrical signals.

From an engineering perspective, this process is similar to converting an analog signal into a digital one. The hair cells act as transducers, preserving both the strength and clarity of the original input. When this first stage works well, the “signal-to-noise ratio” is high—the brain receives a clean, precise signal to interpret.

What happens with an ear infection:

Middle ear infections (otitis media) and inner ear infections (labyrinthitis) can cause inflammation, fluid buildup, and in some cases direct cellular damage. Repeated infections can:

• Damage hair cells in the cochlea, reducing their ability to amplify and sharpen sound input.

• Disrupt synaptic transmission between hair cells and auditory nerve fibers, weakening the fidelity of the signal sent to the brain.

• Cause demyelination or reduced conduction efficiency along the auditory nerve, slowing transmission and increasing variability.

Each of these changes lowers the signal-to-noise ratio. The signal gets harder to identify and the noise is what’s noticed. This causes the brain more difficulty in separating out room/environmental noise from what you are trying to listen to.

If the signal arriving from the cochlea is already degraded, then each subsequent stage, brainstem nuclei, midbrain (inferior colliculus), thalamus (medial geniculate body), and auditory cortex, is working with compromised input. Just as a blurry photo remains blurry no matter how much you adjust the brightness, a degraded sound signal cannot be fully “cleaned up” or reconstructed by the brain.

The result:

• Difficulty filtering background noise.

• Increased listening effort and cognitive load.

• A persistent sense of frustration in noisy environments.

Why This Matters

For children, these subtle auditory processing issues can manifest as trouble learning in classrooms. For adults, it may appear as difficulty following conversations in restaurants, chronic fatigue from listening effort, or irritability in group settings. Importantly, this is not just about “hearing loss” measured on a standard audiogram—it is about auditory processing efficiency.

It’s important to recognize that the ear is not just a passive microphone. It is the first stage of a sophisticated biological signal-processing chain. Protecting it, by preventing, treating, and following up on ear infections—means preserving not just hearing, but the ability to engage fully in a crowded and noisy world.