Your Senses & Your Brain: How Hearing, Vision, and Smell Connect to Brain Health

We don't normally consider our senses when we think about brain health. But your brain is constantly receiving and interpreting sensory information from the world around you.

Research is uncovering important connections between changes in our senses and cognitive and neurological health.

Some sensory changes may represent modifiable risk factors we can address. Others may provide an early clue that something is changing in the nervous system.

Understanding these connections gives us another way to think about supporting lifelong brain health.

What Research Shows About Senses and Brain Health

Hearing: More Than Just Your Ears

Hearing loss has consistently been associated with cognitive decline and dementia risk. The 2024 Lancet Commission continues to identify hearing loss as an important potentially modifiable dementia risk factor.

Researchers believe several factors may contribute. When hearing becomes more difficult, the brain has to work harder to interpret speech. Hearing difficulties can also make conversations and social activities more challenging, potentially contributing to social isolation. Brain-imaging research has also associated hearing loss with brain atrophy in areas involved in auditory processing and cognition. 

The degree of hearing loss also matters, with greater hearing impairment generally associated with greater cognitive risk.

One of the most important studies in this area is the ACHIEVE trial, which examined whether treating hearing loss could help slow cognitive decline.

Across the full study population, hearing intervention did not significantly slow cognitive decline. However, among older adults who entered the study at greater risk for cognitive decline, hearing intervention was associated with a 48% slower rate of cognitive decline over three years.

Hearing deserves a place in the brain-health conversation, and hearing changes shouldn't automatically be dismissed as "just getting older." Hearing loss gives us something important to pay attention to—and, in many cases, something we can address.

Vision: Another Overlooked Connection

Uncorrected vision loss has also been associated with cognitive decline and dementia.

The connection is significant enough that the 2024 Lancet Commission added untreated vision loss to its list of potentially modifiable dementia risk factors.

Why might vision matter?

Vision problems can affect reading, driving, physical activity, independence, mental stimulation, and social interaction. Some of the same vascular and metabolic conditions that affect the eyes may also affect the brain.

The encouraging part is that some causes of vision impairment are preventable or treatable.

Regular eye care may therefore support much more than simply seeing clearly. Identifying and addressing vision problems can also help people remain active, independent, and engaged with the world around them.

Smell: An Early Neurological Clue?

Smell is different from hearing and vision.

Rather than viewing reduced smell primarily as something that causes cognitive or neurological problems, researchers are interested in it as a possible early marker of changes occurring in the nervous system.

Reduced sense of smell is particularly well recognized in Parkinson's disease. It is a common early feature and can appear years or even decades before a Parkinson's diagnosis.

Smell dysfunction has also been studied as an early feature of other neurodegenerative diseases, including Alzheimer's disease. Scientists are investigating how changes in the olfactory system may relate to the abnormal protein accumulation and neurological changes associated with these diseases, but the underlying mechanisms are still not fully understood.

Losing your sense of smell does not mean you have or will develop Parkinson's disease, Alzheimer's disease, or another neurodegenerative condition.

Smell can change for many reasons, including:

• Aging

• Respiratory infections

• Sinus problems

• Certain medications

• Smoking

• Head injury

• Other medical conditions

Still, a persistent or unexplained change in smell is worth paying attention to rather than automatically ignoring.

Why It Matters

Your senses help keep your brain connected to the world around you.

They influence communication, movement, independence, nutrition, social connection, and the amount of sensory information your brain receives every day.

Hearing and vision are particularly important because some causes of sensory impairment can be identified and addressed. Smell is somewhat different—it may occasionally provide an early clue that something deserves further attention.

Supporting sensory health is therefore another piece of supporting lifelong brain health.

And sometimes the simplest first step is simply noticing when something has changed.

Five Practical Takeaways

1. Don't ignore hearing changes.

Frequently asking people to repeat themselves, turning up the television, or struggling to understand conversations in noisy environments may be signs that it's worth having your hearing evaluated.

2. Keep up with routine eye care.

Vision changes aren't always obvious, and some treatable eye conditions can progress gradually. Regular eye examinations can help identify changes earlier.

3. Pay attention to your sense of smell.

A persistent or unexplained change in smell is worth discussing with your healthcare provider, particularly if you are also experiencing other new neurological symptoms.

4. Protect the senses you have.

Use appropriate hearing protection around loud noise, protect your eyes from excessive UV exposure, and follow recommended preventive hearing and eye care.

5. Stay socially and mentally engaged.

Hearing or vision changes can sometimes make conversations, hobbies, reading, driving, or social activities more difficult.

Rather than simply withdrawing from those activities, addressing sensory limitations may make it easier to remain active and connected.

🌿 Rooted Habit: Do a Sensory Check-In

Take a minute and ask yourself:

Hearing: Am I turning things up louder or asking people to repeat themselves more often?

Vision: Have I noticed changes in my vision—or am I overdue for an eye exam?

Smell: Has my ability to smell changed noticeably without an obvious explanation?

If you notice a persistent or meaningful change, consider discussing it with an appropriate healthcare professional.

The goal isn't to worry about every small change.

It's simply to notice rather than ignore what your senses may be telling you.

Supporting Your Sensory & Brain Health

Sensory health is only one part of the bigger picture.

Many of the same foundations that support overall brain health remain important:

• Regular physical activity

• Nutrient-dense foods

• Healthy blood sugar and cardiovascular health

• Restorative sleep

• Social connection

• Mental stimulation

Brain health rarely comes down to one intervention. It is the accumulation of many small choices over time.

🌿 Continue Exploring Brain Health

Explore more evidence-based education in the Brain Health Education Library, including topics related to:

• Memory & Cognition

• Healthy Aging & Longevity

• Parkinson's Disease

• Nutrition for Brain Health

• Exercise & Movement

• Sleep & Brain Health

You can also subscribe to The Weekly Brain Health Brief for practical brain-health education and one simple Rooted Habit delivered each week.

References

The Lancet Commission on dementia prevention, intervention and care (2024). Hearing loss and untreated vision loss are among the potentially modifiable risk factors identified in the Commission's updated dementia-prevention framework.

ACHIEVE Trial. A randomized clinical trial examining hearing intervention and cognitive decline in older adults. The overall trial did not demonstrate a significant cognitive benefit across all participants, while participants at increased risk for cognitive decline experienced a 48% slower rate of decline over three years.

Parkinson's Foundation. Reduced sense of smell is a common early feature of Parkinson's disease and may occur years or decades before diagnosis.

Olfaction and neurodegenerative disease review. Smell dysfunction is being investigated as a potential early marker of neurodegenerative diseases including Parkinson's and Alzheimer's disease, although the underlying mechanisms remain incompletely understood.

This information is provided for educational purposes and is not intended to diagnose, treat, or replace individualized medical care.