The latest national neurology data landed with a familiar alarm: more than half of Americans are now living with at least one condition that affects the nervous system.
That figure comes from a sweeping analysis published in JAMA Neurology using Global Burden of Disease 2021 data. The headline number is stark: 180.3 million Americans, or 54.2% of the population, were affected by at least one neurological condition in 2021.
But the most important signal in the data is not scale.
It’s shape.
When researchers looked beyond diagnoses and focused on disability-adjusted life years, a measure that captures both survival and functional health, a clear pattern emerged.
Since 1990:
• Age-standardized prevalence of neurological conditions has stayed essentially flat (down ~0.2%)
• Deaths attributable to neurological disease fell by ~14.6%
• Years lived with disability increased by nearly 10%
Deaths are down. Disability is up.
That combination tells a very specific story.
We are keeping people alive longer while allowing more years of impaired function to accumulate.
This is not a picture of brains suddenly breaking.
It is a picture of brains drifting.
The list of the most common neurological conditions makes this even clearer.
They are not the catastrophic diseases people typically associate with brain decline.
The most prevalent neurological conditions in the U.S. are:
• Tension-type headache (~122 million people)
• Migraine (~58 million)
• Diabetic neuropathy (~17 million)
These conditions are not rare.
They are not abstract.
They interfere with perception, movement, and daily function.
They begin earlier in life.
They last longer.
And they are easy to normalize and easy to miss.
Even when researchers ranked conditions by total disability burden, the picture remained mixed. Stroke and Alzheimer’s disease contribute heavily, but so do migraine and diabetic neuropathy.
The national burden of neurological disease is not driven solely by sudden catastrophic events.
It is driven by long-term functional erosion.
That erosion shows up first in the senses.
Medicine is excellent at identifying disease once it crosses a threshold. Imaging, cognitive tests, and diagnostic criteria all matter. But they operate downstream.
They ask: Is something wrong right now?
Brains, meanwhile, express change continuously.
Not in words. Not in scores. But through perception.
Smell becomes duller.
Vision loses contrast.
Hearing becomes effortful in noisy rooms.
Taste flattens.
Balance requires more attention.
None of this feels like a neurological condition.
It feels like life.
Functionally, though, these changes matter.
The senses are not peripherals to the brain.
They are how the brain receives information from the world.
When sensory input degrades, the brain compensates.
Compensation requires effort.
Over time, that effort shows up as fatigue, withdrawal, slower processing, and reduced resilience.
By the time memory becomes the complaint, the drift has often been underway for years.
This is why moderate change is so dangerous.
Severe impairment gets attention.
Mild change is easy to dismiss.
Moderate decline is where people adapt instead of act.
They turn the volume up.
They avoid restaurants.
They stop driving at night.
They add more salt.
They blame lighting.
They withdraw from conversation.
They move less.
Clinically, these changes often fall below diagnostic thresholds.
Functionally, they increase cognitive load every single day.
Large population studies support this gradient effect.
A 2025 BMC Geriatrics cohort study explicitly modeled severity rather than simple presence or absence of impairment. Mortality risk rose stepwise with combined sensory impairment, and the authors estimated that more than 10% of deaths in the cohort were attributable to these impairments.
Other research shows the same pattern across individual senses.
Olfactory dysfunction alone has been associated with increased mortality risk in nationally representative U.S. samples. Reviews in JAMA Otolaryngology report that:
• Objective smell impairment affects ~20–25% of adults overall
• Exceeds 50% by ages 65–80
• Approaches 80% over age 80
Multi-sensory impairment across smell, taste, hearing, vision, and touch has been linked to higher risk of cognitive dysfunction, physical decline, weight loss, and death within five years.
These are not niche signals.
They are common. They compound. And they are rarely measured together or over time.
Most brain health tools are snapshots.
A cognitive screen shows how you perform today.
Imaging shows structure once there is concern.
A diagnosis tells you whether you crossed a line.
Drift requires a different question:
How is this person changing over time, relative to themselves?
That is a measurement problem, not a screening problem.
A single session establishes a baseline.
Repeating that measurement annually reveals direction.
Direction reveals pattern.
Pattern becomes a durable record that remains meaningful across years, across care settings, and across whatever interventions come next.
This is the prevention window implied by the national neurology data but largely missing from current care.
If years lived with disability are rising even as deaths fall, the lever is earlier functional visibility, before disability becomes the lived reality.
For senior living, this means moving from episodic check-ins to infrastructure that captures gradual change without alarms or medicalization.
For employee wellness, it means recognizing that sensory drift affects safety, fatigue, engagement, and productivity long before claims appear.
For oncology and chronic disease care, it means noticing treatment-related sensory changes early, when adjustments are still easy.
For individuals and families, it means gaining agency without fear, by seeing change while choices are still available.
The national neurology data are being framed as a crisis of disease.
They are better understood as a lag in measurement.
Deaths are down.
Disability is up.
That is drift.
The brain doesn’t break. It drifts.
And drift is most visible through the senses: smell, taste, hearing, vision, and touch.
Tracking all five senses is the new standard.