A sudden sensation of numbness? The nagging headache that just won't quit? That weird weakness in your leg? They're all symptoms of neurological disorders - a family of conditions that affects more than half of the U.S. population, according to a new Yale study.
And because these symptoms are often harbingers of health problems that are far more serious, researchers say they require a boost in public awareness.
"People blow off warning signs," said study author John Ney, an assistant professor of neurology at Yale School of Medicine. "I've had plenty of patients who experience a sudden onset of weakness or numbness down one side of the body, and say, 'Well, this will probably go away. I'm going to go to bed and hope it'll be gone the next day.' And they wake up with a long-term disability, because they had a stroke that should have been addressed much earlier."
The new study, published in the journal JAMA Neurology, revealed that about 180.3 million people in the U.S. (more than half of the population of roughly 332.7 million) are affected by disorders affecting nervous system health. Indeed, among that group these disorders were the leading cause of disability. Conditions posing the greatest risk of disability were stroke, Alzheimer's disease and other dementias, diabetic neuropathy, and migraine.
The results were based on data from the broader Global Burden of Disease 2021, which collected data from 1990 to 2021. (In addition to Ney, researchers from the University of Washington; Emory University; and the American Academy of Neurology took part in the study.)
In a Q&A, Ney discussed the prevalence of neurological disorders, what might be driving their spike, and why the United States needs to pour more resources into combatting these conditions.
What are some of the neurological disorders included in the study?
John Ney: Epilepsy, multiple sclerosis, stroke, and Alzheimer's disease are all included in the current study. But we used a broader lens to parse this data, and we looked at other diseases that cause damage to the nervous system. So not just "neurological" diseases, but conditions like diabetes that cause substantial morbidity through neuropathy and other nervous system injury. There's also a focus on neurodevelopmental disorders like autism and cerebral palsy, as well as idiopathic intellectual disabilities.
Were any of the findings surprising to you?
Ney: One of the biggest findings is the overall prevalence of neurological disorders. So, 54% of the American population has a disorder that affects the nervous system. It doesn't have to be one of the traditional neurological disorders. It may be neurological damage sustained from other disease processes, including diabetes. Globally, the prevalence rate was 43%, but the U.S. rate is actually higher. The United States has the highest prevalence of diseases affecting the nervous system of any country, whether high-income, low-income or middle-income.
