Studies seek early signs of dementia
Learning your odds of eventually developing dementia requires medical testing and counseling. But what if everyday behavior, like overlooking a couple of credit card payments or habitually braking while driving, could foretell your risk?
A spate of experiments is underway that reflect growing awareness that the pathologies underlying dementia can begin years or even decades before known symptoms emerge.
“Early detection is key for intervention, at the stage when that would be most effective,” said Sayeh Bayat, the lead author of a driving study funded by the National Institutes of Health and conducted at Washington University in St. Louis.
For now, the search for older people who are likely to develop Alzheimer’s or other dementias takes place mostly in research settings, where patients learn their risk status through some combination of genetic testing, spinal taps or brain scans to detect amyloid in the brain, as well as through questions about family history.
“It’s all about finding people soon enough to intervene and prevent or delay the onset of the disease,” said Emily Largent, a medical ethicist and health policy researcher at the Penn Memory Center in Philadelphia, which undertakes many such studies.
Other kinds of predictive tests are on the horizon, including overthe-counter blood tests for tau protein, another Alzheimer’s biomarker, but these tests are several years away, Largent said.
That leaves methods that are invasive, like spinal taps, or expensive, like PET scans. These approaches can’t be used to screen large groups of people. And “they’re not available everywhere,” Bayat said.
But a GPS device in someone’s car could monitor driving behavior almost continuously at low cost, providing so-called digital biomarkers.
“Studies have shown that driving changes in people with symptomatic Alzheimer’s,” Bayat said. “But some changes occur even earlier.”
The Washington University study enrolled 64 older adults with preclinical Alzheimer’s, as determined by spinal taps (the results were not shared with participants), and 75 who were deemed
cognitively normal.
For a year, researchers measured both groups’ driving performance — how often they accelerated or braked aggressively, exceeded or fell well below the speed limit, made abrupt moves — and their “driving space” (number of trips, average distance, unique destinations, trips at night). “Only now, because we have these technologies, can we do this kind of research,” Bayat said.
The study found that driving behavior and age could predict preclinical Alzheimer’s 88% of the time. Those findings could spur recruitment for clinical trials and allow interventions — like an alert when a car drifts — to help keep drivers on the road. In areas with inadequate public transportation (which is most areas), that could enhance senior citizens’ independence.
Dr. Jason Karlawish, a geriatrician and co-director of the Penn Memory Center, called the study “provocative” and well designed. “The results suggest that monitoring a real-world, cognitively intense behavior can detect the earliest, subtle signs of emerging cognitive impairment,” he said.
SYMPTOMS IN CREDIT REPORTS?
A study analyzing medical records and consumer credit reports for more than 80,000 Medicare beneficiaries showed that senior citizens who eventually received a diagnosis of Alzheimer’s disease were significantly more likely to have delinquent credit card payments than those who were demographically similar but never received such diagnoses. They also were more likely to have subprime credit scores.
“We were motivated by anecdotes in which family members discover a relative’s dementia through a catastrophic financial event, like a home being seized,” said Lauren Nicholas, the lead author and a health economist at the University of Colorado School of Public Health. “This could be a way to identify patients at risk.”
The problems appeared early, with at least two consecutive payments skipped as much as six years before a diagnosis, and subprime credit 2½ years before.
Although smaller studies have pointed to an association between self-reported financial mismanagement and dementia, this is the largest and the first to use actual financial data, Nicholas added.
VOCAL CHANGES
In Japan, researchers have developed a machine-learning tool that scrutinizes phone conversations for signs of preclinical Alzheimer’s. Using audio files recorded during interviews last year, they compared healthy patients’ vocal features — pitch, intensity, silent intervals — with those with Alzheimer’s and found that the models could predict cognitive status.
IBM researchers have picked up elevated risk in writing tests, finding that word patterns and usage predicted later Alzheimer’s diagnoses. Any of these findings might, one day, be used for early screening.
Such approaches raise concerns about privacy, however. “Are people comfortable with a bank or an auto insurance company having and communicating that information?” Largent asked. “It becomes medical information in the hands of people who are not physicians.”
At the Penn Memory Center, where information is indeed in health professionals’ hands, “some people who are cognitively unimpaired, after testing in the clinic, indicate they’d like to be monitored,” she said. “Others find that unbelievably intrusive.”
FALSE RISK FACTORS?
Bioethicists have grappled for years with questions about informing patients of higher-than-normal risk for a feared disease for which there is, still, no effective treatment. Studies have shown that in research settings, results can be communicated safely and effectively. But fears of discrimination and stigma remain.
Even using established biomarkers like amyloid in PET scans, these advance findings aren’t definitive, which researchers take pains to point out to patients.
“It’s neither necessary nor sufficient to have these risk factors,” Largent explained. People with elevated amyloid have higher risk but may not progress to cognitive impairment; people without it can nevertheless develop dementia.
Still, Largent said, “I generally think having that information can be useful to people.”
In a number of studies, Largent has examined what happens when dementia risks are disclosed to patients and families. She has found that about one-third of patients respond to the information by changing their health behavior, undertaking legal and financial planning or taking other preparatory steps. “They do things like update their wills, draft advance directives, exercise more, maybe move closer to an adult child,” she said.