Is it possible to predict who will develop Alzheimer’s disease simply by looking at writing patterns years before there are symptoms?
According to a new study by IBM researchers, the answer is yes.
And, they and others say that Alzheimer’s is just the beginning. People with a wide variety of neurological illnesses have distinctive language patterns that, investigators suspect, may serve as early warning signs of their diseases.
For the Alzheimer’s study, the researchers looked at a group of 80 men and women in their 80s — half had Alzheimer’s and the others did not. But, seven and a half years earlier, all had been cognitively normal.
The men and women were participants in the Framingham Heart Study, a long-running federal research effort that requires regular physical and cognitive tests. As part of it, they took a writing test before any of them had developed Alzheimer’s that asks subjects to describe a drawing of a boy standing on an unsteady stool and reaching for a cookie jar on a high shelf while a woman, her back to him, is oblivious to an overflowing sink.
The researchers examined the subjects’ word usage with an artificial intelligence program that looked for subtle differences in language. It identified one group of subjects who were more repetitive in their word usage at that earlier time when all of them were cognitively normal. These subjects also made errors, such as spelling words wrongly or inappropriately capitalizing them, and they used telegraphic language, meaning language that has a simple grammatical structure and is missing subjects and words like “the,” “is” and “are.”
The members of that group turned out to be the people who developed Alzheimer’s disease.
The A.I. program predicted, with 75 percent accuracy, who would get Alzheimer’s disease, according to results published recently in The Lancet journal EClinicalMedicine.
“We had no prior assumption that word usage would show anything,” said Ajay Royyuru, vice president of health care and life sciences research at IBM Thomas J. Watson Research Center in Yorktown Heights, N.Y., where the A.I. analysis was done.
Alzheimer’s researchers were intrigued, saying that when there are ways to slow or stop the illness — a goal that so far remains elusive — it will be important to have simple tests that can warn, early on, that without intervention a person will develop the progressive brain disease.
“What is going on here is very clever ” said Dr. Jason Karlawish, an Alzheimer’s researcher at the University of Pennsylvania. “Given a large volume of spoken or written speech, can you tease out a signal?”
For years, researchers have analyzed speech and voice changes in people who have symptoms of neurological diseases — Alzheimer’s, ALS, Parkinson’s, frontotemporal dementia, bipolar disease and schizophrenia, among others.
But, said Dr. Michael Weiner, who researches Alzheimer’s disease at the University of California, San Francisco, the IBM report breaks new ground.
“This is the first report I have seen that took people who are completely normal and predicted with some accuracy who would have problems years later,” he said.
The hope is to extend the Alzheimer’s work to find subtle changes in language use by people with no obvious symptoms but who will go on to develop other neurological diseases.
Each neurological disease produces unique changes in speech, which probably occur long before the time of diagnosis, said Dr. Murray Grossman, a professor of neurology at the University of Pennsylvania and the director of the university’s frontotemporal dementia center.
He has been studying speech in patients with a behavioral form of frontotemporal dementia, a disorder caused by progressive loss of nerves in the brain’s frontal lobes. These patients exhibit apathy and declines in judgment, self control and empathy that have proved difficult to objectively quantify.
Speech is different, Dr. Grossman said, because changes can be measured.
Early in the course of that disease, there are changes in the pace of the patients’ speech, with pauses distributed seemingly at random. Word usage changes, too — patients use fewer abstract words.
These alterations are directly linked to changes in the frontotemporal parts of the brain, Dr. Grossman said. And they appear to be universal, not unique to English.
Dr. Adam Boxer, director of the neurosciences clinical research unit at the University of California, San Francisco, is also studying frontotemporal dementia. His tool is a smartphone app. His subjects are healthy people who have inherited a genetic predisposition to develop the disease. His method is to show subjects a picture and ask them to record a description of what they see.
“We want to measure very early changes, five to 10 years before they have symptoms,” he said.
“The nice thing about smartphones,” Dr. Boxer added, “is that you can do all kinds of things.” Researchers can ask people to talk for a minute about something that happened that day, he said, or to repeat sounds like tatatatata.
Dr. Boxer said he and others were focusing on speech because they wanted tests that were noninvasive and inexpensive.
Dr. Cheryl Corcoran, a psychiatrist at Icahn School of Medicine at Mount Sinai in New York, hopes to use speech changes to predict which adolescents and young adults at high risk for schizophrenia may go on to develop the disease.
Drugs to treat schizophrenia may help those who are going to develop the disease, but the challenge is to identify who the patients will be. A quarter of people with occasional symptoms saw them go away, and about a third never progressed to schizophrenia although their occasional symptoms persisted.
Guillermo Cecchi, an IBM researcher who was also involved in the recent Alzheimer’s research, studied speech in 34 of Dr. Corcoran’s patients, looking for “flight of ideas,” meaning the instances when patients were off track when talking and spinning off ideas in different directions. He also looked for “poverty of speech,” meaning the use of simple syntactic structures and short sentences.
In addition, Dr. Cecchi and his colleagues studied another small group consisting of 96 patients in Los Angeles — 59 of whom had occasional delusions. The rest were healthy people and those with schizophrenia. He asked these subjects to retell a story that they had just heard, and he looked for the same telltale speech patterns.
In both groups, the artificial intelligence program could predict, with 85 percent accuracy, which subjects developed schizophrenia three years later.
“It’s been a lot of small studies finding the same signals,” Dr. Corcoran said. At this point, she said, “we are not at the point yet where we can tell people if they are at risk or not.”
Dr. Cecchi is encouraged, although he realizes the studies are still in their infancy.
“For us, it is a priority to do the science correctly and at scale,” he said. “We should have many more samples. There are more than 60 million psychiatric interviews in the U.S. each year but none of those interviews are using the tools we have.”
