Is it possible to predict who will develop Alzheimer's disease simply by looking at writing patterns years before there are symptoms?
IBM researchers say 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 of whom had Alzheimer's. But, 7 ½ years earlier, all had been cognitively normal.
The men and women were participants in the Framingham Heart Study, a long-running federal research effort. 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 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 when all of them were cognitively normal. These subjects also made errors, such as spelling words wrong 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 AI program predicted, with 75% accuracy, who would get Alzheimer's disease, said the results published 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.
"What is going on here is very clever," said Dr. Jason Karlawish, a University of Pennsylvania Alzheimer's researcher. "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, amyotrophic lateral sclerosis, Parkinson's, frontotemporal dementia, bipolar disease and schizophrenia, among others.
But the IBM report breaks new ground, said Dr. Michael Weiner of the University of California, San Francisco.
"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 work to find subtle changes in language use by people with no obvious symptoms but who will go on to develop neurological diseases. Each neurological disease produces unique changes in speech, said Dr. Murray Grossman, a professor of neurology at Penn and the director of the university's frontotemporal dementia center.
He has been studying patients with a form of frontotemporal dementia. These patients exhibit apathy and declines in judgment, self control and empathy that are difficult to quantify. But speech 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, Grossman said. And they appear to be universal, not unique to English.