WASHINGTON — Even before became the oldest elected president, his mental state was a political issue. His adversaries often suggested his penchant for contradictory statements, forgetting names and seeming absent-mindedness could be linked to .
In 1980, Mr. Reagan if White House doctors found him mentally unfit. Years later, those doctors and key aides told me they .
Now a clever new analysis has found that during his two terms in office, subtle changes in Mr. Reagan’s speaking patterns linked to the onset of dementia were apparent years before doctors diagnosed his in 1994.
The , published in The Journal of Alzheimer’s Disease by researchers at Arizona State University, do not prove that Mr. Reagan exhibited signs of dementia that would have adversely affected his judgment and ability to make decisions in office.
But the research does suggest that alterations in speech one day might be used to predict development of Alzheimer’s and other neurological conditions years before symptoms are clinically perceptible.
Detection of dementia at the earliest stages has become a high priority. Many experts now believe that yet-to-be-developed treatments are likely to be effective at preventing or slowing progression of dementia only if it is found before it significantly damages the brain.
The “highly innovative” methods used by the researchers may eventually help “to further clarify the extent to which spoken-word changes are associated with normal aging or predictive of subsequent progression to the clinical stages of Alzheimer’s disease,” said Dr. Eric Reiman, the director of the Banner Alzheimer’s Institute in Phoenix, who was not involved in the new study.
Visar Berisha and Julie Liss, professors of speech and hearing science at the university, compared transcripts of all 46 news conferences that Mr. Reagan held to the 101 sessions President George H. W. Bush held in his term.
The researchers assessed changes in the presidents’ speech patterns with a new algorithm based on a technique used by others to analyze changes in writing by novelists.
In an interview, Dr. Berisha said he did not set out to study Mr. Reagan, but found he was the only individual with progressive dementia for whom long-term transcript information is publicly available. He chose Mr. Bush because he was most comparable in age to Mr. Reagan at the start of their presidencies, and both men served during roughly the same decade.
Age and era are important issues for comparison because they can influence language measures. Mr. Reagan was 69 when he became president, and Mr. Bush was 64. in 2004.
The researchers found no changes in the speaking patterns of Mr. Bush, who is not known to have developed Alzheimer’s. But in Mr. Reagan’s speech, two measures — use of repetitive words, and substituting nonspecific terms like “thing” for specific nouns — increased toward the end of Mr. Reagan’s presidency, compared with its start. A third measure, his use of unique words, declined.
The researchers’ methodology was not designed to determine whether the changes were present in Mr. Reagan’s rare early news conferences, Dr. Berisha said. Other factors — like a deliberate decision to reduce the complexity of his speaking style, or the injury, surgery and from — could account for the language changes they found, Dr. Berisha said.
In 1984, Mr. Reagan’s poor performance in his first presidential debate with Vice President Walter Mondale renewed questions about his mental capacity. A study published in 1988 suggested that Mr. Reagan had some cognitive impairment during his debates with President Jimmy Carter and Mr. Mondale, but the authors said that their findings were insufficient to conclude that the changes affected Mr. Reagan’s policy judgments and ability to make decisions.
The new research is part of a larger effort to develop objective tests that would serve as bellwethers for Alzheimer’s and other neurological diseases, Dr. Berisha said.
While the new study is “very clever,” said Dr. Richard Caselli, an Alzheimer’s expert at the Mayo Clinic in Scottsdale, Ariz., further research involving larger numbers of individuals is necessary to prove the methods actually predict dementia.
Imperceptible cognitive decline often predates by many years the precipitous downturn that occurs once compensatory strategies, like relying on well-rehearsed phrases and simple words, fail and an individual can no longer mask his cognitive deficit.
Dr. Berisha wanted to determine whether natural language processing and algorithms could be used to detect any such changes in news conferences, because spontaneous responses to questions require greater cognitive effort than a rehearsed speech does.
Sharing thoughts and ideas through spoken communication is a fragile process. Even the simplest verbal response requires a complex sequence of events. The brain must recall the words to best convey a message, put them in proper sequence, and then signal the muscles required to produce speech.
The slightest damage to brain areas that orchestrate these events can produce speech difficulties.
Earlier studies have shown that certain linguistic biomarkers change with disease progression. Spoken vocabulary size declines, for instance, and use of indefinite nouns increases.
Studies of a small group of American nuns have shown a strong relationship between the complexity of the language the women used in handwritten autobiographical essays when they were young and their cognitive health many decades later.
Canadian researchers have reported that analyses of syntax in novels by Iris Murdoch and Agatha Christie (Ms. Murdoch died of Alzheimer’s; Ms. Christie is suspected to have had it.) The same analysis applied to the healthy P. D. James, who died at 94 last year, did not find signs of dementia.
Dr. Berisha said his team intended to conduct similar analyses of transcripts of other presidents, as well as news conference transcripts of National Football League players known to have sustained .
He and his team also hope to devise a study in which the conversations between physicians and patients are recorded at each visit and later analyzed to determine if speech and language changes can predict the appearance of dementia.
If the day comes when such tests to detect the earliest stages of Alzheimer’s and other neurological diseases become widely established, a question will arise about their use to screen candidates for the White House and other public offices.