Approximately 7.7 million new cases of dementia are identified every year—which amounts to one new case every four seconds. Last year, dementia overtook heart disease as the leading cause of death in England and Wales. There are 850,000 people with dementia in Britain and this figure is expected to reach 1 million by 2025.
The dreaded Alzheimer’s disease is a severe form of dementia which affects as many as 1 in 8 people 65 and older, or an estimated 5.2 million Americans in 2013.
Alzheimer’s causes nerve cell death and tissue loss throughout the brain. As the disease gets worse, brain tissue shrinks and areas that contain cerebrospinal fluid become larger. The damage harms memory, speech, and comprehension.
Hannah Devlin reports for The Guardian, Feb. 21, 2017, on the disappointing news that drugs designed to treat Alzheimer’s have shown to be ineffective. Between 2002 and 2012, 99.6% of drugs studies aimed at preventing, curing or improving Alzheimer’s symptoms were either halted or discontinued.
Some believe that these failures may be, in part, because by the time Alzheimer’s is diagnosed, the disease has already caused irreparable damage to the brain, making it too late for treatment to help. That is why scientists now try to push the detection period back to the very subtle, early changes in Alzheimer’s disease.
Speaking at the American Association for the Advancement of Science (AAAS) on February 19, 2017 in Boston, Dr. Janet Cohen Sherman, clinical director of the Psychology Assessment Center at Massachusetts General Hospital, said: “With the growth in the aging population and the concomitant rise in the prevalence of Alzheimer’s disease, the need to define changes in cognitive functioning at the earliest stages, prior to disease onset, when treatments are likely to be most effective, has become increasingly important.”
Dementia is accompanied by not just memory loss, but characteristic language deficits. New research suggests that an early sign of Alzheimer’s may be rambling and long-winded anecdotes — subtle changes in speech style from Mild Cognitive Impairment (MCI), a known precursor of Alzheimer’s in which there is evidence of cognitive decline years before dementia takes hold. The scientists behind the work say it may be possible to detect these speech changes and predict if someone is at risk more than a decade before meeting the clinical threshold for an Alzheimer’s diagnosis.
At the AAAS meeting, Dr. Sherman presented new findings on distinctive language deficits in people with MCI, a precursor to dementia:
- Studies of novelist Iris Murdoch’s later works found that her vocabulary showed signs of Alzheimer’s years before her diagnosis.
- The final novels of famous crime writer Agatha Christie display increasingly repetitive and vague phrasing that suggests she was suffering from Alzheimer’s.
- A study of White House press conference transcripts found striking changes in President Ronald Reagan’s speech over the course of his presidency, whereas George H.W. Bush, who was a similar age when president, showed no such decline. Dr. Sherman said, “Ronald Reagan started to have a decline in the number of unique words with repetitions of statements over time. He started using more fillers, more empty phrases, like ‘thing’ or ‘something’ or things like ‘basically’ or ‘actually’ or ‘well’.”
- Sherman points out that the key is not long-winded, because many people without dementia are long-winded or verbose. The subtle change in speech style that indicates mild cognitive impairment is worsening mental imprecision.
So what’s an example of the kind of long-winded speech that is indicative of early Alzheimer’s?
In a study, the scientists compared the language abilities of 22 healthy young individuals, 24 healthy older individuals, and 22 people with MCI — the precursor to Alzheimer’s.
In one test, the subjects had to join up three words, for instance “pen”, “ink” and “paper”, the healthy volunteers typically joined the three in a simple sentence, while the MCI group gave circuitous accounts of going to the shop and buying a pen. Dr. Sherman explains that they MCI group “were much less concise in conveying information, the sentences they produced were much longer, they had a hard time staying on point and I guess you could say they were much more roundabout in getting their point across. It was a very significant difference.”
In another test, people were asked to repeat phrases read out by the investigator. Complex vocabulary or grammar was not a problem, but those with MCI appeared to have a mental block when they were given phrases involving ambiguous pronouns, such as “Fred visited Bob after his graduation”, which the scientists said required more mental agility to assign a meaning.
As Dr. Sherman summarizes the research findings:
“Our findings suggest that individuals with MCI may have more difficulty integrating syntax and semantics, impacting their ability to precisely and effectively convey meaning. Our findings suggest that the language changes cannot be accounted for by a decline in memory.”
Dr. Sherman hopes that in the next five years, researchers will develop a linguistic test for pre-Alzheimer’s mild cognitive impairment, as well as a determination whether engaging in language-based activities, including reading, writing and social activities, may serve as protective factors for dementia.
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