Clues from Language
Researchers think that cognitive impairment starts a long time before the signs of dementia are apparent to outsiders, reported Adrienne Day in Nautilus. Such is the case with authors like Iris Murdoch, whose 26th novel became a challenge for her to write and for readers to understand. Two years after its publication, she was diagnosed with dementia, clearly a process that had been manifesting itself beforehand.
Several years later, Peter Garrard, a professor of neurology, focusing on dementia, took an interest in Murdoch’s work. He had studied for his Ph.D. under John Hodges, the neurologist who had diagnosed Murdoch with Alzheimer’s. Before that, he had studied ancient literature when computational language analysis, or computational linguistics, was used to create lists of all of the word types and word tokens in a piece of text. He decided to apply a computational technique to books by Murdoch. Garrard wondered if it might be possible to use the technique to sift through three of Murdoch’s books, written at different times in her life, to determine whether signs of dementia were apparent.
Scientists say that Alzheimer’s disease is caused by cell death and tissue loss because of abnormal accumulation of plaques and protein tangles in the brain. Language is affected when areas of the brain responsible for language comprehension and production, are impacted by the proliferation of disease. Thus, language offers insight into the onset and development of Alzheimer’s pathology. In Murdoch’s case, the rich language makes the study exceptionally interesting. If computer analysis can help to uncover the earliest instances of mild cognitive impairment, before the obvious symptoms occur, it could be important for researchers who hope to diagnose Alzheimer’s before too much damage has happened to the brain.
Understanding changes in language patterns could be important to Alzheimer’s therapies, according to Barbara Lust, a professor of human development, linguistics, and cognitive science at Cornell University, who studies language acquisition and early Alzheimer’s. As she said, Caregivers don’t usually notice very early changes in language, but this could be critically important both for early diagnosis and also in terms of basic research. A lot of researchers are trying to develop drugs to halt the progression of Alzheimer’s, and they need to know what the stages are in order to halt them.”
Before Garrard’s study, researchers defined language as a marker of Alzheimer’s disease. A patient’s vocabulary becomes smaller, and the patient uses fewer specific words as the disease progresses. People with Alzheimer’s also speak haltingly as they try to find words.
Since Garrard’s study in 2005, other novelists’ work has been analyzed in the same fashion, and language decline has become an accepted marker for Alzheimer’s. Computer programs that analyze language for cognitive deficits are coming, showing promise for early Alzheimer’s diagnosis. Hopefully, early screening can pave the way for early treatment.