Early Language Skills Predict Dementia Risk

The American Academy of Neurology reports that people who exhibit higher language skills as adolescents and young adults in their 20s are far less likely to develop dementia, the Alzheimer's disease, or another type of neurodegenerative mental conditions than others. The research, which is published in the July 9th online issue of the scientific journal Neurology, also shows that diseases such as Alzheimer's affect people differently, and that the level of linguistic development may be an indicator as to the chances someone has of developing the conditions.

“A puzzling feature of Alzheimer's disease is how it affects people differently. One person who has severe plaques and tangles, the telling signs of Alzheimer's disease in their brains, may show no symptoms affecting their memory. Another person with those same types of plaques and tangles in the same areas of the brain might end up with a full-blown case of Alzheimer's disease. We looked at how language ability might affect the onset of symptoms,” Johns Hopkins University expert Juan C. Troncoso, MD, the lead author of the new paper, explains.

In the new study, the researchers investigated the brains of some 38 Catholic nuns, after the sisters had died. They were part of an ongoing clinical study of Catholic sisters from the School Sisters of Notre Dame, called the Nun Study. The brains were divided into two groups. In the first one, the scientists placed the brains that belonged to persons known to have had memory problems, with clear signs of the Alzheimer's disease, while, in the second, they placed the brains of nuns who had reported a normal-functioning memory, even if they exhibited the hallmarks of the neurodegenerative condition or not.

Afterwards, the experts looked at essays written by the nuns when they entered the monastery, most of them teens or young adults, in their early 20s. The survey found that language scores were about 20 percent higher than the average for the nuns that, at the end of their lives, showed no sign of memory decay. Conversely, for the others, less ideas expressed per ten words, as well as the overall tone of the essay and the lack of complexity in their speech were deemed to be a risk factor for Alzheimer's.

“Despite the small number of participants in this portion of the study, the finding is a fascinating one. Our results show that an intellectual ability test in the early 20s may predict the likelihood of remaining cognitively normal five or six decades later, even in the presence of a large amount of Alzheimer's disease pathology,” Troncoso explains. “Perhaps mental abilities at age 20 are indicative of a brain that will be better able to cope with diseases later in life.”