According to recent research people with superior language skills early in life may be less likely to develop Alzheimer's disease later in life despite having hallmark signs of the disease. 

Study author Juan C. Troncoso, MD, with Johns Hopkins University in Baltimore said, "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."

The researchers studied the brains of 38 Catholic nuns after death. The participants were part of the Nun Study, an ongoing clinical study of Catholic sisters of the School Sisters of Notre Dame congregation living in the United States.

They divided the women into two groups where one group had memory problems and signs of dementia damage in the brain and the second group whose memory was unaffected irrespective of whether or not they exhibited signs of dementia damage.

The researchers analyzed essays that were written by 14 of the women when they joined the convent in their late teens or early 20's. The essays were assessed for language complexity and grammar and they studied the average number of ideas expressed for every 10 words

They found that women with good language scores early in life were less likely to have memory problems even if their brains showed signs of dementia damage. The study found that language scores were 20 % higher in the women without memory problems compared to those with memory problems. The grammar score did not show any difference between the two groups.

"Despite the small number of participants in this portion of the study, the finding is a fascinating one," Troncoso said. "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."

The study also highlighted that brain cells were largest in women who retained a normal memory despite showing signs of disease in their brains, which researchers said could suggest that a growth in brain cells might be part of the body's early response to the onset of dementia, and this might help to prevent memory impairment.

Dr Troncoso said: "Perhaps mental abilities at age 20 are indicative of a brain that will be better able to cope with diseases later in life."

Dr Susanne Sorensen, head of research at the Alzheimer's Society said although the findings were interesting, "however, the research is in a very small, select group and it would be difficult to say at this stage if language skills could really predict dementia."

The study appears online in the journal Neurology and was supported by the Johns Hopkins University Alzheimer's Disease Research Center, the National Institutes of Health, the Nun Study, the National Institute on Aging, the University of Kentucky Alzheimer's Disease Center, the Abercrombie Foundation and the Kleberg Foundation.