July 13, 2009

Language Skills May Delay Alzheimer’s

People who have superior language skills early in life may be less likely to develop the symptoms of Alzheimer's disease as they age.

"A puzzling feature of Alzheimer's disease is how it affects people differently," study author Juan C. Troncoso, MD, at Johns Hopkins University in Baltimore is quoted as saying. "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."

Researchers examined the brains of 38 Catholic nuns after death. The participants were part of an ongoing clinical study of Catholic sisters living in the United States. Scientists determined two groups: women with memory problems and Alzheimer's disease hallmarks in the brain and women with normal memory, with or without signs of Alzheimer's disease in the brain.

The researchers analyzed essays written by 14 participants as they entered the convent in their late teens or early twenties. The analysis measured the average number of ideas expressed for every 10 words, and also studied the complexity of the grammar in each essay.

Researchers found that language scores (measuring number of ideas) were 20 percent higher in those women who did not develop memory problems later in life. The grammar scores, however, 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 measured how growth in brain cells might be part of the brain's early response to Alzheimer's disease or how these cells may prevent memory impairment, despite a large amount of Alzheimer's disease lesions. "Perhaps mental abilities at age 20 are indicative of a brain that will be better able to cope with diseases later in life," said Dr. Troncoso.

SOURCE: Neurology, July 9, 2009