Wisdom on Alzheimer’s Disease Gained from Nuns
by Susan Leem, associate producer
Dr. Karen Santa Cruz of the University of Minnesota examines one of the 670 brains in the Nun’s Study, looking for signs of dementia. The brain pictured here is more than 75 years old and still looks healthy says Dr. Santa Cruz. (photo: Lorna Benson/MPR News)
The nuns of the School Sisters of Notre Dame made headlines in Time magazine a decade ago for making an unexpectedly profound contribution to how we understand Alzheimer’s disease.
Looking for a research project, David Snowdon became interested in the convent after a graduate student, a former nun, told the young epidemiologist about a retired community of nuns living out their days in Mankato, Minnesota. These women turned out to be ideal for research into aging because of their similarities in lifestyle. Snowdon didn’t know exactly what he was going to find among these nuns, but struck gold when finding their personal records in an old olive green file cabinet. The biographical essays they wrote as young women in their early 20s held clues to the way they aged over 50 years later.
What Snowdon found was a correlation between low grammatical complexity in their writing and low “idea density” among sisters who had Alzheimer’s disease. An example of a low-scoring sample:
“My father, Mr. L.M. Hallacher, was born in the city of Ross, County Cork, Ireland, and is now a sheet-metal worker in Eau Claire.”
On the other hand, a high-scoring essay looks more complex:
“My father is an all-around man of trades, but his principal occupation is carpentry, which trade he had already begun before his marriage with my mother.”
These high-scoring writers avoided dementia in their later years and performed better on other cognitive tests. Later, Dr. Snowdon pursuaded the nuns to donate their brains to science. Among the participating nuns who died, none of the high-density ideas nuns’ brains showed evidence of Alzheimer’s disease, while it was physically present in all of those with low idea density.
Researchers at the University of Minnesota now carry this research forward, trying to figure out why some of the nuns’ brains look diseased post-mortem, but before death, these women managed to live out their final days without dementia.
Another researcher in Canada has recently discovered that bilingual speakers can also stave off Alzheimer’s by a few years more than monolingual speakers.
Could there be a protective quality to maintaining your linguistic skills? Or is it that these nuns have always had a bit extra reserve of cognitive ability to weather the ravages of aging? Thankfully, this research provides more insights into questions like these as this massive longitudinal study involving over 600 nuns continues.
