The nuns are exceptional subjects because their lives are so similar and because they have a wealth of information on file.

Most became nuns as young women, lived in convents, had similar health care and nutrition, remained physically and mentally active throughout their lives and often lived to very old age.

The nuns who volunteered for the study agreed to open their personal histories to be researched and most agreed to donate their brains after death.

Snowdon released a book in 2001 called “Aging With Grace,” which recounted many of his findings so far.

One of the conclusions has been that nuns who expressed themselves more positively and used more complex language in the journals they wrote as girls lived longer and had a lower incidence of Alzheimer’s.

Snowdon was able to get access to a treasure-trove of autobiographies the nuns wrote when they were young because the journals were kept at Good Counsel and other convents.

He found that nuns who packed a lot of detailed thoughts into few words had fewer cases of Alzheimer’s, suggesting the disease may be a lifelong process that could be predicted in young people.

Research on the brains of the nuns have shown that small strokes or head injuries appear to contribute to the dementia of Alzheimer’s. (More about the nun study can be found at: www.mc.uky.edu/nunnet.)

Burg is survived by a brother, Gerald Burg of St. Peter. Mass will be 10:30 a.m. today in Good Counsel Chapel. Visitation will be one hour before the funeral.