What are the odds of outliving my brain?

If I had to live the rest of my life without breaking a sweat, I could cope. Strapping lads could carry me up subway steps on a litter. Somehow, I’d get my brain from place to place. Vigor, agility, beauty . . . those, too, I can acknowledge losing, though not without a struggle. They don’t hold a candle to my deepest terror: that I’ll lose my mind. Just how reasonable is this fear?

Misplaced keys, forgotten names, a “tip of the tongue” spazzout — that’s all it takes to convince most of us that a few more precious neurons have decamped for good. If Alzheimer’s lurks in our genes, we might as well throw in the towel. After all, everyone’s getting it (or Parkinson’s, or both), right?  Now for some facts, many from Successful Aging, the MacArthur Foundation’s interdisciplinary study of effective functioning in later life:

• No more than 10 percent of all elderly people (aged 65 to 100 or more), suffer from Alzheimer’s.
• The incidence of Alzheimer’s is not on the rise. Rather, because the number of older people is growing, the diagnosis is becoming more common. 

• The percentage of people with Alzheimer’s disease does increase with age:  at least one study suggests that among people aged 85 and up, 30 to 50% may have some degree of Alzheimer’s disease. Emphasis added.

• While genes play some role, especially in early-onset Alzheimer’s (the form that shows up in middle age), the MacArthur study explains that “a purely genetic explanation is almost certainly wrong.”  Even identical twins who develop the disease do so at different ages, because environment and behavior affect onset.
• The great majority of older people remain cognitively competent and physically independent. Only five percent are in nursing homes.

As I’ve observed on this blog and as John W. Rowe and Robert L. Kahn write in Successful Aging, research demonstrates “the remarkable and enduring capacity of the aged brain to make new connections, absorb new data, and thus acquire new skills.” Unsurprisingly, this involves effort and risk: embracing the new doodad instead of waiting till some kid comes by to program the damn thing.  (Guilty!) Look at journalist Daniel Schorr, who had to scramble to find a telephone to file his first story in the 1920s , and who just joined Twitter.  “It shows you can teach an old dog new tricks,” he tweeted on February 28th, and yesterday, “At 92, I have become a grandfather for the first time.” Congratulations, Mr. Schorr.