Again, we look at Mr. Sharon's age, which suggests that there were other conditions existing that may have caused his stroke. Also, in this country we use the procedure very cautiously. The guidelines are very prudent and restrictive.

The condition is actually fairly common during gestation, but often corrects itself. In individuals who have it, it may go unnoticed unless a stroke occurs, generally in a very young person, which triggers further exploration. Mr. Sharon was definitely way above the average age for the PFO procedure, and many of us believed that there were actually other causes for his stroke.

The conventional approach in this country is not to proceed with the PFO until at least six to eight weeks have elapsed from the time of the stroke. Our protocol also dictates that the procedure is not done until and unless there has been a second stroke, except under certain conditions.

The rate of success is high, under the appropriate circumstances.

Our fMRI scanning reveals that middle age represents the transition between the patterns observed in youth to that found in old age. The see-saw imbalance in the two frontal lobe areas is not as significant as in older adults, but the functional changes are detectable by middle age.

We recommend that at age 50 most adults think about an initial colonoscopy. If someone has had a colonoscopy when they are 50 and they don't have any polyps or a family history of cancer, then we recommend a colonoscopy every 10 years.