Oct. 31, 2003 -- A mystery has been brewing about late president Franklin Delano Roosevelt, and the paralysis that struck him in midlife.

A group of researchers has found evidence that Guillain-Barre syndrome -- not polio - may have been the cause of Roosevelt's (FDR's) paralysis.

The news comes a half-century after FDR's presidency, which spanned the Great Depression of the 1930s and most of World War II. It is published this month in the Journal of Medical Biography.

The paralysis struck him in 1921, when FDR was 39 years old, writes researcher Armond S. Goldman, MD, emeritus professor of pediatrics at the University of Texas Medical Branch in Galveston.

It happened while FDR was vacationing with his family on Campobello Island, New Brunswick. He had fallen into the cold waters of the Bay of Fundy on Aug. 9. The next day he sailed, spent several hours helping put out a fire, even jogged a few miles, which usually left him "glowing," he said later. But that night, he went to bed early, chilled and very tired.

The next morning, one leg was weak; by afternoon, it was paralyzed. Quickly, the paralysis overtook all his extremities, and although he regained function of the upper limbs, his legs never recovered.

At the time, doctors diagnosed the disease as poliomyelitis, which was at epidemic proportions in the northeast U.S., where FDR lived -- even though few adults over age 30 had contracted polio. Polio was one of few known causes of paralysis.

But many of FDR's symptoms did not match polio -- they were more typical of Guillain-Barre syndrome: the progression of his paralysis, the numbness, extreme prolonged pain, and the pattern of recovery from the paralysis.

Whereas patients with mild to moderate Guillain-Barre syndrome usually recover entirely, those with severe disease who are not treated by modern methods often experience permanent paralysis, notes Goldman.

The mystery of FDR's illness will likely never be completely solved, since several diagnostic tests were not available at the time, he says. Even if Guillain-Barre syndrome had been diagnosed in 1921, Roosevelt's outcome would have been the same since treatment was not discovered until the late 20th century.