During the day, Lawrence Neumann was a mild mannered man, considerate, kind and loving to his wife of many years, Bonnie.
In the middle of the night, as they tried to sleep, he became someone else -- screaming obscenities, grunting, kicking, punching Bonnie in the arm, violently hurling himself out of bed.
For 16 years, the couple from Streator, Ill., had no idea what was happening or why night after night. The doctors they consulted were at a loss to explain the strange symptoms.
"Nobody seemed to know anything about it," said Lawrence, 73.
Relief came at long last in the form of a diagnosis from a neurologist at Northwestern University's Feinberg School of Medicine. Lawrence had a little known condition, REM sleep behavior disorder, in which people act out their dreams, unconsciously, during sleep. That diagnosis was a turning point, since the condition is easily treatable.
Nine out of 10 people who suffer the disorder are men. Most are 50 or older, although new research is finding a higher prevalence of the disorder in younger adults as sleep problems gain more attention, according to Dr. Bradley Boeve, a professor of neurology at the Mayo Clinic in Rochester, and a leading expert on the condition.
"Several patients we've seen, their spouse will describe first encountering this on their wedding night," he said.
Estimates suggest one in every 200 adults has the strange affliction, caused by a dysfunction in a part of the brain that suppresses muscle activity while people are in REM sleep, a dream-filled phase of slumber.