A 62-year-old man led a choir through a flawless rehearsal and performance, but by the end of the day he could remember none of the day’s events.
He was experiencing transient global amnesia (TGA), a malady believed until the 1950s to be the product of hysteria or malingering, said Joshua R. Steinerman, M.D., a senior resident in neurology who described the disorder at clinical neuroscience grand rounds in June.
Physicians now know what triggers TGA, without knowing what causes it. Triggers include swimming in cold water, sexual intercourse, an emotional event, stress and exertion. “The history and proximal events leading to the episode are crucial,” Steinerman said.
Episodes usually last four to six hours. Sufferers—typically people between the ages of 50 and 79—know something’s wrong, but they can’t recall answers to the questions they ask as they try to orient themselves.
Over the years, several theories have been proposed about what causes TGA. “None is entirely satisfactory,” Steinerman said. “The great thinkers who proposed mechanisms have always hedged their bets.”