I was fascinated and horrified by the story of Clive Wearing (video below), once a good musician and conductor (and still can play music) but, laid low in 1983 by a herpes simplex virus that damaged his brain, he was left with a memory that lasts only seven seconds. He can’t remember anything that took place more than seven seconds earlier, and it’s given him what he considers a living death. Each time he sees his wife it’s as if he meets a new person. His consciousness is completely reset every few seconds.
It’s ineffably sad but also scientifically fascinating. Why seven seconds? What kind of damage would impose a time span like that?
I believe Oliver Sacks wrote about people like this, but I can’t remember whether he wrote about Wearing.
And a bit from Wikipedia:
Wearing developed a profound case of total amnesia as a result of his illness. Because of damage to the hippocampus, an area required to transfer memories from short-term to long-term memory, he is completely unable to form lasting new memories – his memory only lasts between 7 and 30 seconds. He spends every day “waking up” every 20 seconds, “restarting” his consciousness once the time span of his short term memory elapses (about 30 seconds). During this time, he repeatedly questions why he has not seen a doctor, as he constantly believes he has only recently awoken from a comatose state. If engaged in discussion, Wearing is able to provide answers to questions, but cannot stay in the flow of conversation for longer than a few sentences and is angered if asked about his current situation.
Wearing remembers little of his life before 1985; he knows, for example, that he has children from an earlier marriage, but cannot remember their names. His love for his second wife, Deborah, whom he married the year prior to his illness, is undiminished. He greets her joyously every time they meet, either believing he has not seen her in years or that they have never met before, even though she may have just left the room momentarily. When he goes out dining with his wife, he can remember the name of the food (e.g. chicken); however he cannot link it with taste, as he forgets what food he is eating by the time it has reached his mouth.
In a diary provided by his caretakers, Wearing was encouraged to record his thoughts. Page after page was filled with entries similar to the following:
8:31 AM: Now I am really, completely awake.
9:06 AM: Now I am perfectly, overwhelmingly awake.
9:34 AM: Now I am superlatively, actually awake.