True story: A novelist gets up one morning and snatches the newspaper off his doorstep only to find the words appear to be written in some unintelligible script, perhaps Cyrillic. He suspects a practical joke but soon realizes he has lost the ability to read. The novelist finds he can still write, but can’t proofread what he’s just set down. Determined, he finds a way to produce another novel.
In his latest book, Sacks, a neurologist, explores the loss of various kinds of visual perception, including this real-life example of a condition called alexia, and how people compensate for it.
As in his previous books, Sacks excels at tracking down fascinating case studies. He describes a concert pianist who sits down to play a Mozart concerto in front of an audience but, like the novelist, she finds the sheet music unrecognizable. She plays it from memory. As months pass objects seem to hide in plain sight, yet she retains the ability to play piano for years.
The most stunning vignette concerns Sacks himself, who lacks the ability to recognize faces. He struggles to identify even his coworkers but finds ways to manage. “When I see a youngish woman with a Rhodesian ridgeback hound, I realize that she lives in the apartment next to mine,” Sacks writes. Many people suffer from this problem, called prosopagnosia, and most just live with it, he says.
Sacks gives the reader a guided tour of the brain areas where defects or damage can cause these perception problems in people with otherwise normal vision. In closing, he discusses the loss of binocular vision — which Sacks himself has had to endure — and blindness, exploring how people who have lost all sight rely on the mind’s eye.
Knopf, 2010, 288 p., $26.95.