When the Senses Become Confused

From The New York Times:

Brain A year and a half after the stroke, caused by a lesion the size of a lentil in a region of her midbrain, Dr. Roush began to feel tingling on her body in response to sounds. Today, more than ever, she feels sounds on her skin. The first time it happened, Dr. Roush was channel-surfing when she heard the voice of an announcer on a local FM station. When the announcer started to talk, she recalled, “I felt an unpleasant sensation on my left thigh, left arm, the back of my shoulder and even the outside of my left ear.”

“It was the kind of icky feeling that uniformly washes over you at a scary movie,” she continued. “I had to stop listening. It made me cringe.” Tony Ro, a psychologist from Rice University who has followed her case from the beginning, said Dr. Roush has a rare case of acquired synesthesia. Synesthesia is a condition marked by odd mixings of the senses. Sensory areas of the brain that do not normally communicate engage in cross-talk. Most synesthetes are born with such crossed connections. Some experience complex tastes, like apple or bacon, in response to words. Others feel complex shapes, like pyramids, in response to tastes. Many see colors attached to specific letters or numbers. In this case, Dr. Ro said, the crossed wiring developed as a consequence of the stroke.

More here.