In the last post, I talked about adaptations: how my husband Dan had adapted to the microgravity of spaceflight and how I had adapted to seeing with crossed eyes. (See also my book, Fixing My Gaze). Not all adaptations are beneficial, but in this post I want to describe a remarkable adaptation and how clinical tests failed to reveal it.

When Dan was a young doctor in training, he was asked to examine an elderly man who had suffered from polio as a child. Full of textbook knowledge regarding muscles and locomotion, Dan confidently entered the examining room, took mental note of the wheelchair that had been placed in the corner, introduced himself to the patient, and began to test the strength of the patient's walking muscles. Upon leaving the examining room, my husband reported the condition of his patient to the senior physician.

"Can the patient walk?" asked the more experienced doctor. Dan had not observed that skill, though he was confident that the patient's weak walking muscles prevented that possibility. The two went back to the examining room and asked the patient if he could walk, and to my husband's astonishment, the old man swiftly stood up and strolled across the room. The patient had taught himself to substitute alternative muscles for the weak ones, and his adaptation was so complete that it was difficult to see any abnormality in his gait.