Mary had lost her speech without warning and was clearly frustrated. The staff suspected a small stroke as the cause, and they called me in to sit with Mary as the medical team assessed what to do next.

Mary's eyes brightened when I sat down, but she couldn't form my name on her lips. I opened my laptop and started a slideshow of pictures of prominent buildings from our community, where she had spent most of her adult life. She soon began to form the names of the historic sites—with difficulty at first, but with increasing clarity and ease.

Then I asked her about her childhood. She was able to say "Huntingdon," so I retrieved digital images of buildings in Huntingdon from the internet. She said haltingly that her father worked at a locomotive boiler factory there when she was a child. A Google search turned up a picture of the factory building.

Each internet image led to other memories. Within 40 minutes of my arrival, Mary was conversing normally with me. She was ...