Mrs Lee noticed it first in a grocery list. Her husband, a retired lawyer who once commanded a courtroom and remembered legal cases for years, began writing the same items two or three times on the list: bread, eggs, soap, eggs, butter, bread. At first, she ignored it – do we not all get scatty with age? Perhaps her husband was distracted mid-list-writing. What was less easy to dismiss was when he forgot the way home from his local supermarket. It took the family 11 months and four different...