The first time I learnt about dementia was when my father was struck with it in his late seventies. It was painful watching such an intelligent man fall into this deep abyss of dementia, from which he could never revive. Dementia made him silent. He forgot to speak, to read, to write and to recognize anyone. That was not all. He often confused his wife, with his mother.

My mother was in her late sixties then. I cannot understand this association in his brain between my mother and his. I know...