First in a three-part series

Life was relaxing and peaceful for Shigeru Suzuki until six years ago, when he realized that Hiroko, his wife of more than 30 years, was having problems doing simple chores.

The 77-year-old former employee of a major civil engineering firm recalls that, at first, he couldn't understand why Hiroko couldn't sort clothes as told. One day, he got irritated and snapped at her, pressing her to explain why she couldn't just remember to put the clothes away. Hiroko then tearfully replied: "It's not like I want to be forgetful."