Here's another article about the government's belated relaxation of its certification criteria.
http://www.japantimes.co.jp/news/2014/01/11/national/changes-in-recognition-of-minamata-disease-victims-proposed/
Changes in recognition of Minamata disease victims proposed
The Environment Ministry plans to propose changes to make it possible for people who suffer only from sensation disorders to be recognized as victims of the Minamata mercury-poisoning disease, officials ...