The Mainichi answers common questions readers may have about brain death decisions, after a child under the age of 6 was declared brain-dead on June 14, 2012, for the first time in Japan.

Question: What does it mean when a person is 'brain-dead'?

Answer: In ordinary death, a person's heart stops beating. Under the Organ Transplant Law, brain death is a state in which the person's brain has ceased to function entirely, and is making no recovery. In Japan, a person in such a state is deemed dead only if their organs are to be donated. When the brain stops working, the person's organs cannot function by themselves, and the person's heart stops beating if they are taken off respiration equipment. In a so-called "vegetative state," the brain stem functions controlling the breathing and circulatory functions remain, which is different from brain death.

Q: How is brain death determined in Japan?

A: In brain death decisions preceding organ transplants, at least two doctors who don't have anything to do with the transplant confirm five things: 1) The coma is so deep that the person doesn't feel pain; 2) The person's pupils don't respond to light; 3) The person has no brain-stem reflexes, such as coughing when the throat is stimulated; 4) No brain waves can be detected; 5) The person cannot breathe without aid.

For patients aged 6 or over, these checks are performed twice, at least six hours apart. The same tests apply to patients under the age of 6, but they are carried out at least 24 hours apart, on the grounds that children are more easily resuscitated. The patient is determined to be dead at the time the second check is completed.

Q: What are the procedures for receiving a brain-death judgment?

A: One of the prerequisites for diagnosing brain death is knowing that the person didn't previously refuse to have their organs donated. Children do not usually express a clear opinion about the issue. However, a legal revision in July 2010 made it possible for brain-death diagnoses to be handed down if a person's family gives their consent. At the same time, the stipulation that organ donors had to be aged 15 or over was removed.

Currently, coordinators from the Japan Organ Transplant Network, which serves as a bridge to patients who need organ transplants, confirm whether a person's family consents to the transplant, and a brain-death decision is subsequently made.

Q: Why did Japan allow brain-dead children to be included as organ donors?

A: Before the revision to the law, children who needed small organs received transplants from brain-dead children overseas. But there is a shortage of organs overseas, too, and Japan was criticized for not allowing transplants from children domestically. However, hospitals in Japan that diagnose brain death in children must check any suspicions of abuse, so that organs are not donated from children who die as a result of abuse. (Answers by Kosuke Hatta, Science and Environment Writer)