THE HAGUE (Reuters) - The Dutch Supreme Court on Tuesday ruled that doctors could legally carry out euthanasia on people with advanced dementia who had earlier put their wishes in writing even if they could no longer confirm them because of their illness.

The ruling is a landmark in Dutch euthanasia legislation which up to now had required patients to confirm euthanasia requests. This had not been considered possible for mentally incapacitated patients like advanced dementia sufferers.

“A doctor can carry out an (earlier) written request for euthanasia from people with advanced dementia,” the Supreme Court said in a summary of its decision.

Doctors would need to take care that the other criteria of unbearable suffering with no hope of recovery were also fulfilled.

The ruling came after prosecutors brought a criminal case against a nursing home doctor carried out a mercy killing of a 74-year old Alzheimer sufferer, who had a living will confirming she wanted euthanasia. The euthanasia was carried out with the support of the patients’ family.

The doctor was cleared of all charges last year but prosecutors asked for a Supreme Court ruling in order to have a legal precedent because the law was still unclear on the issue, they said.

The case was seen as a test for the legal boundaries of euthanasia cases in the Netherlands, where assisted suicide and mercy killing is allowed by law under restricted conditions when overseen by medical professionals.

The conditions include that a patient is experiencing unbearable suffering with no hope of recovery, and wishes to die.