Eventually, a doctor identified the problem as Alzheimer's disease, a slow deterioration of mental faculties.

CNN: SPECIAL REPORT: HEALTH

You can easily and inexpensively avoid guardianship or conservatorship proceedings by executing durable powers of attorney while you still have your mental faculties.

FORBES: Estate Planning Overview and Objectives

The mother's lawyer, Fabian Farias, said Edith was "not in full control of her mental faculties" and said her physical and psychological wellbeing were in danger.

BBC: Latin America & Caribbean

Superior mental faculties, such as language and the ability to engage in abstract problem solving, are the sort of explanations that are currently all the rage.

ECONOMIST: Gaining the upper hand

Once the robot can do this the researchers plan to disrupt the memories in a bid to recreate the gradual loss of mental faculties seen in diseases such as Alzheimer's and Parkinson's.

BBC: Rat-brain robot aids memory study