Your Brain, Your Disease, Your Self - The New York Times

There are many kinds of memory loss.  The one that is most profoundly disruptive to the family's ability to recognize the person they love is the dementia that destabilizes moral understanding.

As monstrous as neurodegenerative disease is, its powers of identity theft have been greatly exaggerated. Remarkably, a person can undergo significant cognitive change and still come across as fundamentally the same person.

What makes us recognizable to others resides almost entirely within a relatively narrow band of cognitive functioning. It is only when our grip on the moral universe loosens that our identity slips away with it.

Your Brain, Your Disease, Your Self - The New York Times