In truth, the disease can trigger a complex array of emotions.
They may include, on occasion, anger and violence.
These elements seem to have combined for tragedy Saturday at an assisted living home in Lakewood.
Homer Castor, an 87-year-old man with Alzheimer's, has been arrested for the beating death of Gerald Propp, his 76-year-old roommate, who also suffered from the condition.
At about 6 a.m. on Saturday, February 21, according to the Lakewood Police Department, officers were dispatched to Atria Applewood, an assisted living facility on the 2700 block of Youngfield Street that specializes in what its website describes as "memory care services."
The cops were called to investigate what was originally reported as an assault involving two elderly male residents.
As they arrived, a man later identified as Propp was being placed in an ambulance and rushed to an area hospital with serious injuries from blunt-force trauma.
Atria personnel told investigators they heard screaming coming from one of the rooms, and when they rushed to find out what was happening, they found Castor, 87, walking away from Propp, whose face was covered with blood.
More details appear in an arrest affidavit accessed by Reuters. The beating was apparently so severe that blood also splattered the walls, carpet and furniture in the room; an autopsy listed among Propp's injuries a broken nose and a brain hemorrhage.
The report adds that when a nurse asked Castor what happened, he told her, "If he says one more word, I'm going to kill him."
Castor subsequently met with investigators, and in a later portion of the affidavit cited by 7News, he gave some hint as to what set him off. As he reached for his quilt, he told the agent, "He tried to touch it," adding, "It didn't work out for him too well."
As he made this last statement, the report goes on, Castor allegedly made what's characterized as "a slight striking gesture with his hands" and added the comment, "Fourteen times."
If this statement indicates Castor understood what happened, at least at that moment, other information in the affidavit gives an indication of how the disease has diminished him. His wife told investigators that he was in the sixth stage of Alzheimer's and would "urinate in a waste basket in his room and put his dirty adult diaper in his dresser."
She also quoted Castor as telling her Propp had struck him in the past, but that account has not been confirmed.
At first, Castor was arrested on charges of second-degree assault. But when Propp died Monday morning, a homicide allegation was added to the roster.
Another court appearance is likely in the offing for Castor — but there remain doubts that he will be found competent to stand trial. Pam Russell of the First Judicial District DA's office notes that he will undergo an evaluation at the state mental hospital in Pueblo.
In the meantime, we offer our sincere condolences to the friends, family and loved ones of Gerald Propp.
Here are two reports about the case — the first from CBS4, the second from 7News.
Send your story tips to the author, Michael Roberts.