People with this illness don’t know they have it, They don’t understand that anything is wrong. This little-known yet common consequence of this kind of dementia, Alzheimer’s disease and other brain disorders is called anosognosia, and it leaves people unaware that they are compromised by illness.
Imagine someone who survives a stroke and is paralyzed on the left side of his body, but is convinced he can walk without assistance. A less extreme example: Someone with moderate memory deficiency gets lost on the road or has accidents, but thinks she is driving just as well as ever.
This is not denial, said Sandra Weintraub, a professor of psychiatry and neurology at Northwestern University. “It’s a lack of insight and awareness,” she said. “Everyone else around them is aware they’re not the same, and they are not.”
Sometimes anosognosia is selective: An aging parent may realize she has a problem with one kind of activity but is oblivious to other difficulties. But in other cases, the lack of self-awareness is more extensive. According to some estimates, up to 42 percent of people with early Alzheimer’s disease have symptoms of anosognosia. And as dementia progresses, the symptoms also advance, evidence suggests.
Trying to make someone with this problem understand that they have changed and need to accept new limits often is an exercise in frustration, Dr. Weintraub said. Reasoning and evidence make little difference to these patients.
Brain studies suggest that the lack of awareness may be linked to the deterioration of the frontal lobes, especially on the right side, which play an important role in problem-solving, planning, and understanding the context and meaning of experiences and social interactions. Some studies also point to atrophy in the temporal lobes.