In fact, it is very difficult for caregivers and family members to make progress with a person’s illness when a loved one is showing signs of anosognosia. Yet, the condition is alarmingly common: After stroke, some studies show up to 77% of patients suffer anosognosia at least temporarily, reports one review of the literature.
It occurs frequently in those with mental illness, according to the Treatment Advocacy Center, and can also affect people who have suffered traumatic brain injury, as well as people with Alzheimer’s and other types of dementia.
Studies suggest that deterioration in the frontal lobes may be involved, which “play an important role in problem-solving, planning and understanding the context and meaning of experiences and social interactions,” according to the New York Times’ New Old Age blog.
To put it another way, our right brain is wired to detect anomalies and new information and incorporate these into our sense of reality, says the neuroscientist Dr. V.S. Ramachandran, also in the New York Times. When something happens to damage that part of the brain – a stroke or dementia, for instance – then “the left brain seeks to maintain continuity of belief, using denial, rationalization, confabulation and other tricks to keep one’s mental model of the world intact.”