Anosognosia is a neuropsychological disorder defined by an individual’s lack of awareness of his own disease or the loss of functional capacity from which he suffers. The term is derived from Greek and associates nosos (disease) and gnosia (knowledge), described by Babinski in 1914.
It was associated in the 1980s with dementia in general and Alzheimer’s disease in particular. In this case, anosognosia is the inability to recognize the presence of a deficit or to appreciate its severity.
Anosognosia is therefore common in patients with Alzheimer’s disease or other types of dementia.
It is a cause of difficulty in taking care of and increasing the caregiver’s burden.
It is mainly reflected by a loss of awareness of their deficit in instrumental activities of daily life, depressive disorders, and behavioral disorders (hallucinations, delusions)
Patients with anosognosia are more often apathetic.
Anosognosia: a harbinger of Alzheimer’s disease?
Patients who are unaware that they have memory problems are more likely to see their condition worsen in a short period of time and develop Alzheimer’s disease.
Certain brain conditions can interfere with a patient’s ability to understand that they have a health condition. Anosognosia, which is often associated with Alzheimer’s disease, is a neurological disorder that affects a patient’s ability to realize they have a health condition.
A study published by a Canadian team (McGill University) found that people who were unaware of their condition had almost three times the likelihood of developing dementia within two years.
Anosognosia would therefore be a new identified precursor sign of Alzheimer’s disease.
The researchers analyzed 450 patients who had mild memory deficits but were still able to take care of themselves.
The researchers asked them and their relatives to assess their cognitive abilities.
When a patient self-reported no cognitive issues but a family member reported significant difficulties, the patient was considered unaware of their condition.
The researchers then compared the anosognosia group to those who had no problems with consciousness and found that the anosognosia group had impaired brain metabolic function (neurons were less active) and increased amyloid deposits.
Two years later, a follow-up showed that patients who were unaware of their memory problems were more likely to have developed dementia, even when controlling for other factors such as genetic risk, age, sex and gender, and education.
The increased progression to dementia coincides with a decline in brain metabolism in regions affected by Alzheimer’s disease (particularly the hippocampus)
This discovery highlights the importance of consulting the patient’s close family members during medical visits.
“According to Dr. Serge Gauthier, professor of neurology at McGill University, people with mild memory impairment should have an assessment that takes into account information gathered from reliable informants, such as family members or close friends.
Source J. Therriault et al. Anosognosia predicts default mode network hypometabolism and clinical progression to dementia. Neurology, 2018.