Being Unaware of Memory Loss Tied to Greater Risk for Alzheimer's

Do you find yourself worrying about how poor your memory has been lately? This may actually be a good thing. A new Canadian study published in the Journal of Clinical Psychiatry shows that people who are aware of their memory problems are actually less likely to develop dementia or Alzheimer’s disease.

On the other hand, individuals who are unaware of their memory loss, a condition known as anosognosia, are more likely to develop Alzheimer’s.

“If patients complain of memory problems, but their partner or caregiver isn’t overly concerned, it’s likely that the memory loss is due to other factors, possibly depression or anxiety,” says lead author Dr. Philip Gerretsen, Clinician Scientist in the Centre for Addiction and Mental Health (CAMH) Geriatric Division and Campbell Family Mental Health Research Institute in Toronto.

“They can be reassured that they are unlikely to develop dementia, and the other causes of memory loss should be addressed.”

In more serious cases, however, the partner or caregiver is the one most likely to feel distressed while the patient has no awareness of any memory problems. In Alzheimer’s disease, lack of awareness is associated with more burden on the caregiver. Both unawareness of illness (anosognosia) and memory loss (known as mild cognitive impairment) can be objectively assessed using questionnaires.

The study, which may be the largest of its kind on illness awareness, involved the data of 1,062 people aged 55 to 90 from the Alzheimer’s Disease Neuroimaging Initiative (ADNI). This included 191 people with Alzheimer’s disease, 499 with mild cognitive impairment and 372 as part of the healthy comparison group.

The researchers also wanted to know which regions of the brain are impacted when a patient is unaware of his or her illness. To do this, they examined the brain’s uptake of glucose, a type of sugar. Brain cells need glucose to function, but glucose uptake is impaired in Alzheimer’s disease.

Using PET (positron emission tomography) brain scans, the research team showed that those with impaired illness awareness also had reduced glucose uptake in specific brain regions, even when accounting for other factors typically associated with a decrease in glucose uptake, such as age and degree of memory loss.

In the next stage of this research, Gerretsen will be tracking older adults with mild cognitive impairment who are receiving an intervention to prevent Alzheimer’s dementia. This ongoing study, known as the PACt-MD study, combines brain training exercises and brain stimulation with a mild electrical current to improve learning and memory.

Source: Centre for Addiction and Mental Health