If you are worried that you are becoming more forgetful with age, chances are good that’s actually a positive sign.
Slower reaction times and longer delays in information retrieval are a normal part of aging, especially as adults enter their 50s. This might mean forgetting people’s names or forgetting where the car is parked.
But according to new research from Toronto’s Centre for Addiction and Mental Health (CAMH), when people are aware that they are having problems with memory, this actually represents lower risk for progression to from mild cognitive impairment (MCI) to dementia or Alzheimer’s.
MCI falls somewhere between the expected memory decline with aging and the more serious memory decline of dementia. Sometimes MCI progresses to Alzheimer’s, but in other cases MCI is stable or can even improve with time.
People with MCI can vary along the spectrum of how aware they are of their memory decline. There are the people who recognize the signs and seek help, and then there are the people who are blissfully unaware and need to be brought in by an insistent friend or family member who notices.
And being unaware of memory loss is a medical condition that has a name: anosognosia.
The study looked at 1,062 people aged 55 to 90, including 191 with Alzheimer’s, 499 with MCI, and 372 who were healthy controls. The study participants were scored using standard cognition tests for memory loss, and PET brain scans were taken to look at brain metabolism.
Brain cells need to metabolize glucose, a simple sugar, to get the energy needed to function. The brain scans showed decreased glucose metabolism in Alzheimer’s patients. They also showed reduced glucose metabolism in specific brain regions in patients with both MCI and anosognosia.
MCI patients who also have anosognosia are more likely to progress to Alzheimer’s. The researchers believe the combination of memory loss in MCI and the changes in brain metabolism that come with anosognosia predict more severe future decline in brain function.
By contrast, MCI alone predicts that patients will not progress to Alzheimer’s. However, this does not rule out any number of other factors that might be causing memory loss, and further investigation could point to a treatable cause.
There is currently no definitive test for Alzheimer’s in living patients, and because the most promising drugs in clinical trials work best in earlier stages of the disease, the race is on to find ways to identify Alzheimer’s patients sooner. Measuring awareness of memory loss may prove a useful tool to make this diagnosis.
