Mild cognitive impairment - marked by a loss in short-term memory in particular - may be a stronger predictor of Alzheimer's disease than so-called "biomarkers," which include things such as changes in brain volume or levels of certain proteins in cerebrospinal fluid, a new study suggests.
Spanish researchers looked at 116 people with mild cognitive impairment (MCI) who developed Alzheimer's disease within two years, 204 patients with the condition who didn't develop Alzheimer's and 197 people with no cognitive problems.
Mild cognitive impairment is usually marked by difficulties with short-term memory, such as losing your train of thought repeatedly or having trouble remembering what you did yesterday. You may begin to demonstrate uncharacteristically poor judgment or have trouble finding your way around familiar places. Some people may also develop depression or anxiety, or show signs of unusual irritation, aggression or apathy.
People with MCI can generally recall events in the more distant past in detail, however, and are usually able to reason, solve problems and communicate well with others in spite of relatively minor memory loss. In addition, not all cases of MCI progress to Alzheimer's disease.
How the study was done
Cerebrospinal fluid samples were collected from the participants at the start of the study and at annual visits for two years. Blood samples gathered at the start of the study were analysed for genes associated with Alzheimer's, and magnetic resonance imaging (MRI) was used to assess the participants' brain volume and cortical thickness.
The researchers found that two measures of delayed memory, along with the cortical thickness of the left middle temporal lobe in the brain, were associated with a higher risk of mild cognitive impairment developing into Alzheimer's.
Mild cognitive impairment at the start of the study was a stronger predictor of Alzheimer's than most biomarkers, the researchers concluded.
The study appears in the September issue of the Archives of General Psychiatry.
The Alzheimer's Association has more about mild cognitive impairment.
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