A new way of testing for signs of Alzheimer's disease in spinal fluid may more accurately identify which people with mild memory deficits will progress to full-blown dementia.
Researchers reporting in Neurology explained that current spinal fluid tests for Alzheimer’s look for an imbalance in two proteins: the plaque-forming beta amyloid, and tau, which is seen as a marker of brain cell damage.
People with Alzheimer's tend to have lower levels of beta amyloid and higher levels of tau protein in their spinal fluid, and doctors often test for this to confirm the dementia is caused by Alzheimer's.
In the study, Dr. Perneczky and colleagues looked for amyloid precursor proteins (APP).
"Being able to identify who will develop Alzheimer's disease very early in the process will be crucial in the future," said Dr. Robert Perneczky of the Technical University Munich in Germany, who led the study.
"Once we have treatments that could prevent Alzheimer's disease, we could begin to treat very early and hopefully prevent the loss of memory and thinking skills that occurs with this devastating disease."
The researchers collected spinal fluid from 58 people with mild cognitive impairment.
After three years, 21 had developed Alzheimer's, 27 still had mild cognitive impairment, eight had reverted back to their normal cognitive health, and two others had developed frontotemporal dementia and were excluded from the analysis.
The study showed that people who progressed to Alzheimer's had significantly higher levels of soluble amyloid precursor protein beta in their spinal fluid than those who did not develop Alzheimer's.
When combined with other markers, such as the presence of tau and a person's age, the test was roughly 80% accurate in predicting whether the disease would develop.
The researchers also found that the form of beta amyloid normally used to test for Alzheimer's was not a good predictor of which patients with mild impairments might progress to dementia.