Posted on behalf of Heidi Ledford
A test that looks for Alzheimer’s-associated proteins in spinal fluid may hold the key to early diagnosis of the troubling disease, according to a report published today in Archives of Neurology.
Alzheimer’s disease is usually diagnosed using memory tests that only catch the disease when it has become fairly advanced. Some say, however, that future Alzheimer’s disease therapies are most likely to succeed if they were used during earlier stages of the disease, perhaps even a decade before it can be diagnosed using current techniques.
The new test assays two proteins, beta-amyloid and tau. In an initial study of over 400 people, the method identified 90% of the 102 study participants who had Alzheimer’s disease. The test also flagged 75% of the 200 participants with memory problems referred to as ‘mild cognitive impairment’, and a surprising 36% of the remainder, who had seemingly healthy memories. Those among the 36% were nearly 7-times more likely to carry a version of the APOE gene that is associated with increased risk of Alzheimer’s.
In a follow-up study, the researchers – members of the Alzheimer’s Disease Neuroimaging Initiative – tested 57 additional patients with mild cognitive impairment, and identified all of those who went on to develop Alzheimer’s disease in the next five years.
The results need to be replicated in additional studies, but do raise hopes that a relatively simple clinical test could be used to catch the disease early. Nevertheless, the test still faces many challenges, not all of them scientific, cautions Zara Herskovits of the Brigham and Women’s Hospital, Boston and John Growdon of the Massachusetts General Hospital in a related commentary. The general population tends to become a bit queasy at the thought of a spinal tap, they note, and patient education will be needed to ease those fears. And of course there is the perennial question: with no effective treatment or preventative yet available for the disease, would you necessarily want to know your status?
Image: Sue Clark via Flickr, some rights reserved.