Panel: AD Biomarkers Should Be Reserved for Clinical Trials

Guidelines for the diagnosis of Alzheimer disease and its early companions MCI and preclinical dementia have been revamped for the first time in 27 years, reports the National Institute on Aging (NIA). And a quick scan of the online documents, offered freely at the site of the journal Alzheimer's & Dementia, reveals that a lot of thought and ink has been devoted to the burgeoning area of biomarkers—meaning the use of brain imaging, like MRI or PET, or assays of tell-tale molecules, like beta amyloid and tau, in spinal fluid (CSF).

The overriding admonishment, at least for now, is that these biomarkers aren't ready for routine practice—which is not necessarily something unexpected by practicing neurologists, but which may dampen the otherwise-unbridled enthusiasm of industry (eg, Lilly), venture capitalists, and some journalists. One big caveat offered by the members of the NIA- and Alzheimer's Association-sponsored panel, which revamped the moldy guidelines,* is that there is currently little standardization of these biomarkers to ensure their proper use and interpretation in routine practice. Consequently it is recommended that they be incorporated only into clinical trials and accompany other, conventional measures of the dementing process.

Another thought here is that CSF assays won't really take off in routine practice until somebody invents a quick-and-easy method for obtaining the fluid. As far as I can tell, the bedside/office procedure—which, although generally benign, is still a somewhat clunky process*—hasn't changed in more than 100 years. And much like the guy who (by legend) made money selling mining utensils during the various gold rushes, the guy or gal who revolutionizes our antiquated method for obtaining spinal fluid will profit the most when CSF biomarkers are (probably inevitably) incorporated into routine practice.

MCI = mild cognitive impairment.

* But the fact that the need to change these guidelines hasn't been acutely felt since 1984 shows just how little progress we've made in understanding this illness. Sigh.

** And without significant reimbursement.

Photograph of atrophied brain from person with AD: National Institute on Alcohol Abuse and Alcoholism.