What is preclinical Alzheimer disease, and why should we care?

Every 65 seconds someone in the U.S. develops dementia.

Science has not yet delivered meaningful treatments for dementia, but it is delivering on detection of preclinical dementia states (changes that are measurable in the brain but there are no symptoms yet) using biomarkers in spinal fluid and PET brain imaging.  These techniques are used currently only in research settings and may predict dementia decades before full blown symptoms occur. But without treatments, do we (or our prospective caregivers) want to know about a tragic disease that may or may not happen years later?

The Alzheimer’s Association just released its annual Facts and Figures updating the burden of dementia in the U.S., and the burden is enormous, especially for caregivers. Some experts believe we should start testing for preclinical dementia to inform people of their elevated (but not guaranteed) risk of getting dementia. Other professionals find this ethically challenging given the uncertainty about the risk, that we have no treatment and that living with the knowledge of “what if?” could be psychologically devastating.

The idea of preclinical dementia is here to stay and is arguably the most fertile ground for new drug discovery.

Our task, as potential patients, caregivers and providers, will be managing the uncertainty.