Alzheimer Disease, Biomarkers, and Clinical Symptoms —Quo Vadis?—Reply

In Reply The Letter to the Editor by Montero-Odasso and colleagues addresses noncognitive manifestations of Alzheimer disease (AD). Their letter discusses a recent article from the Mayo Clinic. Using positron emission tomography biomarkers of amyloidosis (A) and tauopathy (T), the Mayo study examined the age- and sex-specific prevalence of 3 biologically defined entities: amyloidosis (A+) regardless of tau status, A+T −, and A+T+. We compared the age and sex specific prevalence of these 3 biomarker-defined entities with 3 clinical syndromes commonly associated with AD: clinically defined probable AD using the McKhann et al criteria, mild cognitive impairment, and dementia. We found that the prevalence of biolog ical AD (defined by the A+T+ biomarker profile) is more prevalent than the classic syndrome of clinically defined probable AD at all ages and roughly 3 times more prevalent at age 85 years in men and women. We attributed this to the fact that brain pathology precedes symptoms by years; thus, many in dividuals who have the disease do not have cognitive impairment.
Source: JAMA Neurology - Category: Neurology Source Type: research