at a health care facility but normal cognition on tests. Mild cognitive impairment was defined according to published criteria. These include a decline in memory or another cognitive domain reported by the patient, informant, or both and objectively verified by neuropsychological testing, in combination with no or minimal impairment in activities of daily living and not meeting criteria for dementia.
Accuracy in determining the cause of cognitive loss and subsequent dementia and eliminating false-positive cases in clinical trials evaluating amyloid-related therapeutics require a precise determination of the status of amyloid pathology. Further, therapy for AD requires initiation of treatment in the predementia phase when the neuropathology is limited and regeneration can potentially occur.-- Roger N. Rosenberg, MD
The observation that a substantial number of patients with MCI were not amyloid positive, even at older age,
suggests that the MCI phenotype does not always have AD as underlying pathology. Possible non-AD causes in MCI may be hippocampal sclerosis, mild depression, or vascular damage. Age was a risk factor for amyloid positivity, which is in line with the finding that age is an important risk factor for postmortem amyloid load and for AD-type dementia, as also shown in Figure 4A (above). The prevalence of amyloid positivity in participants with normal cognition aged 50 to 60 years was somewhat higher than found in an earlier population based
study that was not included in our analysis.