Medical Research: What are the main findings of the study?
Dr. Kryscio: We followed 531 elderly over time assessing their cognition annually; of these 105 (about 20%) eventually were diagnosed with a serious cognitive impairment (either a mild cognitive impairment or a dementia) and 77% of the latter declared a subjective memory complaint prior to the diagnosis of the impairment. In brief, declaration of a memory problem put a subject at three times the risk of a future impairment.
Medical Research: What was most surprising about the results?
Dr. Kryscio: There were two surprising findings:
The time intervals involved: Average age at enrollment was 72 and it took on average until age 82 for the subject complaint to occur.
It took on average 6-9 years for a mild cognitive impairment diagnosis and 6-16 years on average for a dementia to occur.
A large proportion of the complainers died without an impairment (127 of 296 or 43%) and most of these came to autopsy which revealed Alzheimer’s pathology (increase neuritic plaques) in key brain regions when compared to noncomplainers who died without an impairment and came to autopsy.
Medical Research: What should clinicians and patients take away from your report?
Dr. Kryscio: Self-reported memory complaints are common among the elderly (56% in our cohort) but there is considerable time before any serious event will happen and it may never happen.
Hence, elderly with a complaint should not panic but should see their doctor and then jointly they should monitor cognition going forward to see if cognition is truly declining.
Medical Research: What recommendations do you have for future research as a result of this study?
Dr. Kryscio: We are examining the change in cognition at the time of the compliant. If we are successful in developing a simple way to determine who will progress, we will have a high risk group for future prevention studies.
Unfortunately, while we have time between the complaint and the impairment, we do not have an effective intervention to ward off the disease yet.
Self-reported memory complaints
Implications from a longitudinal cohort with autopsies
Richard J. Kryscio, PhD, Erin L. Abner, PhD, Gregory E. Cooper, MD, PhD, David W. Fardo, PhD, Gregory A. Jicha, MD, PhD, Peter T. Nelson, MD, PhD, Charles D. Smith, MD, Linda J. Van Eldik, PhD, Lijie Wan and Frederick A. Schmitt, PhD
Published online before print September 24, 2014, doi: 10.1212/WNL.0000000000000856 Neurology 10.1212/WNL.0000000000000856