PARIS – Falls occur significantly more often among cognitively normal older adults with evidence of preclinical Alzheimer’s disease on positron emission tomography than among those with no signs of Alzheimer’s, according to findings from an ongoing prospective cohort study.
If the findings hold up, they suggest that falls could prove to be an early signal of the disease, Susan Stark, Ph.D., said at the Alzheimer’s Association International Conference.
Her study involved 119 adults from longitudinal studies of memory and aging at Washington University’s Knight Alzheimer's Disease Research Center in St. Louis who underwent amyloid imaging via Pittsburgh compound-B PET scanning (PIB PET). A total of 18 had a positive scan, indicating amyloid plaque burden in the brain consistent with preclinical Alzheimer’s disease, Dr. Stark reported in a poster.
Of those 18 subjects, 12 (67%) experienced at least one fall during the first 8 months of the study, compared with only 36 of 101 (36%) patients with a negative PIB PET, indicating low amyloid plaque burden. The rate of falls among those in the latter group is about what would be expected among healthy adults in this age group, said Dr. Stark of the occupational therapy program in the department of neurology at Washington University.
Participants had a mean age of 74.5 years, were mostly female (64%), and reported falls monthly by mail. All underwent clinical evaluation and a PET scan with PIB PET. They also provided cerebrospinal fluid for biomarker analysis.
The findings point to the importance of understanding not only the cognitive impairments associated with Alzheimer’s disease but also the motor changes that appear to precede cognitive changes, Dr. Stark noted.
In a written statement highlighting the research, Maria Carrillo, Ph.D., agreed that the findings "illustrate the significance of understanding that, in some people, changes in gait and balance may appear before cognitive impairment."
Evidence increasingly suggests that "silent" biological brain changes may be occurring a decade or more before outward symptoms of Alzheimer’s can be seen, said Dr. Carrillo, senior director of medical and scientific relations for the Alzheimer’s Association.
"According to this study, a fall by an older adult who otherwise has a low risk of falling may signal a need for diagnostic evaluation for Alzheimer’s," she said.
Dr. Stark added that while her study is the first she knows of that has identified a risk of increased falls related to a diagnosis of preclinical Alzheimer’s disease, the findings are consistent with those from previous studies of mobility problems in those with very early symptomatic disease or mild cognitive impairment.
Dr. Carrillo said additional research is urgently needed to further explore the connection between motor deficits and falls as an early sign of disease.
Not only will such research elucidate such connections, it might also help prevent falls and the multiple problems associated with them in older adults, Dr. Carrillo added.
"In the near future, with continued research, we will improve our ability to detect and intervene early in Alzheimer’s disease. With earlier detection, perhaps we can also lower the risk of falls, which can be disabling, expensive, and even deadly in older adults," she said.
This study was funded by the National Institute on Aging. Neither Dr. Stark nor Dr. Carrillo had disclosures to report.