Falls are more common among individuals with the earliest signs of Alzheimer's, according to a study presented at the Alzheimer's Association® International Conference.
The study measured the rate of falls among cognitively healthy older adults with and without preclinical Alzheimer's – as measured by amyloid imaging using positron emission tomography (PET) with Pittsburgh compound B (PiB) – and found twice the risk of falls for people with higher levels of PiB on their scan.
In older adults, falls contribute to increased disability, premature nursing home placement and injury-related mortality. There are also higher health care costs associated with falls – more than $19 billion could be attributed to the direct medical costs of falls in 2000.
Older adults with Alzheimer's may be at higher risk for falls because of balance and gait disorders and problems with visual and spatial perception that are caused by the disease.
"Understanding the traditional hallmarks of Alzheimer's, including cognitive impairment and memory loss, are important; however, these study results also illustrate the significance of understanding that, in some people, changes in gait and balance may appear before cognitive impairment," said Maria Carrillo, PhD, Alzheimer's Association Senior Director of Medical and Scientific Relations.
"Growing scientific evidence suggests that 'silent' biological changes may be occurring in the brain a decade or more before we can see the outward symptoms of Alzheimer's. 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," continued Carrillo.
Led by Susan Stark, PhD, Assistant Professor of Occupational Therapy and Neurology at Washington University in St. Louis, the 8-month study followed 125 older adults currently enrolled in longitudinal studies of memory and aging at Washington University's federally funded Knight Alzheimer's Disease Research Center (ADRC). All participants had PiB PET imaging and contributed samples of cerebrospinal fluid (CSF). Each participant was asked to record in a journal how many times they experienced a fall, which was defined as unintentional movement to the floor, ground or an object below knee level. Some of participants had preclinical Alzheimer's and some did not. With an average of 191 days of data collected for participants, the study found that 48 people experienced at least one fall. A positive PiB PET image resulted in a 2.7 times greater risk of a fall for each unit of increase on their PiB PET scan.
"To our knowledge, this is the first study to identify a risk of increased falls related to a diagnosis of preclinical Alzheimer's disease," said Stark. "This finding is consistent with previous studies of mobility problems among persons with very early symptomatic Alzheimer's or mild cognitive impairment. It suggests that higher rates of falls can occur very early in the disease process."
"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," said Carrillo. "Additional research is urgently needed, for example to further explore the connection between motor deficits and falls as possible early signals of Alzheimer's.
Susan Stark, PhD, et al. Risk of falls among older adults with Preclinical Alzheimer's Disease. (Funders: U.S. National Institute on Aging, the Knight Alzheimer's Disease Research Center at Washington University).
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