Falls are more common in people with the earliest signs of Alzheimer’s Disease, according to new research from the US presented at a conference in Paris at the weekend, where delegates learned how cognitively healthy older adults with and without preclinical Alzheimer’s had twice the risk of falls if PET scans of their brains showed signs of beta-amyloid plaques, one of the hallmarks of the disease. The researchers said this needed further investigation.

The study was presented on Sunday at the Alzheimer’s Association International Conference 2011 (AAIC 2011) which is taking place in Paris and runs from 16 to 20 July.

People with Alzheimer’s Disease have problems with visual and spatial perception; people with such problems are at higher risk of falls.

Estimates suggest the direct health care costs attributed to falls comes to more than $19 billion in the US, where falls also contribute to increased disability, loss of mobility, premature admission to nursing homes, and injury-related deaths.

Study leader, Dr Susan Stark, Assistant Professor of Occupational Therapy and Neurology at Washington University in St Louis, Missouri, told the press that:

“To our knowledge, this is the first study to identify a risk of increased falls related to a diagnosis of preclinical Alzheimer’s disease.”

She said their findings were consistent with previous investigations of mobility problems among people with very early symptoms of Alzheimer’s or mild cognitive impairment, and suggests that falling more frequently can be happening at quite an early stage of the disease.

For their study, Stark and colleagues used a new diagnostic technique called positron emission tomography (PET) with Pittsburgh compound B (PiB) to look for signs of beta-amyloid plaques in brain tissue. Beta-amyloid plaques is one of the characteristic deposits found in the brains of patients with Alzheimer’s disease.

They followed 125 older adults, some with preclinical Alzheimer’s, who were already taking part in studies of memory and aging at the federally funded Knight Alzheimer’s Disease Research Center (ADRC) at Washington University.

All the participants underwent PiB PET scans and gave samples of cerebrospinal fluid. They were also asked to keep a journal, noting how often they fell.

For the purpose of this study, the researchers defined a fall as an “unintentional movement to the floor, ground or an object below knee level”.

The researchers amassed an average of 191 days of data, during which time 48 participants experienced at least one fall.

When they compared the fall incident records with the imaging results, they found if a participant had a positive PiB PET image, there was a 2.7 times greater risk of a fall for each unit of increase on the scan.

The researchers suggested more studies be done to investigate more closely the link between falls and early Alzheimer’s.

Dr Maria Carrillo, Senior Director of Medical and Scientific Relations at the Alzheimer’s Association, agreed, saying further studies could, for example, examine the link between motor deficits and falls as possible early signs of Alzheimer’s.

“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 Carrillo.

She went on to explain how there is a growing body of evidence suggesting that “silent” biological changes may be taking place in the brain of people with Alzheimer’s ten years or more before outward symptoms start to appear.

“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,” said Carrillo, adding that “With earlier detection, perhaps we can also lower the risk of falls, which can be disabling, expensive and even deadly in older adults”.

“In the near future, with continued research, we will improve our ability to detect and intervene early in Alzheimer’s disease,” she noted.

“Risk of falls among older adults with Preclinical Alzheimer’s Disease.”
Susan Stark, et al..
Funded by: US National Institute on Aging, the Knight Alzheimer’s Disease Research Center at Washington University.
Presented Sunday 17 July 2011, at AAIC 2011, Paris, France.

Source: AAIC 2011.

Written by: Catharine Paddock, PhD