The project - conducted by researchers at the University of Pittsburgh, University of Illinois, Rice University, and Ohio State University - is considered the first study of its kind focusing on older adults who are already experiencing atrophy of the hippocampus, the brain structure involved in all forms of memory formation. The study, funded through the National Institute on Aging, appears in the Jan. 31 Proceedings of the National Academy of Sciences (PNAS).
The scientists recruited 120 sedentary older people without dementia and randomly placed them in one of two groups - those who began an exercise regimen of walking around a track for 40 minutes a day, three days a week, or those limited to stretching and toning exercises. Magnetic resonance images were collected before the intervention, after six months, and at the end of the one-year study.
The aerobic exercise group demonstrated an increase in volume of the left and right hippocampus of 2.12 percent and 1.97 percent, respectively. The same regions of the brain in those who did stretching exercises decreased in volume by 1.40 and 1.43 percent, respectively.
Spatial memory tests were conducted for all participants at the three intervals. Those in the aerobic exercise group showed improved memory function, when measured against their performance at the start of the study, an improvement associated with the increased size of the hippocampus. The authors also examined several biomarkers associated with brain health, including brain-derived neurotrophic factor (BDNF), a small molecule that is involved in learning and memory. They found that the increases in hippocampal size were associated with increased amounts of BDNF.
"We think of the atrophy of the hippocampus in later life as almost inevitable," said Kirk Erickson, professor of psychology at the University of Pittsburgh and the paper's lead author. "But we've shown that even moderate exercise for one year can increase the size of that structure. The brain at that stage remains modifiable."
"The results of our study are particularly interesting in that they suggest that even modest amounts of exercise by sedentary older adults can lead to substantial improvements in memory and brain health," said Art Kramer, director of the Beckman Institute at the University of Illinois and the senior author.
"Such improvements have important implications for the health of our citizens and the expanding population of older adults worldwide."
Source: University of Illinois at Urbana-Champaign
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today
On Thursday, the panel voted 16 to 0 to recommend approval of the imaging agent, known as Amyvid, with one critical caveat: Manufacturer Eli Lilly and Co. must demonstrate that standards for interpreting brain scans that show amyloid plaques illuminated by Amyvid can be made consistent enough to routinely guarantee an accurate diagnosis.
Amyvid (florbetapir) is injected into patients who then undergo a PET scan; a negative result can help rule out Alzheimer's, according to Lilly.
Experts agreed that the test could become a critical part of spotting Alzheimer's before symptoms have taken hold, but they noted that the clinical reality of that is far from imminent.
"It may well be that amyloid imaging will join colonoscopy, mammography, etc. as mid-life surveillance tests, and that anti-amyloid interventions are most effective in the pre-symptomatic stages of Alzheimer's disease," said Dr. Sam Gandy, the Mount Sinai Chair in Alzheimer's Disease Research in New York City. However, this possibility is years away, he added.
The value for research is clear, Gandy said. "Either a spinal fluid amyloid test or an amyloid scan will help weed out non-Alzheimer's dementias in clinical trials of anti-amyloid agents. The clinical value in the short-term is less obvious."
Current medications are most effective in the early stages of Alzheimer's, and amyloid scans might identify those patients for doctors who don't have access to neuropsychological testing, Gandy said.
"A confirmed diagnosis would enable planning for the future while patients are at an early enough stage to still participate in the discussion," he said. "In the symptomatic patient, the amyloid scan would portend the onset of dementia within the next five years."
However, because there is no cure for Alzheimer's disease yet, the test might be one that is not considered worth its cost, Gandy said.
Gandy noted that the "300-pound gorilla in the room" is whether Medicare/Medicaid will reimburse such a test, even if the FDA follows its expert panel's advice and approves Amyvid. (While the FDA doesn't have to follow a panel's advice, it usually does.) "Medicare may decide that the added value does not merit reimbursement without a meaningful intervention," he said.
Also, Grandy said he doesn't expect approval until there are methods in place to train doctors in how to read these scans.
Another expert, David Loewenstein, a professor of psychiatry and behavioral sciences and neurology at the University of Miami Miller School of Medicine, said that the approval of Amyvid "will allow physicians to come to an earlier diagnosis of Alzheimer's."
What is needed is consistency for evaluating scans using the agent, he said, so that physicians "can apply a single standard and there won't be gaps between hospitals because of different readers using different methods."
Loewenstein thinks use of this new diagnostic tool will help in several ways. First, it will help researchers find effective treatments by diagnosing the disease early, although having the plaques does not always mean the patient has Alzheimer's. Second, it will identify people who can take part in clinical trials of new Alzheimer's drugs.
"There is a whole new line of drugs being formulated that will help treat the earliest stages of the disease," Loewenstein said. "We need to know who are the appropriate people with the mildest cognitive problems to get into clinical trials."
In addition, the test has value even before treatments are available in terms of helping patients prepare for the course of the disease, Loewenstein noted. "I think many people would like an early diagnosis," he said.
For more information on Alzheimer's disease, visit the Alzheimer's Association.
Currently, there is no cure for Alzheimer's. But drug and non-drug treatments may help with both cognitive and behavioral symptoms.
Researchers are looking for new treatments to alter the course of the disease and improve the quality of life for people with dementia.
In this section:
- CareFamily and Seniorcorp Offer New Choices for Care to Hampton Roads Seniors
- Recent Articles on Aging and Caregiving
- What is Long-Term Care Insurance?
- New "Generation Alzheimer's" Report Calls Alzheimer's Defining Disease Of The Baby Boomers
- End-Of-Life Decisions Delayed If Patient's Wishes Not Shared With Family
- An Extra 5 Years Of Life An Unexpected Benefit Of Osteoporosis Treatment
- Improvements In Memory In Older Adults Following Moderate Aerobic Exercise
- Alzheimer's Scan Might Help Spot Disease
- AHRQ News And Numbers: Approximately Five Percent Of Seniors Report One Or More Cognitive Disorders
- About Alzheimer's disease