Presented by: Wes Ashford, MD, PhD
Clinical Professor, Psychiatry and Behavioral Sciences (affiliated)
Senior Research Scientist, Stanford/ VA Aging Clinical Research Center
May 19, 2010
- While mild forgetfulness affects most people as they age, serious memory problems affect your ability to participate in everyday activities.
- See your doctor if you have concerns about memory and forgetfulness.
- Alzheimer’s is a type of dementia that progresses slowly over time and causes irreversible changes in the brain.
- Brain imaging for dementia is pointing to specific patterns of amyloid plaque and neurofibrillary fiber build-up in the brain, and these patterns appear to be associated with genetic makeup.
Dementia is a medical condition that impairs memory and thinking processes, from remembering words to how to behave. While everyone forgets words or a person’s name at times, the condition is not dementia unless it is severe enough to interfere with a person’s ability to carry out daily activities and it declines over time.
The most common form of dementia among older people is Alzheimer’s disease, which initially involves the parts of the brain that control memory, and language. The disease was first diagnosed in 1907 in a patient with what are now considered classic symptoms of the disease. Her brain had both senile plaques (filled with a protein called beta-amyloid) and neurofibrillary tangles (made up of tau protein) that affected specific regions of the brain.
The cognitive decline associated with dementia and Alzheimer’s disease is an issue not only for affected individuals but also for society. New understanding, improved treatments, and viable preventive strategies are becoming more crucial since more than 5 million Americans are already living with Alzheimer’s disease, and its prevalence is expected to double by 2020.
“The problem is that it is difficult to recognize when people have a problem,” said Wes Ashford, MD. PhD, a clinical professor of psychiatry and behavioral sciences, at a presentation sponsored by the Stanford Health Library. “People with a memory problem often try to cover it up, and as much as 90 percent of patients are misdiagnosed early in the disease course. After a certain point they don’t recognize that they have a memory problem and by then they need to be in a nursing home.”
Ashford has spent his career researching the process of memory loss associated with aging. He and the other members of the group at the Stanford/VA Aging Clinical Research Center are involved in a variety of studies to measure the effectiveness of medications, mood, sleep, and other factors on disease progression. He has developed a simple memory test that can help track changes over time, using colorful images to detect early signs of memory loss.
Ashford explained that the brain is constantly creating new connections among its billions of neurons as it registers new information. As dementia progresses, the brain no longer maintains this neural network, affecting first short-term memory and then older, more established connections. Brain autopsies show that the hippocampus, the part of the brain involved in forming and maintaining memories, shrinks dramatically and becomes riddled with amyloid plaques and neurofibrillary tangles.
“Plaques and tangles occur in very specific areas of the brain that are responsible for learning and storing new information,” Ashford said, adding that plaques appear to be associated with Alzheimer’s disease, while tangles show a closer relationship with the dementia that accompanies Alzheimer’s in its later phases. “The disease progresses in a variable but measurable fashion, following a specific pattern. It may progress slowly but it tracks logically, and eventually old memories become destroyed.”
By using different imaging technologies, such as MRI, PET, and CT scans, scientists have been able to follow the progression of dementia and Alzheimer’s, and found that genetic factors play a significant role the age when patients develop brain patterns associated with amyloid plaques and with neurofibrillary tangles.
“We can actually see where the tangle develops and where the amyloid is depositing,” said Ashford. “We can track progression over time while it is still considered mild cognitive impairment, before it is officially dementia.”
For one common genotype (20 percent of the population), there is a 40 percent chance of developing Alzheimer’s by age 76; another genotype (one that affects only 2 percent of the population) has 10 times greater chance of having the disease by age 67; another group appears to develop Alzheimer’s only after age 95.
For Ashford, these studies may help to measure the early progression of disease and then identify a way to prevent its development in the people who would most benefit from intervention. Though a genetic approach to prevention is not on the immediate horizon, these studies do point to the possibility of targeted interventions based on genotype.
“If we can understand the genetics better, we will be able to understand how Alzheimer’s develops and the best method and timing to make changes,” he said. “To make progress we need diagnostic and treatment centers for humans and accessible genetic testing.”
In the meantime, other factors have been shown to decrease the risk of Alzheimer’s, such as maintaining a healthy lifestyle, interacting with others through social activities, keeping the brain exercised through games and learning, and keeping up with screening tests for high blood pressure and cholesterol.
About the Speaker
J. Wesson Ashford, MD, PhD, is a senior research scientist at the Stanford/Veterans Affairs Aging Clinical Research Center and a clinical professor of Psychiatry and Behavioral Sciences at Stanford. He is also the director of the War Related Illness and Injury Study Center at the VA Palo Alto Health Care System. Ashford received his MD and his PhD in neuroscience from UCLA, where he was a founding member of the Neurobehavior Clinic and the first chief resident and associate director on the Geriatric Psychiatry Inpatient Unit. He joined Stanford and the VA Palo Alto in 2003.
For More Information:
Stanford / Veterans Affairs Aging Clinical Research Center
Dr. Ashford’s online memory test
VA Palo Alto Heath Care System