At a Glance:
- Alzheimer’s disease is not just one disorder with one specific set of symptoms
- Studies show other disorders, such as frontotemporal dementia and mild cognitive impairment, show similar symptoms but affect different parts of the brain than Alzheimer’s
- Research is leading to new understanding of cognitive decline, which in turn may identify new targets for therapy and possible prevention
Dementia is a brain disorder that seriously affects a person’s ability to carry out daily activities. The most common form of dementia among older people is Alzheimer’s disease, which initially involves the parts of the brain that control thought, memory and language. As more and more of the brain is affected, areas that control basic life functions, like swallowing and breathing, become irreversibly damaged.
Although scientists are learning more every day, they still do not know what causes Alzheimer’s, and there is no cure. New understanding, improved treatments and viable preventive strategies are becoming ever more crucial: Increasing numbers of people are joining the more than 5 million Americans already living with Alzheimer’s disease, and its prevalence is expected to double by 2020.
More than 400 physicians, nurses, social service workers, caregivers and community members attended the 10th annual Updates on Dementia: Translating Research into Practice, a conference held at Stanford in early June that featured experts in clinical research and elder care who covered topics that included sexuality, bathing and hygiene, ethnic and cultural sensitivity, and gay and lesbian issues. The event was moderated by Victor Henderson, MD, MS, a professor of Health Research and Policy and a member of the Stanford Center on Longevity.
“It’s a burgeoning crisis, and if we don’t do anything about it the population curves indicate that tens of millions of people will have it over the next 20 to 30 years,” said Ronald Petersen, MD, PhD, director of the Mayo Clinic Alzheimer’s Disease Research Center, who spoke on Mild Cognitive Impairment: The Current Status. “If we are to have an impact on Alzheimer’s disease, we will need to prevent the whole process. This will require predictive testing before symptoms develop and interventions to slow its progression.”
Petersen’s presentation focused on mild cognitive impairment (MCI), a transitional period between normal function and the onset of Alzheimer’s. This condition does not fit the criteria for dementia because although patients show diminished memory and judgment, most abilities are preserved and normal activities are maintained. The challenge, he said, is that there are no specific tests, and the indices, such as verbal recall, fall into the expected profiles of aging.
Mild cognitive impairment falls into two patterns, he said. Approximately 10 percent of the people with amnesiac MCI, in which memory is affected, develop Alzheimer’s disease, while only 1 to 2 percent of the patients with non-amnesiac MCI-those with no memory impairment but with cognitive complaints-do not go on to acquire the disease.
“We have been tracking patterns of impairment over the years,” Petersen said. “We can measure the degree of shrinkage in the hippocampus. The volume of the brain shows a greater degree of atrophy in amnesiac MCI. By documenting serial progression using magnetic resonance imaging, we may be able to use and track disease-modifying therapies.”
Petersen also discussed the potential of using biomarkers, including proteins such as amyloids and apo-E, to study the patterns of impairment.
“Is MCI just early Alzheimer’s? Not always, and it’s still too soon to be sure of the connections,” he said. “Our future progress will depend on getting a diagnosis earlier so we can figure out ways to intervene or at least delay onset or prolong the transitional stage. There are lots of variabilities in the studies and, in the meantime, we must reassess the criteria.”
Research is showing that Alzheimer’s is just one disease related to cognitive decline, according to Bruce Miller, MD, director of the Memory and Aging Center at UCSF, who spoke on Frontotemporal Dementia and Other Non-AD Dementia.
Frontotemporal dementia (FTD) refers to a group of diseases that are commonly misdiagnosed as Alzheimer’s-an important distinction because these diseases are treated differently. Patients with FTD have different behaviors early on that appear to last longer.
The symptoms of FTD include apathy, indifference, repetitive mannerisms and addictive behavior, such as gambling and overeating. These behaviors affect a different part of the brain, making it relatively easy to separate FTD from Alzheimer’s. At the same time, FTD is a social disorder, and input from caregivers is important because its victims have poor self perception. People who are misdiagnosed can end up in the legal system, under psychiatric care or as social pariahs.
“It’s not so much how we label the disease as much as knowing what molecule is responsible,” he said. “These are not pure disorders. They have mixed pathologies, which means that people are starting to think of new ways to intervene. Lots of problems are neurochemical, so I think this is a very promising period.”
Many cognitive disorders relate closely to other disorders: For example, Parkinson’s puts people at high risk for dementia but not necessarily Alzheimer’s, and most Alzheimer’s patients eventually develop symptoms similar to Parkinson’s. And 65 percent of patients with REM (rapid eye movement) sleep behavior disorder, in which the motor system is not turned off during deep sleep, develop some kind of Parkinsonian disorder. These connections all point to potential points of intervention, Miller said.
“The circuitry in the brain is breaking down, but it is the part that affects social behavior and regulation rather than memory,” said Miller. “It’s a social disorder. There is no amyloid accumulation in the brain as you would see in Alzheimer’s disease. This is important because it requires different interventions and the need to monitor and evaluate therapies.”
Other speakers during the day-long conference discussed Love, Sex and Alzheimer’s; Caring for Someone with Dementia when you are Lesbian, Gay, Bisexual or Transsexual; and Bathing Without a Battle. Handouts offered lists of local and national resources, and descriptions of Alzheimer-related clinical trials.
For More Information:
Stanford Geriatric Education Center
Stanford Center of Longevity
Institute on Aging
VA Palo Alto Heath Care System
Geriatric Research, Education and Clinical Center