- What factors are associated with the reduction of risk of Alzheimer's disease?
- What factors are associated with the reduction of risk of cognitive decline in older adults?
- What are the therapeutic and adverse effects of interventions to delay the onset of Alzheimer's disease? Are there differences in outcomes among identifiable subgroups?
- What are the therapeutic and adverse effects of interventions to improve or maintain cognitive ability or function? Are there differences in outcomes among identifiable subgroups?
- What are the relationships between the factors that affect Alzheimer's disease and the factors that affect cognitive decline?
- If recommendations for interventions cannot be made currently, what studies need to be done that could provide the quality and strength of evidence necessary to make such recommendations to individuals?
Below are some of the highlights of today’s presentations and discussions.
Alzheimer’s - syndrome or pathology?
Some researchers use the term Alzheimer’s to refer to Alzheimer’s pathologies (plaques and tangles) but also to a set of symptoms which, at least in old age, is commonly caused by a number of pathologies. This can be confusing, at least to laypeople. One person in the audience asked if, now that we know there are more than just two proteins [beta amyloid and tau] involved, it would be better to go back to the old term “senile dementia” to describe the symptoms.
Normal aging vs. mild Alzheimer’s – can we tell the difference?
The conference was organized to address both Alzheimer’s disease and general cognitive decline. In fact, several presenters said it’s hard to distinguish between the two, at least between normal aging and mild Alzheimer’s. There is a significant decline in people’s ability to remember things by the time they reach middle age, but there is an enormous variation from person to person, even in the absence of disease of any type. So some older people perform at levels more typical of younger adults. Several presenters mentioned their hopes that biomarkers will eventually help determine who has a disease and is at risk for developing dementia. But at least one said age-related cognitive decline might be the same thing as dementia, with the only difference being the degree of pathology and symptoms.
Early is better
Both Alzheimer’s disease and cognitive decline probably have multiple causes and involve multiple pathologies, presenters said. Researchers need to study people over the course of their lifetimes, perhaps from birth, to disentangle those multiple factors and develop preventive measures, or “interventions.” Early diagnosis and treatment will probably be more effective. But the earlier you move diagnosis, the higher the chance of misdiagnosis, especially because existing tests are limited. And because there are currently no disease-modifying treatments, early diagnosis may not be helpful, and has social and insurance implications.Possible interventions
Several presentations focused on the evidence for possible interventions to prevent cognitive decline or Alzheimer’s including:
- Exercise - may prevent cognitive decline, maybe even after Alzheimer’s has developed
- Nutritional supplements such as Vitamin E, Omega-3 fish oils, and B vitamins - may be helpful, but maybe only when there is a deficiency. More research is needed to see whether the U.S. program of folic acid supplementation is bad for memory and thinking
- Alternative treatments – so far, there is no evidence that they work, and there is some evidence that many don’t actually get to the brain.
- “Cognitive engagement” - protective, but it’s not clear why.
- Treating vascular risk factors such as high blood pressure or high cholesterol – the evidence isn’t clear on this
- Treating depression – the evidence isn’t clear on this either, perhaps because there are different types of depression.
- Combinations of interventions – will probably work best, but this type of study is just starting.
You can find out more about the conference and listen in tomorrow or Wednesday at http://consensus.nih.gov/2010/alz.htm.