Image courtesy of the Alzheimer’s Reading Room
Q&A with Dilip Jeste: cognitive decline and Alzheimer’s disease
Every 70 seconds, someone in the United States is diagnosed with Alzheimer’s disease, a progressive neurological affliction that, some experts suggest, will eventually swamp the healthcare system if effective treatments are not found
Last week, the Obama Administration announced a national plan to find solutions by 2025, among them expanded research and clinical trials. Toward that end, researchers at University of California, San Diego School of Medicine have just launched three randomized, double-blind, placebo-controlled clinical trials of new treatments for Alzheimer’s disease and a related disorder called Mild Cognitive Impairment. The trials investigate the purported cognitive beneficial effects of resveratrol, a compound found in red grapes, chocolate and tomatoes, and two drugs that target harmful accumulating plaques in the brain. For more information about the trials or to participate, call 858-246-1300 or email.
That’s the good news. The bad news may be a study earlier this year in the British Medical Journal (BMJ) that suggests cognitive decline may begin earlier than previously thought, about age 45. We asked Dilip Jeste, MD, director of the Stein Institute for Research on Aging and a professor of psychiatry and neurosciences at UC San Diego, when folks should get worried.
Q: Are you surprised at all by the BMJ study’s findings that cognitive abilities measurably decline after the age of 45? Is there any indication the decline might actually start even earlier in life?
A: It’s really not a surprise. Clinical and research experience suggests that, while notable cognitive decline may not be observed until late 50s or early 60s, at least subtle declines in some cognitive functions begin earlier.
For example, mental processing speed starts slowing down as early as age 30. Indeed, if we consider other systems in the body, degenerative changes in the knee cartilage appears at age 20.
The news is not all bad, however. For one thing, aging is extremely heterogeneous. Different people age differently, and within the same person, different organs and tissues age at different rates. Similarly, not all cognitive abilities decline with age. Typically, vocabulary does not worsen with age until much later in life. There is also an interesting, not fully understood, but clear and consistent finding that subsequent birth cohorts tend to do better on cognitive tests.
This is known as the “Flynn effect.” Thus, 30-year-olds tested in 2012 will tend to do better on a given cognitive test than 30-year-olds would have done on the same test several decades ago. (This may be, in part, because of improved nutrition and healthcare from younger age in recent birth cohorts.) So, while decline in at least some cognitive domains begins well before “old age,” that rate may now be actually slower than it was in the past.
Q: Everyone at any age can be forgetful or a little fuzzy in their thinking. What would be examples of signs indicating real or serious cognitive decline? Should we be looking for these signs in younger people?
A: This is an important question, and one that our older patients are frequently concerned about: How do we distinguish normal forgetfulness from pathological memory loss or other cognitive decline?
When the deficits are subtle, the only way to be certain about cognitive decline is through repeated cognitive testing with standardized and psychometrically validated measures, which allow one to take into account the normal effects of age, as well as differences attributable to education and other demographic factors.
But in terms of potential warning signs that closer examination might be warranted, there are a couple of points to consider: Things like remembering names of new acquaintances, or where one left the car keys or even minor word finding problems, these happen to all of us, and do tend to get subtly worse with age. But so-called recognition memory tends to be relatively spared. So, if a person finds that he is having considerable difficulty recognizing something that he once knew well, that might be worth discussing with one’s physician. If other people notice that a middle-aged person is having progressive cognitive worsening, it may also be taken as a warning.
Another example of a cognitive ability that tends to be relatively spared with aging is procedural memory – our ability to remember how to do things such as preparing a meal or writing a check or driving a car. When we lose this ability, it can be a sign of trouble, so again would be worth discussing with one’s physician. As to whether physicians should routinely look for these signs in younger people, I do not believe that routine screening is in order. Investigation is needed when the changes are functionally relevant.
Q: How do you slow age-related cognitive decline, especially the little, incremental stuff?
A: We usually think of childhood as the period of growth and development, and old age as the period of deterioration. This view is simplistic. I like to say that aging begins at conception whereas some growth and development continue into old age. The well known adage of “use it or lose it” seems to have some scientific merit. There is growing evidence at both the behavioral and neurobiological levels that an enriched /cognitively stimulating environment can benefit cognitive functioning. People who do daily crossword puzzles, read regularly, have an active social life, appear to be at a somewhat lower (although, unfortunately, not at zero) risk for dementia. So staying mentally engaged is important.
Other things that one can do include controlling cardiovascular risk factors. By controlling blood pressure, watching one’s cholesterol, etc., one can reduce the risk of “micro infarcts” (tiny unnoticed strokes that, cumulatively, may impair cognitive function) as well as major strokes. Exercise, reducing stress to the extent possible, a nutritionally balanced diet can all help with cognitive function.
Risk factors for dementia include a strong family history of Alzheimer’s disease or other dementias, untreated or poorly treated diabetes or hypertension, head injuries. In people with such risk factors, signs of progressive cognitive decline should lead to a consultation with one’s physician.
It is worth noting that stress, anxiety, or depression can worsen cognitive dysfunction. Therefore, these factors should also be considered in management. However, at present, there are no proven “cognitive enhancers” – i.e., drugs that would improve cognition and prevent dementia. The best strategy is healthy lifestyle.