We are all Becoming Demented

For the first time since 1984 there is a new clinical diagnostic criteria for Alzheimer's disease dementia.  Published in April 19, 2011 in Alzheimer's & Dementia: The National Institute on Aging working with the Alzheimer's Association have expanded what we now consider  dementia.

While the previous guidelines only recognized one stage—Alzheimer’s dementia—the new guidelines propose that Alzheimer’s disease progresses on a continuum with three stages—an early, preclinical stage with no symptoms; a middle stage of mild cognitive impairment (MCI); and a final stage of Alzheimer’s dementia.  

These new guidelines forge a solid causal link. What was before just a probability of association is now seen as a causal progression from changes in the  brain that have no symptoms, to mild problems with thinking and memory and ending with dementia.

What made this possible is the introduction of new tests that can measure the health of the brain while the person is still alive. In the past, the only way to get a definitive prognosis of dementia was through an autopsy. Nowadays, especially with functional magnetic resonance imagery, the use of biomarkers makes it possible to measure changes in the brain before any symptoms appear, hence the new guidelines.

This ushers in a new era of fatalism. Unintentionally, these new guidelines are stoking the fear of dementia.  A MetLife Foundation study in 2010 reported that people over 55 dread getting Alzheimer’s more than any other disease--other then cancer. These new guidelines raises our sensitivity to subtler decline in thinking and memory. However it is important to stress that this linear connection is not as clear-cut as neuroscientists would have us admit.

MCI indicate difficulty with memory and thinking that are not normal but still allow the individual to  function independently. Many--but not all--people with MCI progress to Alzheimer’s dementia. However there are some important causes of MCI other than dementia--which the guidelines do not address--including medications, stroke or depression.

There are other inconsistencies in the logic of this causal path. As far back as thirty years ago M Marcel Mesulam with Northwestern University, reported 6 patients with progressive word-finding and naming difficulties that worsened over the years, but who did not develop a more generalized dementia.  Even if the connection between MCI and dementia is established, Mike Martin and his colleagues from Zurich, reported the results from their meta-analysis and concluded that cognitive interventions do lead to modest performance gains with older adults.

Even if the brain starts has the neuropathology it does not dictate the behavior. In the famous "Nuns Study" David Snowdon first reported this very strange anomaly. He found that a third of the nuns who behaved and acted free from dementia, were found to have the disease of Alzheimer’s during autopsy. Numerous studies have also found this lack of correlation between the disease and the behavior. More recently, Archana Balasubramanian with colleagues at UCLA reported that for 58 individuals, 90 years and older--who did not have any signs of dementia during three years prior to their death--at autopsy had evidence of the disease of dementia. All these studies erode the direct linear link between the disease and the behavior. There seems to be other mediating factors that the NIA guidelines need to address.

Mario Garrett, Ph.D., is a professor of gerontology at San Diego State University and can be reached at mariusgarrett@yahoo.com

Smell and Dementia

The sense of smell is accomplished through our olfactory system, which is an old system in our biological development. It is also one of the most evocative.

Smell acts as a portal to our emotions. It transports us directly to another time, another place and the only other medium that does this so quickly is the auditory sense--through music. But unlike music-- which can be written down and transferred in what Karl Popper calls World 3--smell is ephemeral.

Smell is somewhat undefined. Good, bad, sweet, acrid, then we loose track of translating the subtle smells into language. Smell has its own language and it cannot comfortably be translated into words.

Smell has power, it is evocative and nuanced so that a particular smell can immediately transport us to our first kiss, or the fear of high school, or your first child being born. Visceral and strong emotions which are hidden in the recesses of your mind. Never lost but subdued until dementia starts to erase them.

The olfactory system has a direct path to the brain. With humans, this system starts with the nose and ends a short distance away at the base of our brain. Olfactory receptors, with very thin fibers,  run  from the roof of the nasal cavity through perforations in the skull ending in the olfactory bulbs, which are a pair of swellings underneath the frontal lobes. It is the only sense that has such a direct physical connection to the brain. It is is also the first to be affected with the onset of dementia or Alzheimer’s. When the brain is affected by dementia, the area that deteriorates first is the area that is responsible for smell.

There is currently a patent, by researchers from Columbia University lead by Davangere Devanand, for a test using scents that include cheese, clove, fruit punch, leather, lemon, lilac, lime, menthol, orange, pineapple, smoke and strawberry. Using this test, the clinicians can predict that an individual who cannot recognize three of the ten scents are five times more likely to develop Alzheimer’s. It has also been found to predict Parkinson’s disease as well as certain types of schizophrenia and brain tumors.

Many people who lose their sense of smell also complain that they lose their sense of taste. Smell enhances the information we get from the mouth; salty, sweet, sour, and bitter tastes. Loss of taste might explain why weight loss is also an indication of dementia. It is not the weight loss on its own, but rather the loss of smell, which brings about the loss of appetite and consequently to diminished appetite.

There are some sixty seven medical conditions identified as possibly causing loss of smell--dementia being one of them. Some of these causes are temporary, such as colds, and nasal allergies such as hay fever.  It may also occur due to some medications and localized nasal polyps and tumors. Such factors reduces the odds of making the patent smell test a very reliable indicator in predicting dementia. But for individuals, it is important to notice changes in how well we can smell. So if you are having trouble with smell, check with your physician first to make sure that this is not a temporary condition.

Mario Garrett, Ph.D., is a professor of gerontology at San Diego State University and can be reached at mariusgarrett@yahoo.com

Super Brains and Dementia

We have a lot of evidence showing that the older you get the more problems we start having with our brains. In healthy adults they tend to shrink, and then they become prone to diseases, not excluding our nemesis of Alzheimer’s disease. We always assumed that these changes are fixed.  But then how do we explain exceptional older adults.

Exceptional adults are examples of what is possible, and not what is statistically likely.

When Emily Rogalski from Northwestern University looked at two groups of Chicago-area older adults of 80 years and older with similar education--12 who had exceptional memory, and ten normal older adults--she was not ready for the findings.  Her study reported that the exceptional group not only had sharp memories--as sharp as people 20 to 30 years younger--but she also found that their brains appear younger.  When compared to 50 to 65 year olds, these exceptional older adults had a thicker outer layer of the brain important for memory, attention and other thinking abilities. While in another region deep in the brain, they had thicker anterior cingulate--which is responsible for attention. Not only was there no shrinkage, these exceptional older adults show youthful brains.

Henrikje van Andel-Schipper was the oldest woman in the world when she died at age 115 in 2005. After Gert Holstege, from Groningen University, undertook a post-mortem of her brain he found few signs of Alzheimer's or other diseases. It seems that these exceptional people have escaped the normal effects of aging.

Jessica Evert from Ohio State University and her colleagues support this view. When examining death from heart disease, nonskin cancer, and stroke, 87% of male and 83% of female centenarians that they studied delayed or escaped these diseases.

If we apply the concept of escapers to the brain, then we can say that exceptional older adults escape from damaging their brain.  As far-fetched as this might seem, researchers are now focusing on studying how we might be developing the brain in detrimental ways. Known as negative plasticity—by not exercising the brain, learning things the wrong way and responding to stress—could be  causing the brain to shrink and develop inefficiently. 

Although brain shrinkage is related to aging, we now know it is not fixed and invariable. If the brain shrinks because of trauma that we impose upon it, then we need to start taking better care of our brain. The brain likes to be challenged, to be happy, stress free, fed well and exercised--just like a precious teen.

Mario Garrett, Ph.D., is a professor of gerontology at San Diego State University and can be reached at mariusgarrett@yahoo.com

Highway Brain and the Earthquake Dementia

Our brain changes as we grow older. Changes dictated by the slow shrinking of the brain, creating a widening of the pockets inside the brain. And there are also changes in parts of the brain used for certain tasks.

We are learning more about these changes because of a new technique of seeing into the brain called functional Magnetic Resonance Imaging. The functional part is that we can have people perform an activity while we watch their brain’s activity.

On the whole we witness variable results when we compare older and younger adults. Sometimes there is less activation among older adults, sometimes more activation, and invariable older and younger adults differ in which parts of the brain they use while undergoing the same activity (eg reading.)

The brain is a wonderfully clever but lazy organ. It works as hard as it has to and nothing more. Which is why sometimes it is hard to learn, because we have to persuade it that it has to. Like any precocious teenager, they will do enough to get by. The brain is like that teen.

David Snowdon studies 678 nuns—Catholic members of the School Sisters of Notre Dame—who are 75 to 106 years of age. The nuns undergo extensive testing and when they die, his team examines their brain. It was Snowdon who first reported a very strange anomaly. He found that a third of the nuns who for all intents and purposes acted normally throughout their life, when they performed the autopsy, they found that their brain had the disease of Alzheimer’s. This finding has since been found in other populations, notably in Sweden where otherwise healthy and competent older adults were found to have diseased brains.

The quick answer to this finding is that some people have “cognitive reserve”. Basically they have more brains and so they can afford to loose some to the disease.  But this does not explain why certain occupations—academic, research, engineering and art, occupations that develop your brain—do not protect you from dementia. It seems that the reserve is not just in size but that the reserve need to be in quality—how you develop and grow your brain.

Like a precocious teen, the brain knows of ways of escaping from its many duties. Doing things that we take for granted—like reading for example—the brain develops an interstate of neural pathways that makes it easy for it to accomplish that repetitive task.  What seems to work is when we trick our brain in developing new pathways.

In a 21-year study of older adults, 75 years and older, Robert Katzman and Joe Verghese, found that mental activities like reading books, writing for pleasure, doing crossword puzzles, playing cards as well as playing golf, swimming, bicycling, dancing, walking for exercise and doing housework did not offer any protection against dementia with some important exceptions:  frequent dancing, playing an instrument and playing board games.

Creating new pathways is what works. When disease interferes with the flow of traffic, then having alternate pathways helps divert traffic. This is what seems to be happening and why it is not just the size of the brain but the networks that we develop that protect us from dementia.

Mario Garrett, Ph.D., is a professor of gerontology at San Diego State University and can be reached at mariusgarrett@yahoo.com