Posts Tagged ‘Parasuraman’

What Constitutes Proof that Alzheimer’s or Dementia Could be Cured or Prevented?

January 4, 2017

Two excellent questions for consideration.  The first question, what constitutes a cure can be easily answered, that is the administration of operations or medications that would eliminate the affliction.  Currently, the only medications for Alzheimer’s do not cure the disease, but rather slow the progression.  One can question whether this prolongs meaningful or enjoyable life, or merely prolongs suffering.  This is a question for individuals to decide.
With respect to Alzheimer’s, there are many individuals who died with the defining features of the disease—neurofibrillary tangles and amyloid plaque, but who never exhibited any of the behavioral or cognitive characteristics of the disease.  Apparently there were many people who died not knowing that they had the disease.  So for these individuals, at least, the debilitating features of the disease had been prevented.  The only explanation that has been provided for this prevention is that they had built up a cognitive reserve during their lifetimes, by using their brains.  This is the justification for advocating growth mindsets.  But there are other factors such as being socially active, which also requires the use of one’s mind.

The only way of trying to determine the factors fostering prevention is through longitudinal studies.  There are two longitudinal investigation—the Religious Orders Study and the Rush Memory and Aging Project, which have enrolled more than 3200 older adults across the United States.  This studies are being led by David A. Bennet at the Rush Alzheimer’s  Disease Center in Chicago.  The volunteers enter these studies dementia-free, anywhere from their mid-50s to their 100’s and agree to hours of testing each year.  They all have agreed to undergo autopsies once they have died.  Here are the two primary findings that have emerged from these investigations.

Virtually all brains in old age contain some pathological signs of Alzheimer’s disease, but only some people suffer any symptoms as a result.  Those who do not develop dementia appear to have greater cognitive reserve to fall back on.

Choices we make throughout life, from learning a second language or studying music in childhood to finding purpose and remaining physical, intellectually, an socially active in retirement can build cognitive reserve and dramatically reduce the risk of dementia.

It is hoped that growth mindsets capture the general nature of intellectual activity.  Mindfulness and meditation foster greater control over one’s cognitive activity and lead to better control over one’s emotions and enhance personal interactions.  The healthy memory blog certainly endorses physical activity and a healthy lifestyle which includes, obviously, a healthy diet.

Regarding the defining characteristics of Alzheimer’s, the neurofibrillary tangles and amyloid plaque, seem to have little or no effect on individuals who have built up this cognitive reserve.  And there has been little success in the development of drugs to treat these physical symptoms.  One of the foremost experts in this area, Peter J. Whitehouse, M.D., Ph.D, who is the senior author of “The Myth of Alzheimer’s”  does not think that successful medications will ever be developed.

Perhaps one of the best resources on the extensive research that has been done in the area can be found in the book, “Nurturing the Older Brain and Mind” by Pamela M. Greenwood and Raja Parasuraman.

Dr. Michael Merzenich has been called “the father of brain plasticity,” and the co-founder of Scientific Learning and Posit Science.  You can go to brainhq.com
and find brain training exercises.  These exercises can be helpful, but by themselves cannot be regarded as providing a cognitive reserve.  Building a cognitive reserve requires a lifestyle devoted to cognitive and physical health.  Dr. Merzenich also has an interesting book, “Soft-Wired:  How the New Science of Brain Plasticity Can Change Your Life.”

Research reviewed by Norman Doidge, M.D.  has documented the extreme plasticity of the brain.  It is truly plastic in its ability to recover from severe injury.   His research is documented in two books,”The Brain that Changes Itself” and The Brain’s Way of Healing:  Remarkable Discoveries and Recoveries from the Frontiers of Neuroplasticity.”

HM would like to see extensive research done on individuals suffering from Alzheimer’s who apparently failed to build up this cognitive reserve.  What level of recovery might be achieved through exercises designed to recover lost capacity?  And at what level of dementia might individuals still be recoverable?  HM believes that money spent on this research would be more valuable that the extensive work that is being done on drug treatments that are likely to be doomed to failure.  Unfortunately, the money is in potential drug sales.

There have been many previous HM posts on these topics.  Enter “Bennet,”  “Whitehouse,”  “Parasuraman,”  “Merzenich,”  “Doidge,”  “The Relaxation Response Update,’ and  “Mindfulness” to find them.

© Douglas Griffith and healthymemory.wordpress.com, 2016. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and healthymemory.wordpress.com with appropriate and specific direction to the original content.

Nature vs. Nurture: Genetics, Environment, and Cognition

June 17, 2014

This is the title of Chapter 12 in Greenwood and Parasuman’s Nurturing the Older Brain and Mind. They begin the chapter with a quote from Rene Dubos, So Human an Animal. “Genetics and experiential factors shape the biological and behavioral manifestations of human life, but they do not suffice to account for the totatality of human nature. Man also enjoys a great degree of freedom in making decisions; he is par excellence the creature that can choose, eliminate, organize, and thereby create.”

It is unfortunate but all too often the nature vs nurture issue is regarded as a deterministic dichotomy. Behavioral geneticists have done studies, identical twins have been frequently used, to estimate topics such as how much is IQ determined by genetics and how much is determined by the environment. What these studies neglect is the interaction between genetics and the environment. Neither exists in isolation from the other. Behavior and performance are the result of the interaction between genes and the environment.

Fortunately molecular genetics provides an alternative approach to behavioral genetics. The molecular approach allows for the study of specific genes and their alleles. This research has found that a particular allele of the apolipoprotein E (APOE) gene is a major risk factor for the development of Alzheimer’s. Pay attention to the term “risk factor.” Rather than causing Alzheimer’s this particular allele increases the risk of suffering from the disease. Moreover, it is possible that age-related cognitive decline may occur only in those who possess one or two copies of this allele. It is estimated that this could include about 14% of the US population.

The weight of evidence from research on this allele suggests that this risk factor interacts with lifestyle factors. Carriers of this allele obtain a greater benefit from exercise than non-carriers for late-life cognitive functioning. This benefit is most strongly evidenced when the exercise is carried out in mid-life. Cognitive experience also confers stronger benefits on allele carriers than people who do not carrier the allele. Understand that cognitive experience benefits everyone, but it is even more beneficial for those carrying this threatening allele.

So no evidence has been found that condemns any of us to Alzheimer’s or dementia. The activities covered in Nurturing the Older Brain and Mind and the healthymemory blog should be undertaken by all of us. This advice is further underscored for those with risk factors.

© Douglas Griffith and healthymemory.wordpress.com, 2014. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and healthymemory.wordpress.com with appropriate and specific direction to the original content.

Modifying the Work Environment and the Home Environment

June 15, 2014


Modifying the Work Environment and the Home Environment
is another chapter in Nurturing the Older Brain and Mind by Greenwood and Parasuraman.  It covers research in the field of Human Factors and Ergonomics.  I am a longstanding member in the Human Factors and Ergonomics Society.  The field of Human Factors and Ergonomics is devoted to designing technologies and environments so that they can be used effectively and safely.  Greenwood and Parasuraman note that their coverage of the broad area of human factors and ergonomic design for older adults is limited to just a few topics, including health-care technologies aimed at older adults and assistive technologies for the home.  They do provide references for more general coverage of basic research issues in human factors and aging.  There is much research into sensory-perceptual factors and interface designs and devices to compensate for losses in both sensory and motor functions that are not provided in the book.

Assistive technologies for self-care and “aging in place” are being developed.  This is especially important because more that 90 % of older adults live in their own homes, with relatives, or in independent-living facilities.  Older adults living alone are of special concern.  Some older people  have banded together so that they can age-in-place.  They organize self-help “villages” to screen service providers (repair technicians, for example) and other direct services such as meal delivery to dues-paying members.

The proper design of these assistive technologies has special importance for the elderly.  Daily we interact with and are frustrated by poorly designed devices (and software).  This frustration is exacerbated in the elderly who may abandon the use of the technology or, worse yet, use it improperly.

The Georgia Institute of Technology has been at the forefront of research to introduce “intelligent” technologies to help older adults age in place.  They have developed what they term the “Aware Home”, which is a conventional appearing house with many sensing and computing infrastructure designed to keep older individuals safe and improving their lives.  Information can be sent to a friend or relative to keep them aware of where the individual is in the house and what they are doing.

Honeywell has developed an Independent Living Lifestyle Assistant (ILSA)to support an independently living  older person with extensive monitoring and management (including the monitoring of temperature, blood pressure, and heart rate)  and with the ability to control remotely lights, power, a thermostat, door locks, and water flow.  There are many sensitive issues implementing these systems indicating that more research needed to be done.  Overreliance and complacency are two of the problems that need to be addressed.  Continued research will yield improved systems, and technology can be employed in an a ad hoc manner.  Imagine using Skype to keep tabs regularly on an older friend or relative.   Enter “Aging in Place Technology Watch”  to learn of a large range of activities taking place in this area.  aginginplace.com offers a wide range of information and products

© Douglas Griffith and healthymemory.wordpress.com, 2014. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and healthymemory.wordpress.com with appropriate and specific direction to the original content.

Cognition Enhancing Drugs

June 10, 2014

Cognition Enhancing Drugs is the title of a chapter in Nurturing the oder Brain and Mind By Greenwood and Parasuaman.  They note that “there is little doubt that estrogen protects both the brain and cognitive functioning not only in younger female animals and in women undergoing surgical menopause, but also in middle-aged women around the time of natural menopause.  Unfortunately subsequent research revealed  the health risks of initiating estrogen and progesterone use in women many years after menopause.  However, the situation is confusing as  additional research has been conflicting and the situation remains unresolved.    Greenwood and Parasuraman conclude, “We should await results from newer better-designed studies before drawing conclusions about the benefits and costs of estrogen in women.”

Greenwood and Parasuraman note that the effects of other cognitive-enhancing drugs on older people have been little studied.  Perhaps this is because research has been targeted at  developing drugs that either cure of prevent Alzheimer’s.   Drugs that have been developed only slow the progression of the disease.  To my way of thinking this is only prolonging the agony.  Moreover, there is reason to believe that a drug that cures or prevents Alzheimer’s might never be developed (See the healthy memory blog post, “The Myth of Alzheimer’s”).

Greenwood and Parasuraman find it strange that the benefits of  cholinergic agonists for benefits in young people, that cholinesterase inhibitors have been so little studied in older people.  Again, in my view, this is due to the preoccupation with finding a cure or a preventive vaccine.  Perhaps as a result of their review some attention will be turned to this approach.
Caffeine is beneficial, but with this exception there is no current compelling evidence that pharmacological agents are useful for ameliorating cognitive aging.

© Douglas Griffith and healthymemory.wordpress.com, 2014. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and healthymemory.wordpress.com with appropriate and specific direction to the original content.

 

The Benefits of Physical Exercise

June 5, 2014

 

This post is taken from Nurturing the Older Brain and Mind by Greenwald and Parasurman.  They write in the summary of their chapter on physical exercise, “Of the various experiential and lifestyle factors in cognitive aging, which they have reviewed in their book, physical exercise is probably the one whose effects are best understood.  They reviewed literature on non-human in addition to human subjects.  They write, “There is strong evidence that aerobic exercise can reduce and in some cases eliminate cognitive deficits associated with healthy aging.”    Exercise benefits neurogenesis and synaptic plasticity.  Neurotrophins also are produced as a result of exercise and mediate  the beneficial effects of exercise. They also note that there is a growing understanding of the neural mechanisms that underlie such benefits.  They note that the mechanisms appear to be centered on the dentate gyrus.   The dentate gyrus is important for the formation of new memories.

Although knowing the neural mechanisms of the benefits of exercise is good, many readers would like to know how much exercise is “enough.”  Unfortunately, there is little information on this topic.  All I can cite is a previous healthy memory blog post, “To Improve Your Memory, Build Your Hippocampus.”  In that study people benefited from walking briskly for 45 minutes three days a week for six months.  So there is evidence that that amount is sufficient.  So if you enjoy exercising, please do more, if you do not, try to do something of the order of 45 minutes a day for three days a week.  I have a hunch that any physical exercise one does is beneficial, but data regarding the minimum amount that is beneficial is woefully lacking.  It is good to do something you enjoy.  The feeling both doing and after a workout can be quite enjoyable.  Frankly, I find exercising easier than dieting and nutrition, to which we shall turn next.

© Douglas Griffith and healthymemory.wordpress.com, 2014. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and healthymemory.wordpress.com with appropriate and specific direction to the original content.

A Neurocognitive Framework for Ameliorating Cognitive Aging

May 31, 2014

This post is taken from a chapter with the same name, “Ameliorating Cognitive Aging:  A Neurocognitive Framework”  in the book Nurturing the Older Brain and Mind  by Greenwood and Parasuraman.  Brain aging needs to be dealt with.  There is cortical shrinkage and there are white matter changes.  The shrinkage and white matter changes have a small effect on cognitive performance.  Neurotransmitter  dysfunction is a matter of more concern.  Then there are genetic factors.  First of all there is the genotype, then the gene expression from this genotype.  Although some individuals suffer from a genetic predisposition to dementia, these are not deterministic, but rather predispositions.  That is, given such and such experiences or external factors, the likelihood of dementia increases.  Then there are epigenetics, which determine how the genes are actuated.  Epigenetics are affected  by lifestyle and experiential factors such that favorable factors can enhance the probability of favorable genetic readouts.

Turning to the lifestyle and experiential factors, education, exercise, diet, learning and training, and combinations of these factors enhance the likelihood of good cognitive performance throughout one’s lifespan.   More details on these individual factors will be provided in subsequent healthymemory blog posts.

Then there is the matter of neuronal plasticity that includes neurogenesis, synaptogenesis, dendritic arborization, and network reorganization.   An example of network reorganization is the greater use of both hemispheres as we age.  When I was a graduate student I was taught that our nervous system was fixed and could not be modified when damaged or was damaged to aging.  Fortunately, what I was taught as a graduate student has been found to be woefully in error.  These processes can occur well into old age.  But they need to be activated by new learning and experiences for them to occur.

Next there is cognitive plasticity.  Top-down processing strategies can be used to make better use of our accumulated knowledge.  Then there are our well-developed prefrontal lobes for effective executive functioning.

I have often written of the importance of building a cognitive reserve.  Although advice was provided as to how to build one’s cognitive reserve, Greenwood and Parasuraman have provided the first neurocognitive framework to explain how this occurs.

© Douglas Griffith and healthymemory.wordpress.com, 2014. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and healthymemory.wordpress.com with appropriate and specific direction to the original content.