Posts Tagged ‘Greenwood’

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.

Combined Effects of Interventions and Preventative Actions

June 12, 2014

Combined Effects of Interventions and Preventative Actions is another chapter in Nurturing the Older Brain and Mind by Greenwood and Parasuraman.  Unfortunately, this is a very short chapter, and the reason that this is a short chapter is that very little research has been done on this topic.  This is unfortunate as the few studies that have been done suggest that there are real benefits from combined interventions.  “The general conclusion is that lifestyle factors have greater beneficial effects on cognitive aging when they are jointly experienced than when individually experienced.”   Research has found additive effects of diet, exercise, and cognitive training.  Given this, the obvious question is why additional research into these areas has not been done.  Perhaps the obvious answer is that such research is expensive.

Here I need to put on my editorial cap.    It seems to me that it would be in the interest of the retirement home community to conduct their own research on this topic.  They are the ones best situated to conduct such research.  They already provide a community setting, and there are laws requiring certain activities be offered.  I have seen the progression my mother made from independent living to assisted living, and I have vowed not to follow this same route.  There are ads out the wazoo from many retirement communities about the paradise and freedoms their communities  offer.  I have  seen only one advertisement  for a program  nurturing the aging brain and mind.  That advertisement was for Home Care Asistance, http://www.HomeCareAssistance.com,  that offers a program for keeping the mind sharp base on a Cognitive Therapeutics Method, http://www.cognitivetherapeutics.com.  Although I have no data on the effectiveness of this program, it at least offers a program.   I want to see more advertisements offering programs to keep me cognitively engaged so that I can continue to pursue a growth mindset.  Moreover, I would like to see promises of on-going research, so that I might not only benefit but would also be contributing to new approaches.

It would be in the interest of at least the higher end communities to conduct such research, to offer such programs, and to make such commitments.  Absent any compelling commitments regarding ongoing programs and future research, I would never consider setting foot in any of these communities.

© 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 Diet and Nutrition on Nurturing the Older Brain and Mind

June 8, 2014

This post draws heavily on the chapter on the benefits of diet and nutrition in Nurturing the Older Brain and Mind by Greenwood  and Parasuraman.  They do not conclude that there are no benefits of diet and nutrition on cognition.  Rather they are concluding that most evidence for this claim is weak.

Now there is strong evidence that dietary restriction with respect to calories consumed does confer significant benefits for cardiovascular health, but there is no strong evidence for its benefits on cognition.  We often read that what is good for the heart is good for the brain and cognition, but that is not necessarily so.  Consumption of foods containing reservaterol may confer benefits on healthy and cognition that are similar to dietary restriction.  Greenwood and Parasuraman are hesitant to make this recommendation due to the dangers of alcohol abuse.  Here your healthy memory blog post author will say that along as alcohol is not abused, there are benefits.  Indeed, moderate alcohol consumption, one or two drinks per day, has been found to have benefits on health in general.

Goodman and Parasuraman also note that the substitution of polyunsaturated fatty acids for saturated fat in the diet has convincing evidence for the human risk of heart disease, but the evidence for beneficial effects on human cognition is inconclusive.

Goodman and Parasumanan state that there is little evidence that B-vitamin supplementation has any beneficial efftext on the brain or cognition.

Well-controlled studies of the effects of specific foods, spices, herbs, and micronutients are few in number and the results are inconclusive, but there is some evidence for the benefits of antioxidants in the diet consistent with other evidence for a ole of oxidative stress in negative effects on aging.

The Benefits of Diet and Nutrition on Nurturing the Older Brain and Mind

This post draws heavily on the chapter on the benefits of diet and nutrition in Nurturing the Older Brain and Mind by Greenwood  and Parasuraman.  They do not conclude that there are no benefits of diet and nutrition on cognition.  Rather they are concluding that most evidence for this claim is weak.

Now there is strong evidence that dietary restriction with respect to calories consumed does confer significant benefits for cardiovascular health, but there is no strong evidence for its benefits on cognition.  We often read that what is good for the heart is good for the brain and cognition, but that is not necessarily so.  Consumption of foods containing reservaterol may confer benefits on healthy and cognition that are similar to dietary restriction.  Greenwood and Parasuraman are hesitant to make this recommendation due to the dangers of alcohol abuse.  Here your healthy memory blog post author will say that along as alcohol is not abused, there are benefits.  Indeed, moderate alcohol consumption, one or two drinks per day, has been found to have benefits on health in general.

Goodman and Parasuraman also note that the substitution of polyunsaturated fatty acids for saturated fat in the diet has convincing evidence for the human risk of heart disease, but the evidence for beneficial effects on human cognition is inconclusive.

Goodman and Parasumanan state that there is little evidence that B-vitamin supplementation has any beneficial efftext on the brain or cognition.

Well-controlled studies of the effects of specific foods, spices, herbs, and micronutients are few in number and the results are inconclusive, but there is some evidence for the benefits of antioxidants in the diet consistent with other evidence for a ole of oxidative stress in negative effects on aging.

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.

An Important Book for All to Read

May 26, 2014

And that book is Nurturing the Older Brain and Mind by Pamela M. Greenwood and Raja Parasuraman of George Mason University.  The book is an extensive review of the literature on the older brain and mind in general, and on Alzheimer’s and dementia, in particular.  Although younger people might think this book is only for us BabyBoomers that would be WRONG WRONG WRONG!  First of all, the magnitude of the problem must be considered.  As people age the probability of suffering  Alzheimer’s increases and with aging populations it will soon reach epidemic proportions.  Hopes for drug cures or preventative vaccines are slim (see the healthy memory blog posts, “The Myth of Alzheimer’s” and “Sigmund Freud and Alzheimer’s Disease”).   Moreover actions you take now can reduce the likelihood of suffering from Alzheimer’s or dementia.  If you have parents, there are things they can do to reduce the likelihood of suffering from Alzheimer’s or dementia.  And if you have children, there are things that both you and your children can do to reduce the likelihood of Alzheimer’s and dementia.  These “activities” or “things” are described in Nurturing the Older Brain and Mind.

Greenwood and Parasuraman note that although the brain might age, cognitive aging is neither universal nor inevitable.  Most individuals do not show a decline in cognitive functioning in old age, even though the probability of suffering such a cognitive decline increases as we age.  Moreover it has been noted in many healthymemory blog posts that there are many individuals who do not suffer cognitive decline in spite of the tell-tale amyloid plaque and neurofibril tangles of Alzheimer’s.  The only explanation of this fact has been that these people have developed a cognitive reserve.  Greenwood and Parasuraman present a neurocognitive framework to describe how this might be done.

Nurtuiing the Older Brain and Mind is a  scholarly work of the highest order reviewing an extensive research literature on the topic including both human and non-human species.  Nevertheless, I believe that it is written on a level where it should be accessible to the general reader.  Even if it takes a bit of a reach for the general reader, it is a reach well worth taking.  Although the healthymemory blog will draw heavily on this work, there is no way I can even hope of doing it justice.

© 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 only criticism I have of this work is that it does not address mindfulness, although I do understand why it was not addressed.  Part of the reason can be found in the immediately preceding blog post on random controlled trials or random clinical trials (RCTs).  The researchers do not regard the research on mindfulness as being significantly “rigorous.”  I remember when I was a graduate student there was a debate on whether we humans can control our autonomic nervous systems with out minds (heart rate, for example).  Now there were people in the east who were highly trained meditators who were able to do this.  Nevertheless, most psychologists would not accept this conclusion unless they could train someone to do it in a psychological laboratory.  They regarded these meditators as using some sort of “trick.”  Well the same thing has been said of mnemonic techniques, but these mnemonic techniques not only enhance memory, but also reveal important insights into how memory works.  Similarly mindfulness research will provide practical insights into how we can control our minds and our bodies.  These skills will be central not only to preserving cognitive functioning, but also to enhancing cognitive functioning.   I predict that mindfulness will play an increasingly strong role in nurturing the older brain and mind.