Archive for February, 2015

Ischemic Stroke and Cognitive Function

February 25, 2015

This blog post is largely based on an article by Marina Fernandez-Andujar and eleven others titled, “Remote Thalamic MIcrostructural  Abnormalities Related to Cognitive Function in Ischemic-Stroke Patients,” published in Neuropsychology (2014), 984-996. Ischemic Stroke or Transient Ischemic Attack (TIA) is a brief period of lack of blood flow to an area of the brain.  This impairs the function of brain cells, so a person suffering from TIA develops symptoms of brain function impairment, such as
Weakness of the face and/or arm, and/or leg muscles on one side of the body
Numbness of face and/or arm and/or leg on one side of the body
Inability to understand spoken language
Inability to speak
Unexplained dizziness or vertigo
Loss of vision through one eye
Double vision or blurry vision
These symptoms of a mini stroke/TIA disappear completely within 24 hours.  Nevertheless, it is important to visit an emergency room as soon as possible.  Even if the event occurred a few days ago, medical attention should still be sought.

The thalamus is a midline symmetrical structure of two halves, within the vertebrate brain, situated between the cerebral cortex and the midbrain. Some of its functions are the relaying of sensory and motor signals to the cerebral cortex, and the regulation of consciousness, sleep, and alertness. The two parts of the thalamus surround the third ventricle. It is the main product of the embryonic diencephalon.
The study compared 17 patients who had suffered right hemisphere ischemic stroke three months previously with 17 controls matched for age, sex, and years of education.

In the interest of brevity, technical terms will not be defined and certain details will be omitted. However, this article reports the results of sophisticated brain imaging and contains a wealth of information for the technical specialist.  Stroke patients showed lower fractional anisotropy (FA) values and higher mean diffusivity (MD) values in specific areas of the right thalamus compared with  controls.  In patients, decreased FA values were associated with lower verbal fluency performance in the right thalamus, and the left thalamus after adjusting for diabetes mellitus.  Increased MD values were associated with lower verbal fluency performance in the right hemisphere after adjusting for diabetes mellitus. The FA and MD values were not related to any cognitive function in the control participants.

Alzheimer’s research has been largely focused on neurofibrillary tangles and amyloid plaques in spite of autopsies indicating the presence of these abnormalities, but not cognitive or behavioral of Alzheimer’s symptoms during the lifetimes of these individuals.  It is important to be aware that dementia can also result from ischemic strokes or Type II diabetes mellitus.

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The Benefits of Physical Exercise & Cognitive Training on the Executive Function of Older Adults

February 22, 2015

As the name implies, executive function is important.  It involves the prefrontal cortex, which has a high level of neural plasticity (Miller, E.K., & Cohen, D.J. (2001),  “An Integrative Theory of Prefrontal Cortex Function,” Annual Review of Neuroscience, 24, 167-201. doi:10.1146/annurev.neuro.24.1.167), meaning that it is amenable to training.  This current blog post provides a very brief summary of an article by Justin E. Karr, Corson N. Areshenkoff, Phillipe Rast, and Mauricio A. Garcia-Barrera titled “An Empirical Comparison of the Therapeutic Benefits of Physical Exercise and Cognitive Training on the Executive Functions of Older Adults:  A Meta-Analysis of Controlled Trials” in Neuropsychology (2014), 829.845.

A meta-analysis is an analysis of a large body of research.  This one involved 46 studies, 23 involving physical exercise (PE), 21 cognitive training (CT), and 2 involving both.  Cognitive training did not work for individuals who were already cognitively impaired.  Otherwise, both types of training improved executive functions, but CT presented potential advantages for specific types of cognitive functions.  The immediately previous post discussed these executive functions:  working memory, inhibition, executive attention, problem solving, and fluency.  The review found that cognitive training on problem solving had the largest beneficial effect on the measure of Independent Activities of Daily Living (IADL).

Although the study found that the effects of cognitive training were larger than physical exercise, they qualified this conclusion.  I would contend that it is foolish to argue which is better.  They both provide benefit.  Presumably the major benefit from physical exercise is due to aerobic activity increasing oxygen flow to the brain.  I am curious as to whether any activity that increases respiration might be beneficial,  laughing for example.  Feel free to add whatever techniques you can think of for increasing respiration.  I think it would be worthwhile for researchers to explore possible benefits of these types of activities.  One of the primary advantages of cognitive training is that they can be targeted at specific cognitive functions.  Further research could be explored at designing training to improve specific functions where training is most needed.  The types of training might vary among individuals.  This meta-view has found that, general speaking, problem solving skills had the largest effect.

© Douglas Griffith and healthymemory.wordpress.com, 2015. 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.

Five Constructs for Executive-Related Cognitive Abilities

February 18, 2015

This post addresses five constructs, or factors, dealing with executive related cognitive abilities.  They are obviously important because these are cognitive abilities at the executive level.  They also have special relevance for aging memory.  These factors play an important role in the assessment of Independent Activities of Daily Living (IADL).  IADL plays an important role in determining whether individuals are capable of living independently.  These factors are working memory, inhibition, executive at the attention, problem solving, and fluency.  Each factor will be briefly explained and discussed with respect to the healthy memory blog, “The Myth of Cognitive Decline.”

The most common example given of working memory is trying to remember a phone number you have just be given or read until it is dialed.  This is the magic number of 7 plus or minus two that has been revised down to five plus or minus two.  Actually, the size of the individual items affects the number that can be remembered.  Information must be rehearsed or actively used  or the information will be lost.  As the “Myth of Cognitive Decline” is addressing the phenomena of long term memory, working memory is not part of the myth.  Working memory does tend to decline as we age, although research has been done to demonstrate that it can be enhanced.

Inhibition refers to irrelevant information coming to mind when you are trying to remember or solve a problem.  This does increase as we age.  And it is the large amount of information held in long term memory that the “Myth of Cognitive Decline” addresses, that is likely increasing inhibition.  Simply put, there is more information to serve as the source of inhibition.  Given enough time, this inhibition can be overcome.

Executive attention refers to the managing and selection of information in trying to perform some task or to solve some problem.  The problem here for us as we age is that there is more information to attend to.  Again, given enough time, decreases in this ability can be overcome.

Problem solving refers to the marshaling of attention to solve  a problem.  Examples of problems addressed with IADL are planning a meal, planning a trip, managing finances, and so forth.  Although the more experienced mind has more information to solve problems, when there are time constraints, the additional information can be a problem as captured in the statement, “too much knowledge for one’s own good.”

Fluency is the ability to generate ideas or certain types of words (words beginning with “q”, vegetables, and so forth).  Here the older brain is at an advantage, but again, the pressures of time constraints can create problems.  A caveat to the “Myth f Cognitive Decline” is “given enough time.”

Recall, particularly of information from longer term memory, often involves problem solving.  When trying to remember the forgotten name of a particular actor for example, one might try to remember the movies the actor was in, the dates of the movies, and other actors.  Sometimes remembering a particular sound can help in the generation of candidate names.  What is interesting about these attempts is that the memory will suddenly pop into mind hours or days later.  Apparently memory search has been continuing in our non-conscious minds.  This is one of the reasons I think that these periodic memory searches contribute to memory health.  When we do these searches we are activating long unused memory circuits and reactivating them.  I have no carefully controlled research to back up my conjecture, but I think it is a compelling conjecture.  Perhaps some graduate student will undertake this research for a Master’s Degree or Ph.D.

© Douglas Griffith and healthymemory.wordpress.com, 2015. 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.

Still Alice?

February 14, 2015

Still Alice is the popular film about an esteemed university professor who is struck with early onset Alzheimer’s.  She has everything: talented daughters, a loving husband who is also on the faculty of Columbia University, along with her brilliant career.  We watch as her memory gradually slips away.  She is no longer capable of serving as a university professor.  She sets up a series of tests for herself on her personal computer.  She leaves instructions to herself on the computer as to how to commit suicide should she fail these tests.  Her disease progresses until she is no longer able to find the bathroom in her home.   She does not commit suicide.  Instead she joins an Alzheimer’s Support Group and gives a presentation that in spite of her difficulties, she will continue to soldier on, that she is still Alice.  At the end of the film, her daughters are taking turns caring for her, as her husband has moved to a new job.  It is here that the movie ends.

But what if the movie had continued to follow the likely course of her disease?  It is likely that it is only a matter of time until she will no longer recognize her daughters, or that she will remember that she even had daughters.  Eventually, she might get to the point where she does not know who she is and holds no memories of the life of Alice.  Then the question becomes, is she still Alice?

One might ask that if someone who does everything right with respect to a healthy mind and brain can end up succumbing to Alzheimer’s, what’s the point in following advice from the healthy memory blog?  There is also the suggestion that Alice had a genetic predisposition to the disease.  It is important to understand, that although a genetic predisposition can increase the likelihood of succumbing to Alzheimer’s, the relationship is not deterministic.  That is, people can be found with the gene who do not succumb to Alzheimer’s.  So we return to the question as to why something like this could happen to someone as golden as Alice?  We must always remember that nothing in life is guaranteed.  We can do what we can to achieve success and to avoid problems, but there is always an element of chance that it involved.  So the best we can do is work to achieved favorable odds, while remembering that there are no guarantees.

© Douglas Griffith and healthymemory.wordpress.com, 2015. 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.

There Will Be Another Brief Hiatus in New Posts

February 1, 2015

Nevertheless with more than 550 Healthymemory Blog posts I think there is sufficient reading material.  If I had to recommend one blog post to read it would be “The Myth of Cognitive Decline.”  This can be found by entering this title in the search box of the healthy memory blog.  This search block can be used to identify blog posts on the following topics.

Posts based on whom I regard as the most important cognitive psychologists:  Nobel Prize Winner Kahneman, plus Stanovich and Davidson.  There are posts on the important topics of attention and cognitive reserve.  Other topics of potential interest are The Flynn Effect, mindfulness, meditation, memory champs, contemplative computing, behavioral economics, dementia, and Alzheimer’s.

Of course, you are encouraged to enter any of your favorite topics into the healthymemory blog search block

Enjoy.  I shall return.

© 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.