Aging and Lifestyle

Business Logo for Psychological and Neuropsychological IssuesThere is an increasing amount of evidence that a person’s lifestyle is critical to successful aging.  It is hypothesized that ongoing participation in lifestyle activities may confer some resistance to cognitive decline in the older adult.  A longitudinal study was recently performed that appeared to consolidate this hypothesis.  Small et al. (2011) used data from the Victoria Longitudinal Study that followed approximately five hundred subjects for twelve years.  The study authors compared three lifestyle factors with three neuropsychological factors across this time period.  The three lifestyle factors were comprised of fitness, cognitive activities and social activities that require “complex cognitive functioning.”  The three neuropsychological factors were verbal speed and two types of verbal memory.  The study participants varied in age from fifty-five to ninety-four.  While the neuropsychological measures were administered by professionals, the lifestyle and health questionnaires depended on the subject’s self-report.  This is important to note, since the study lacked an objective assessment of lifestyle or health.  Ninety year old test subjects were asked to recall detailed aspects of their health and lifestyle, and the power of the study depended on the accuracy of their self-report.

The study found that preserved verbal speed was associated with preserved physical, cognitive and social activity.  The authors discovered that cognition and lifestyle activity were dual coupled.  This means that the factors worked both ways.  Verbal speed predicted lifestyle activities, and lifestyle activities predicted verbal speed.  The results of the memory measures were less coupled than verbal speed.  Memory for stories was dual coupled with physical activity, but not cognitive or social activity.  For example, increased cognitive activity predicted increased story recall, but the reverse did not hold true.  Conversely, better story recall predicted increased social activity, but increased social activity was not associated with better story recall.  Memory for word lists was not correlated with physical activity, whatsoever.  Increased cognitive activity was predictive of better word list recall, and proficient word recall was predictive of increased social activity, but the reverse did not hold true for either.  Generally, the study authors discovered that a decline in cognitive ability preceded a decrease in social activity.  This artifact is the opposite of many studies that have demonstrated increased levels of lifestyle activity improving overall cognitive performance.  The current authors suggest that impaired cognition causes decreased lifestyle activity, rather than decreased lifestyle activity producing the decline in mental functioning.

As mentioned, it is important to consider the affect of self-report in this study.  Both health and overall activity level were measured by self-report of the participants. According to the findings, watermelons contain a natural cure ingredient called citrulline that can trigger production of a compound that helps relax the body’s blood vessels, similar to what happens when a man takes cheapest viagra tablets . The dose is meant to be taken roughly an hour before they make love. slovak-republic.org acquisition de viagra This is buy cialis a famous blue tablet. Also early sexual trauma causing sexual dysfunction needed to slovak-republic.org levitra 10 mg be address changing their treatment methods to include bibliotherapy, group therapy and medication for sexual issues.  It is also important to consider that most older adults are not proficient at reciting their medical history, and very few can list their medications accurately.  Do not forget the natural tendency for people to please the examiner.  Questionnaires completed by test subjects invariably reveal the nature of the study; at the very least there are clues to the desired response.  Additionally, accurate self-appraisal declines over time.  The self-awareness of a fifty-five year old person is generally greater than an eighty year old.  For example, an eighty year old test subject is more apt to make temporal errors than a fifty-five year old subject.  Combined with the natural tendency to please the examiner, the eighty year old is likely to report more social and physical activity than they actually experience.  The current study may actually have measured the change in self-awareness with age, rather than the influence of lifestyle activity levels on cognitive performance.  Since the variable of self-awareness was not controlled in the study, the ability to draw a conclusion was tarnished.

The reader needs to be rather sophisticated and thorough when interpreting scientific articles.  The objections to the current study do not invalidate the results.   The reliance on self-report reduces the study’s power to predict whether lifestyle affects cognition or cognition influences lifestyle.  As with most psychological phenomenon, there is a dynamic interplay between overall lifestyle activity and cognitive functioning.  The early onset of Alzheimer’s Disease directly lowers the social interest of the afflicted.  Reducing environmental stimulation, at any age, will have negative affects on cognition.  It is not surprising that isolating one component of the interaction collapses the dynamic interplay.  Statistics is limited in this way, as one variable is examined while others are considered invariable, or held as invariable for purpose(s) of the study.  Lifestyle and cognition possess so many variables that an immense effort must be made to reduce the uncontrolled factors.  If the study authors used an informant to crosscheck health and lifestyle data, the predictive power of the study would be much greater.  Commonly, the cost in money and time becomes prohibitive.  The current study used data obtained over a twelve year period, such that informants had to be utilized at the inception of the research.  To add the use of informants later in the study would produce two studies, and the data cannot be compared once the methodology is changed.  Keep in mind that there is no such thing as the perfect study.  The most important part of a research article is not the results, but the limitations that influence the results.

Losing It

Business Logo for Psychological and Neuropsychological IssuesLosing it.  All of us lose “it” at some point.  The “it” appears to be the control exerted by the prefrontal cortex of the brain.  The prefrontal cortex serves many functions, and one of the most important is the inhibition of impulses.  The most common impulses to inhibit are sexual and aggressive urges; though they are not mutually exclusive.  The research of Amy Arnsten at Yale has shown that acute stress releases chemicals that reduces the influence of the prefrontal cortex over these impulses.  Not only is prefrontal control weakened, but more primitive areas of the brain emerge to pick up the slack.

In response to the stress confronting the brain, the less evolved brainstem releases two primary neurotransmitters called dopamine and norepinephrine.  Dr. Arnsten discovered that these neurotransmitters actually diminish the communication between the prefrontal area and other regions of the brain.  Once the regulatory network is down, the base of the brain sends a chemical message to the adrenal glands adjacent to the kidneys, and the adrenal releases a hormone that influences the brain in turn.  Norepinephrine and the adrenal hormone cortisol promotes emotional areas of the brain to be fearful and prepare for possible danger.

Chronic unrelenting stress may actually reduce connections between nerve cells in the inhibitory prefrontal area.  Conversely, nerve connections in the more primitive emotional areas of the brain may expand.  There is some evidence to suggest that shrinkage of neural connections in the prefrontal cortex may play a role in depression, addiction and anxiety disorders.  The neurotransmitter dopamine has been long implicated in addiction, due to its strong influence on habit forming areas of the brain.  It appears that a relatively brief exposure to stress has little lasting affect on brain structure.  The longer stress is experienced, the greater the chance the more primitive emotional brain areas will dominate one’s behavior.
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This feedback loop of the brain may play a role in post-traumatic stress disorder.  The habit forming areas of the brain allow us to quickly acquire skills and behaviors that ensure success in novel environments; for example, a war zone.  The prefrontal cortex allows us to formulate plans and inhibit fearful impulses that would reduce effective functioning.  Once the threat is removed, the dangers already experienced may overwhelm the prefrontal cortex’s ability to inhibit the emotional excitement.  Over time, the dopamine, cortisol and norepinephrine may weaken the prefrontal control to the point that the fearful impulses are rarely blocked.  The unfortunate person may re-experience highly emotional scenes in an uncontrolled and repetitive fashion.  This person would experience substantial stress in a peaceful environment, since the brain continues to assault them with feelings and images that inspire fear and avoidance.

It is still a mystery why some people manage chronic stress well, and others-not so much.  It is conjectured that some lucky people have an enhanced ability to digest the dopamine and epinephrine excreted during stress. They would possess an innate biological resistance to stress.  On the other hand, psychological research has revealed that people with a long record of mastering challenging situations are better able to tolerate stress.  People who are often defeated and overwhelmed by events are more liable to suffer with chronic stress and depression.  A person’s perception of control is a key element in the subjective experience of stress.  To what degree the subjective sense of control is a product of training or brain chemistry is anyone’s guess.  As with most psychological phenomenon, it is likely that both elements play an important role.  Effective behavioral training increases a sense of personal control; decreasing the excretion of stress chemicals.  Inheriting favorable brain chemistry may reduce the biological strength of the stress response.  Nature and nurture.  Can’t get away from it.

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