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Wednesday, September 1, 2010

My bvFTD Symptoms - Stress and Memory

Stress and Memory (still even yet... again) - Did I have one Margarita... or was it six!?

(Everything here is my account of what happened to me, or my interpretation of stuff. Every case of FTD is different. Keep in mind as you read this that the person who wrote this has dementia.)
       
I have noticed that when I am stressed my memory is much worse. My guess is that it not only is affecting my memory as noted below, but also my attention. When any one part of the Executive Functions breaks down it affects all of the others. My emotions just go along for the ride. I have also noticed that I subconsciously avoid and reduce stress. This is natural, but I may be doing it a little more than before. Stress never really bothered me in the past. That is a change I attribute to bvFTD.

It isn't like I thought of this all on my own. My Neurologist has mentioned it to me on several occasions when we discuss my attention and memory issues. In his opinion they will be more pronounced if I am under stress.

Well! I have been under constant stress for months. Duh! I have had some time periods of greater stress due to financial, and emotional issues. These times of high stress have caused my symptoms to be noticeably worse.

I just gotta chill. Zen! Be the pool! Ommmmmm! Become one with the water. Crap! That stuff never worked for me. Pour me a Margarita, and hand me a skunk! Ahhhhh! That's better!


The information below is copied directly with permission and special thanks from The Franklin Institute website.

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Chronic over-secretion of stress hormones adversely affects brain function, especially memory. Too much cortisol can prevent the brain from laying down a new memory, or from accessing already existing memories.

The renowned brain researcher, Robert M. Sapolsky, has shown that sustained stress can damage the hippocampus , the part of the limbic brain which is central to learning and memory. The culprits are "glucocorticoids," a class of steroid hormones secreted from the adrenal glands during stress. They are more commonly know as corticosteroids or cortisol .

During a perceived threat, the adrenal glands immediately release adrenalin. If the threat is severe or still persists after a couple of minutes, the adrenals then release cortisol. Once in the brain cortisol remains much longer than adrenalin, where it continues to affect brain cells.

Have you ever forgotten something during a stressful situation that you should have remembered? Cortisol also interferes with the function of neurotransmitters, the chemicals that brain cells use to communicate with each other.
         
Excessive cortisol can make it difficult to think or retrieve long-term memories. That's why people get befuddled and confused in a severe crisis. Their mind goes blank because "the lines are down." They can't remember where the fire exit is, for example.

Stress hormones divert blood glucose to exercising muscles, therefore the amount of glucose – hence energy – that reaches the brain's hippocampus is diminished. This creates an energy crisis in the hippocampus which compromises its ability to create new memories.
         
That may be why some people can't remember a very traumatic event, and why short-term memory is usually the first casualty of age-related memory loss resulting from a lifetime of stress.       

In an animal study, rats were stressed by an electrical shock, and then made to go through a maze that they were already familiar with. When the shock was given either four hours before or two minutes before navigating the maze, the rats had no problem. But, when they were stressed by a shock 30 minutes before, the rats were unable to remember their way through the maze.

This time-dependent effect on memory performance correlates with the levels of circulating cortisol, which are highest at 30 minutes. The same thing happened when non-stressed rats were injected with cortisol. In contrast, when cortisol production was chemically suppressed, then there were no stress-induced effects on memory retrieval.
         
According to James McGaugh, director of the Center for the Neurobiology of Learning and Memory at the University of California, Irvine, "This effect only lasts for a couple of hours, so that the impairing effect in this case is a temporary impairment of retrieval. The memory is not lost. It is just inaccessible or less accessible for a period of time."12       
Normally, in response to stress, the brain's hypothalamus secretes a hormone that causes the pituitary gland to secrete another hormone that causes the adrenals to secrete cortisol. When levels of cortisol rise to a certain level, several areas of the brain – especially the hippocampus – tell the hypothalamus to turn off the cortisol-producing mechanism. This is the proper feedback response.
         
The hippocampus, however, is the area most damaged by cortisol. In his book Brain Longevity, Dharma Singh Khalsa, M.D., describes how older people often have lost 20-25% of the cells in their hippocampus, so it cannot provide proper feedback to the hypothalamus, so cortisol continues to be secreted. This, in turn, causes more damage to the hippocampus, and even more cortisol production. Thus, a Catch-22 "degenerative cascade" begins, which can be very difficult to stop.

Studies done by Dr. Robert M. Sapolsky, Professor of Neurology and Neurological Sciences at Stanford University, showed that lots of stress or exposure to cortisol accelerates the degeneration of the aging hippocampus.
         
And, because the hippocampus is part of the feedback mechanism that signals when to stop cortisol production, a damaged hippocampus causes cortisol levels to get out of control – further compromising memory and cognitive function. The cycle of degeneration then continues. (Perhaps similar to the deterioration of the pancreas-insulin feedback system.)

The study was titled "Cortisol levels during human aging predict hippocampal atrophy and memory deficits". A third of the 60 volunteers, who were between ages 60 and 85, had chronically high cortisol levels, a problem that seems to be fairly common in older people.13
         
The size of the hippocampus averaged 14% smaller in one group and showed high and rising cortisol levels, compared to a group with moderate and decreasing levels. The small hippocampus group also did worse at remembering a path through a human maze and pictures they'd seen 24 hours earlier and – two tasks that use the hippocampus.
       
Using magnetic resonance imaging, Mayo Clinic researchers found that specific changes in the hippocampus were linked to changes in behavior associated with aging and Alzheimer's disease. "When certain parts of the hippocampus shrink or deteriorate, specific, related memory abilities are affected," says neurologist Ronald C. Petersen, the principal author of the study.

Furthermore, individuals with a shrunken hippocampus tend to progress more rapidly towards Alzheimer's.
         
"In earlier studies we were able to show that the volume of the hippocampus could help diagnose early Alzheimer's disease or help predict which patients may develop Alzheimer's disease in the future. Now we can look specifically at which part or parts of the hippocampus are affected and match that with particular memory functions which are impaired in that particular patient," says Dr. Petersen.14
       
In a 2000 human study, McGaugh and researchers at the University of Zurich asked 36 healthy adults to memorize 60 unrelated nouns that were displayed for four seconds each on a computer screen. Study participants were then tested to see if they could remember the words immediately after they learned the list, and then again, a day later.

Subjects took a tablet of cortisone (precursor of cortisol) or a placebo: either one hour before the initial word presentation; just after the word presentation; or one hour before the retention test. (Actual cortisol concentrations in saliva were comparable to levels produced naturally in response to a major stressor.)
         
Compared to the placebo, the cortisone pills impaired memory – but only when they were taken an hour before the recall test that was given on the next day. Therefore, high levels of this stress hormone impaired memory, but only when people tried to recall old, not recent, memories.

IThe growth of new brain cells – a process called neurogenesis – is involved in new memory formation. Researchers at Princeton University report that, even in adulthood, thousands of hippocampal neurons were being generated per day.

In animal studies, the number of adult-generated neurons in the hippocampi of rats doubled after they performed specific behavioral tasks and training that involved associative learning. In contrast, tasks that did not require the hippocampus did not stimulate new cell growth.
         
"All of the species we examined showed evidence of substantial neurogenesis in adulthood," Princeton's Elizabeth Gould said. "These findings indicate that adult-generated hippocampal neurons are specifically affected by, and potentially involved in, associative memory formation."

2 comments:

  1. Deep breaths and count to ten :) Then drive to NC to visit me!!!

    ReplyDelete
  2. Very informative, about the disease and about your life living with it. The pool, the margaritas and Kroozer sound like a great stress reducer combo.

    ReplyDelete