Alzheimer's: A Mensa Bulletin Perspective - On Avoiding It, Recognizing It

For those of us over 65s, the specter of Alzheimer's disease stalks us as if from the shadows. - as we understand that after the age of 65 the incidence of the disease doubles every five years.  The most recent relative actually diagnosed with it was Janice's cousin Desmond - once a man of quick wit and endless curiosity, especially about astronomy and cosmic physics. In the photo image shown we'd just been discussing dark energy and he attended a lecture I gave that evening at the Harry Bayley Observatory. Of all the  30 or so attendees, he asked the most percipient questions. 

By the time we visited Barbados in May, 2010,  we were told Desmond was in a "home" - where he was being cared for. We went to see him, unable to believe a man of such intellect could be reduced to little more than a babbling baby - but it was true. The experience shocked us both and made us even more wary of the disease. Little lapses in memory somehow transmogrified into real fears of disease onset, not to mention other lapses - i.e. such as in a blog post two days ago putting "Frogs" in the header instead of "pigs".  Alzheimer's? Or just a transitory brain fart arising from overload?

Fortunately, a Mensa Bulletin article, 'Understanding Alzheimer's', by Edna R. Tynes (February, 2014, p. 18) sheds much needed light.  Perhaps the most important contribution is the recognition of the disease apart from normal aging.  The lapses in memory, in particular, are well -explained:

"Normal aging is what happens when your brain gets overloaded. It's not so much that your brain can't collect and store memories, it's the fact that the mechanism in the hippocampus that indexes your memories and decides where to store them gets overloaded. It's the overload of this index that slows down your ability to recall and use a particular memory - also known as 'senior moments'."

This makes eminent sense given people who've lived 60 or more years have millions of memories stored, far more than a high school or college grad. As each new experience unfolds, including learning, more and more 'blocks' of memory are added to the hippocampus' indexes.  One can in some ways think of it as a "register problem".  As registers become overloaded with gigabytes of information and past events they become ever more difficult to access. This is why seniors take longer at many different tasks, because even when they are thinking them through to answer questions -  they are going into the vast store of prior learning. This is also why, as the author observes, "the ability to learn new things and retain that knowledge tends to decrease with age."

This is one reason I blog, and do diverse posts on many different topics apart from my specialty areas of astrophysics, modern physics and advanced math. Writing a blog post on a topic in economics, or medical research, or politics forces one to become familiar with it by doing research, or reading specific articles. Also, having written a blog post on some topic, all I need to do is recall the gist of it or a keyword to immediately bring it up via Google. In that way I can keep the memory of what I wrote fresh in mind.

I am still able to do the same with most books. Although I may not be able to recall a specific issue, or what was discussed in a particular text, I am able to immediately find the book in my library and locate the page of interest.

There are other ways the author suggests for delaying or avoiding the disease:

-  Frequent use of puzzles or games, particularly strategy games (GO, Chess)

-  Reading, especially non-fiction (history, politics, economics, science)

- Socializing, especially in venues where the conversation is stimulating.

- Traveling and learning a new language (or keeping up with one you took in college)

- Taking classes in something new, either in a classroom setting or online - anything to exercise your mind.

- Eating more fruits and vegetables as part of a healthy diet

- Maintain low cholesterol and blood pressure

- Avoid Type 2 Diabetes

All of these are quite doable but clearly some more so than others. The point is that at all costs one want to keep one's mind active and sharp. Some may do it by working out calculus problems from one's college textbooks, while others may read and research historical topics, or venture into the realms of deep politics or quantum physics.

What about the warning signs of Alzheimer's? A number of them are listed in the article and which those who note them might wish to attend to:

1- Memory loss. Not senior moments, but forgetting recently learned information and major events. (I.e. you forgot that the U.S. was planning an attack on Syria last July-August)

2- Decreased Problem solving skills - watch out if you take longer to complete common tasks or have difficulty with math problems you once found easy.

3- Time and date confusion: difficulty understanding the passage of seasons, not knowing the year or why events don't happen immediately.

4- Difficulty with familiar tasks: Beware if you no longer remember the way to work, can't remember a problem protocol - or how to play Hearts.

5- Vision and spatial understanding: Difficulty judging distances, color contrasts or even reading.

6- Communication issues: Difficulty with joining or maintaining conversations - repeating the same points all the time - or expressing oneself. Including in expressing your ideas in writing.

7- Losing items: Everyone misplaces keys or pens on occasion but putting things in odd locations (e.g. the car keys in the fridge) is a red alarm. (Also accusing others of taking the lost items).

8- Abnormally bad judgment: Being frivolous with money, i.e. buying 150 Publishers Clearinghouse magazine subscriptions a year to win their 'sweepstakes', or 100 lotto tickets a day. Making unsafe decisions or lapsed grooming habits.

9- Withdrawal. Pulling away from family and friends is a warning sign, as well as foregoing hobbies and beloved activities.

10- Mood changes: Becoming paranoid or abnormally suspicious about others' behavior - or becoming angry,  depressed or anxious for no reason.

Of course, there is now a blood test to identify Alzheimer's with relatively high probability (AARP Bulletin , 'Would You Want to Know?', May, p. 20)  but with no clear means of effectively addressing the disease or treating it, what would be the point?  Craig Klugman, a bioethicist quoted in the article, observes:

"A positive result on a test like this could be devastating. It could change people's outlook on life, making them anxious, depressed and withdrawn. Suddenly, you find yourself living with this sense of doom that can effect every dimension of your life."


Image from Mensa Bulletin, February, p. 21.

Those who test positive could also suffer the added burden of feeling stigmatized or ashamed. You know you have this defect of the brain and now that you have this knowledge which eats away at your confidence, choices and words. As each new lapse, or faux pas occurs, the stigma is reinforced and the affected person becomes more withdrawn. Soon he identifies with the disease and it becomes his very manifestation. 

Nor is this empty speculation. A recent study cited in the AARP article (ibid.)  looked at the effect of telling people that they carry a genotype that puts them at high risk of developing Alzheimer's. Those who tested positively judged their memories more critically as well as every lapse. They also performed worse on memory tests than those not informed.

Get a blood test to identify Alzheimer's bio-makers ahead of time? Nope. Until viable treatment options exist there's no point in knowing.  But at least articles such as the one in the Mensa Bulletin make one more aware of the disease - recognizing warning signs without a blood test and how one might try to avoid becoming a victim by being pro-active.

Why Is Human Memory So Variable and Subjective?

I can mobilize an eidetic recall of the events at my last party in my apartment in New Orleans in May, 1969 (including the brew I was drinking), and yet a brother who visited me with a friend can't recall even being there. (I showed him the photos, and told him he was the one taking them.)  How is it I can recall this event including that he was there, in person, doing the photography, but he can't?

How is it that other events also may slip off the memory grid for him, and not for me, and in other cases slip off my memory grid but not his?  How is it my wife can exactly recall a movie we went to a year ago, but I can't? How is it I can recall exactly where my wife and I ate at Dallas-Ft. Worth airport in May, 2003 - while in transit to Barbados -but my wife can't?

All these questions and more occurred to me lately, and I began to inquire into why human memory is such a fragile, imperfect, subjective and variable thing. What we do know is that the hippocampus (named after its resemblance to the seahorse, from the Greek hippos meaning "horse" and kampos meaning "sea monster") plays important roles in the consolidation of information from short-term memory to long-term memory and spatial navigation. The hippocampus is located under the cerebral cortex . In primates it is located in the medial temporal lobe, underneath the cortical surface. It contains two main interlocking parts: Ammon's horn and and the dentate gyrus.

In Alzheimer's disease, the hippocampus is one of the first regions of the brain to suffer damage; memory loss and disorientation are included among the early symptoms. Damage to the hippocampus can also result from oxygen starvation (hypoxia), encephalitis, or medial temporal lobe epilepsy. People with extensive, bilateral hippocampal damage may experience anterograde amnesia—the inability to form or retain new memories.

In the case of Janice's cousin Desmond,  who died of Alzheimer's disease two years ago, the first memories lost were of distant events - while he retained memories of more recent ones. This is actually in contrast to how the disease usually presents, with long past events much more easily recalled than recent ones.


But let's leave out Alzheimer's and simply ask why memory varies so much in normal people, and how it is we differ so markedly in what events we can recall.  Some hints were presented in the Scientific American article 'The Language of the Brain' (October, 2012). What we learn is interesting to say the least.  This is in terms of "sequences of synchronized spikes"  in the particular cortical region to enable a critical factor in perception and memory.

As the article observes (p. 59):

"It appears that such synchrony acts to emphasize the importance of a particular perception or memory passing through conscious awareness."

In addition, evidently the degree to which we pay attention determines the frequency of the synchronized spikes in the 'gamma band' of frequencies (30 - 80 Hz).  The higher the frequency, the more numerous the synchronized spikes, the better a memory will be recalled. Further, gamma band signaling between distant cortical areas is also involved - as discovered by Pascal Fries of the Ernst Strugman Institute for Neuroscience.

Another interesting aspect of subjective memory I've found is that in places where I've actually lived over time I have much better memories of events than for the odd times I visit other locations - for relatively brief times. In the latter case, my memory is often patchy and unreliable. This is one reason whenever I travel now I keep a daily journal of events. In this way I can easily grab a journal kept over any past vacation, or brief interlude, and see what happened on such and such a day without having to play craps with my memory. (Which I admit is variable: excellent and eidetic in some realms and not so much in others!)

Research by Margarita Behrens of the Salk Institute - cited in the article - has also traced signal deficits to a neuronal cell called a "basket cell" - which is involved in synchronizing spikes in nearby circuits. An imbalance of either inhibition or excitation of these basket cells can then lead to reduced synchronized activity in the gamma band. Interestingly, this anomaly can also indicate neurological disorders such as autism and schizophrenia. These circuit anomalies may also be responsible for the thought disorders that often accompany schizophrenia.

We also learn (ibid.):

"When it comes to laying down memories, the relative timing of spikes seems to be as important as the rate of firing. In particular, the synchronized firing of spikes in the cortex is important for increasing the strengths of synapses- an important process in forming long term memories."

A synapse is "strengthened" whenever the firing of a neuron on one side of a synapse incites the neuron on the other side to register a stronger response. See e.g. the diagram below:

















How critical is this timing aspect? In 1997, researchers at the Max Planck Institute for Medical Research in Heidelberg, Germany,  found that a 20 milliseconds variance is all that's needed to throw a memory off. Thus, assuming a frequency in the gamma range, if an input at a synapse is consistently followed - within 10 milliseconds- by a spike from the neuron on the other side, then the memory is likely sealed. However, if the converse occurs, i.e. the neuron on the other side fires 10 milliseconds before the first one  all bets are off. The strength of the synapse between the cells decreases and the memory is then either fuzzy or lost.

The article ends by noting: that some of the strongest evidence that synchronized spikes may be important for memory comes from research by Gyorgy Buzsacki of New York University on the hippocampus. He found that the spiking of neurons in the hippocampus and other cortical regions it interacts with is strongly influenced by synchronous oscillations of brain waves in a range of frequencies from 4 to 8 hertz (the theta band). It seems that these theta band oscillations can coordinate the timing of spikes and have a "more permanent effect on the synapses."

This means the memory produced will be more long term, and better, more reliable.

In the end, memory is seen to be very dependent on synapse strengths and synchronization of specific types of waves (gamma and theta bands). If any one element is missing or off, then the memory simply can't be depended upon to yield accurate information - or maybe any information.

The moral of the story is that if we intend to trust our memories we better have those which resemble  the "memory masters" who possess the ability to recall what events happened on every day of their lives, e.g.
http://www.dailymail.co.uk/health/article-1340162/Memory-masters-The-people-rememberl-exactly-happened-day-lives.html

Failing that, we better learn to keep meticulous journals or take photographs of every major event we attend!

As for the key question: Why can't I remember that? The fault may not lie in one's 'stars' but in his synchronous spikes in the gamma band!