MEMORY LOSS CAUSED BY ALZHEIMER’S AND THAT BY AGING
Introducing the Difference between
Memory Loss Caused by Alzheimer’s and That by Ageing
With the Aid of the Published Experiments
Jenny (Jae-Eun) Chang
85102 Introduction to Psychology
1
MEMORY LOSS CAUSED BY ALZHEIMER’S AND THAT BY AGING
2
Abstract
The consequences of having Alzheimer’s disease are devastating. It is a brain
degenerative disorder characterized by the loss of neurons and synapses and damages in brain
areas which are responsible for cohesive cognition. However, in the beginning, it only appears as
occasional mistakes humans are bound to make, such as minor and inconsequential forgetfulness.
The dementia is also hard to detect because it is prominent among elderly and the symptoms are
almost indistinguishable from the deteriorations caused by ageix n mhng to the uninformed
majority. It is very likely to proceed to the uncontrollably severe stage unnoticed. One measure
to prevent the symptoms from exasperating is to discover ways to make the disease more visible
to the general public. Memory is something most people can test themselves. Taking this
convenience into account, this paper explores the simple task of introducing the difference
caused by ageing and that by the dementia found in various experiments to aid to the complex
task of facilitating the battle against this disease.
MEMORY LOSS CAUSED BY ALZHEIMER’S AND THAT BY AGING
3
The beginning of Alzheimer’s disease feels like healthy ageing. An inflicted patient
shows signs of memory degeneration but laughs it off, claiming he must be getting old. Because
the symptoms for the disease at a mild stage is similar to those unavoidable with aging, he
overlooks the problem until accidents become frequent and when he, finally, finds his behavior
strange he is already at a stage where his cognition and other controls of his mind are undergoing
dreadful alterations. Alzheimer’s disease is a brain degenerative disorder characterized by
anatomical changes such as neocortical atrophy, neuron and synapses loss, and damages in
various parts of the brain including hippocampus and entorhinal cortex (Salmon, Butters, &
Chan, 1999). The disease starts off very mildly resembling the normal symptoms of healthy
aging in many ways. However, with increasing acuity, it deteriorates one’s mind so much that,
instead of making worthwhile last memories, it retrogrades in memory and meets an unready end.
It is important we learn the differences between healthy aging and Alzheimer’s so that, upon
recognizing the disease early on, we take precautions to prevent further exacerbation. The most
distinguishing symptom of the dementia is memory loss. Fortunately, memory is an easily
detectable measure and, therefore, it is the best means of diagnosis besides professional advising.
The experiments performed on this topic clear some of the misconceptions of the disease and
discern more accurately the memory loss caused by the dementia from that by aging.
The Wechester Memory Scale has conducted a great number of studies to show the
detrimental role of Alzheimer’s in memory. The Logical Memory subtest of the Wechester
Memory Scale remains so far the most extensive neuropsychological battery done to study
whether semantic deficiency is the most noticeable symptom of Alzheimer’s. Arriagada,
Growdon, Hedley-Whyte, and Hayman produced recent studies, suggesting that the
hippocampus which is responsible for producing semantic memory is involved in the earliest
MEMORY LOSS CAUSED BY ALZHEIMER’S AND THAT BY AGING
4
stages of the disease (as cited in Salmon, et al., 2002, p.108). Supportive of their view, Haut,
Demarest, Keefover, and Rankin (as cited in Johnson, Storandt, & Baloa, 2002, p.82) claimed
that although able to use correct grammar, Alzheimer patients lack coherent thought process
necessary for articulating thematically ideas, a sign of semantic deficiency.
Their study accurately presented what this deficiency meant. It was conducted carefully
to eliminate any subjectivity and ambiguity in scoring. For prose recall, texts were divided into
propositions, the smallest phrases or words that retain meaning relevant to the concepts present
in the text as a whole. Questions referred to central concepts and arguments, asking who and
details on the actors or actions, respectively. The goal was to determine if the subject grasped the
thematic concept, to test the participant’s semantic memory ability. Full score was given when
the answer contained veridical report establishing some relationships, not necessarily the exact
replica of the original text. Some points were allowed for gist production, reproducing the text’s
intended meaning but no veridical report, and distortion of the text. The subjects of the study
were blocked into four groups: adults who are young, healthy old, with no dementia, very mild
dementia, and mild dementia. The three older groups had only slight age variation, all of their
age centered at about early seventy. The participants were asked to recall twice: immediately and
thirty minutes after hearing. They were not informed about the second testing and were carefully
monitored to reduce the effect of interference as much as possible (Johnson, et al., 2002).
The result for the immediate recall is astounding. Although our experience or common
sense says otherwise, there was no significant difference between the ages for the veridical
response. Semantic memory, an ability to memorize through association with meaning and
concept, does not diminish with increasing age when used for short-term. Morris suggests that
many researches done in the past may have produced wrong results that attributed immediate
MEMORY LOSS CAUSED BY ALZHEIMER’S AND THAT BY AGING
5
memory loss to ageing because they have failed to screen their older subjects for dementia and,
therefore, failing to account for the effect of dementia (Johns, et al., 2002). The only influence
the increase in age had in the immediate questioning was that it reduced the number of distortion
(Johns, et al., 2002). This prominence of distortion for the young generation, although not
mentioned in the WMS Logical Memory, is due to false recall, possibly caused by ample
neurological synapses promoting learning and forming new associations.
In a delayed retrieval, however, age has a significantly more noticeable effect. Older
participants proved to have much more difficulty retaining veridical representations than young
adults. Breakdown in retention in the long run and the immediate memory loss of dementia are
often mistaken for one another.
The effect of dementia is evident in recalling gist and veridical responses. The more
severe the dementia the smaller the number of veridical and gist recalls were. Although the gist
response also decreased by a noteworthy amount the immediate decrement in veridical response
is significant enough to be the most distinguishable feature of the dementia in immediate recall.
The effect of dementia after delay is only a little different from that of before. The number of
gist recall and distortion remained low. Johnson (as cited in Johnson, et al., 2002, p.89)
concludes that the error committed by the demented participants is from omission rather than
commission. Moreover, upon further analysis, it is found that under gist error central association
was remembered a great deal more than arguments. This raises another possibility that although
semantic deficiency was responsible for the dramatic decrease in veridical response their ability
to make associations prove that the semantic priming is not completely absent; there may be
another mechanism underlying the memory loss (Johnson, et al., 2002).
MEMORY LOSS CAUSED BY ALZHEIMER’S AND THAT BY AGING
6
Baddeley (as cited in Johnson, et al., 2002) proposed another explanation for memory
loss in demented participants with the introduction of episodic buffer which is a temporary
storage system controlled by the central executive, which does not have storage capacity but
governs attention control. He argues that the fact that recent memory, intact comprehension,
retention, and other integration elements remain during the early stages of the dementia serves as
a proof that semantic priming, or forming relationships for the incoming information based on
what they already know, are not lost but, relatively active and, lack of attention, instead, should
be blamed for forgetting (as cited in Johnson, et al., 2002).
Moreover, the false recall test challenges the claim that early phases of Alzheimer’s
disease are marked by semantic memory loss. False recall should only be expected from the
people who are able to encode and retrieve misinformation, or false but related information,
which can only be made through establishing some connections among inputs. Therefore, should
Alzheimer patients lack semantic priming, which allows recognizing conceptual relationships,
they will not be able to retrieve misinformation. The result was revolutionary. Alzheimer patients
successfully produced misinformation; they were told to study lists of related words such as
“thread, pin, and eye”. Then, when ordered to recall, they were able to retrieve non-presented
items that were related to the list, such as “needle”. Watson, Balota, and Sergent-Marshall noted
that this ability to contrive false but related information was consistent throughout different age
groups and multiple levels of dementia severity even though veridical recall still declined among
them (as cited in Marsh, et al., 2005, p.116). As Balota and Dutcheck claimed, this regularity is
not possible unless the individuals at the early stages of the dementia preserve semantic priming
and some other semantic associating processes that are inaccessible via explicit retrieval but
available through other means(as cited in Marsh, et al., 2005, p. 116).
MEMORY LOSS CAUSED BY ALZHEIMER’S AND THAT BY AGING
7
As an additional evidence to the strength of the semantic activation, Budson, Daffner,
Desikan, Schacter, and Sitarski demonstrated that the demented individuals were unable to
reduce an illusion made by false connections even with episodic information, repeated study
trials, and picture presentation of associates (as cited in Marsh, et al., 2005, p.116). This proves
how strong the relationships were established and since their semantic priming seems to be
firmer than their memory retention the associations made were hard to break by exposing them
other memories. Interestingly, this aspect of the dementia is similar to the symptoms of healthy
aging. Older adults were exposed to an original event and then also misled about it (Marsh, et al.,
2005, p. 115). The result showed that they were much more prone to reproducing misinformation
after they were corrected than young adults. They also showed signs of impaired episodic
memory in tests to recall the scenes of the movie they just watched (Marsh, et al., 2005). Here,
we learn what we know to be a slight difference between the healthy old men and the mildly
demented actually subtler. However, the difference exists – although they both intact semantic
priming and make inflexible connections among related subjects, the demented patients are
inexplicit, drastically lacking in veridical articulation for the connected they established in their
heads, and, therefore, in complicated tasks such as explaining thematic ideas they appear as if
they could not catch any main point.
Furthermore, the experiment advanced into a different study in order to investigate
whether reading about a story with lies and truths would lead them to use the information they
gathered from the reading when they are tested later on general knowledge. The same study was
provided to both groups of interest. Learning false or facts they did not know about required
them to form new associations. The Alzheimer patients recalled thirty minutes later forty percent
of the information and the old adults remembered eighty-one percent even after an hour (Marsh,
MEMORY LOSS CAUSED BY ALZHEIMER’S AND THAT BY AGING
8
et al., 2005). When the test was divided into easy and difficult levels, for healthy elders,
misinformation reduced their correctness for easy questions while the reading had no affect on
them for the neutral baseline. For the demented patients, however, there was not much change
caused by the reading. This difference is caused by the healthy men’s better ability to make
entirely new associations arisen completely independent of the knowledge they previously held,
and, the demented individuals’ lack of them. For some easy questions, the patients did much
better than they did for hard ones. Marsh (2005) claimed that this was caused by their familiarity
with the easy questions. She (2005) also suggested it could have been because of their need for
longer retrieval times. However, even if she is right it proves the ability to form entirely new
connections is much harder for dementia patients than healthy elders.
Without analysis it is almost impossible to notice the difference in memory loss caused
by healthy aging and Alzheimer’s disease. The difference is small but distinguishable enough to
be a criterion for diagnosis. Short-term memory loss in veridical recall has to be dramatic. The
patient’s recalling misinformation proves that semantic priming is still retained at the early
stages of dementia, allowing making connections possible. Although the ability to create
association exists in both groups it is much harder for the demented patients to form associations
based on completely new ideas. Horrible illnesses like Alzheimer’s feel far away. Even though
as we age we show symptoms similar to the Alzheimer’s the thought of being diagnosed with it
sounds so mythical it never crosses our minds. However, it is a prominent disease killing
growing number of lives. Instead of taking comfort in the benefit of the doubt, one must tighten
the loose assumptions and really seek to fight the dangers of the dementia from the beginning.
MEMORY LOSS CAUSED BY ALZHEIMER’S AND THAT BY AGING
References
Johnson, D. K., Storandt, M., & Balota, D. A. (2003). Discourse analysis of logical memory
recall in normal aging and in dementia of the Alzheimer type. Neuropsychology. 17(1),
82-92.
Marsh, E. J., Balota, D. A., & Roediger, H. L., III. (2005). Learning Facts From Fiction: Effects
of Healthy Aging and Early-Stage Dementia of the Alzheimer Type. Neuropsychology.
19(1), 115-129.
Salmon, D. P., Butters, N., & Chan, A. S. (1999). The deterioration of semantic memory in
Alzheimer's disease. Canadian Journal of Experimental Psychology/Revue Canadienne
De Psychologie Exp?Erimentale. 53(1), 108-116.
9