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Chapter 3

PSYC32H3 Chapter Notes - Chapter 3: Vasoconstriction, Anaplasia, Idiopathy


Department
Psychology
Course Code
PSYC32H3
Professor
Zachariah Campbell
Chapter
3

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PSYC31H3 Week 2 Notes on Chapter 3
Introduction:
Neurodegenerative disorders: Disorders that involve progressive loss of function or
destruction of neurons or various structures of the brain.
Acquired disorders: Disorders caused by an accident, insult, or disease process coming
from a source outside of the cortex.
Knowledge of the various difficulties which an individual may sustain is crucial for a
clinical neuropsychologist. The roles of conducting assessment, applying a diagnosis,
and undertaking treatment all require the professional to have a working understanding
of the various ailments, their etiology or causal factors, if known, course of illness,
prognosis, and rehabilitation.
Another reason why it is necessary to understand the clinically presented symptoms and
the causes of various disorders is that, very often, dissimilar difficulties present
themselves with similar symptomology. A common example is the distinction between
dementia, with its multiple causes, and depression. Both dementia and depression may
reflect sadness, concentration and attention difficulties, vegetative signs such as
sleeping and eating difficulties and other similar symptoms. However, the causal factors
are clearly dissimilar and require very different treatment plans and rehabilitation
strategies.
Another factor to consider is that the majority of central nervous system diseases or
difficulties involve depression as a secondary symptom, which suggests that it is a
reaction to the primary diagnosis.
Degenerative Disorders:
By the nature of the term, degenerative disorders involve difficulties with destruction of
neurons and/or specific areas within the central nervous system. In many of these
difficulties, the loss of neurons or neural tissue is not repairable and the loss of abilities
is permanent. The etiological factors are unknown for many of the degenerative
disorders. These disorders tend to occur more often in the older population and as the
population as a whole ages, more and more of these disorders are surfacing.
Cortical Dementias:
Cortical Dementia refers to damage within the cerebral cortex and demonstrates a
progressive decline in cognitive abilities. Memory and other higher order functions such
as reasoning and the ability to do abstract through are examples of the types of cognitive
abilities lost with dementia.

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Dementia takes a downward course with the result being the death of the individual.
During the early stages of degenerative disorders, differences usually appear. As the
disease process progresses, patients with different etiologies tend to show many similar
symptoms, which often makes the diagnosis more difficult.
Dementia is usually described in reference to behaviours falling within three stages.
Stage one involves behaviours that may deviate from the norm for the individual.
The individual himself or herself may not be aware of the changes at this time.
During stage two of dementia, the individual often notices memory problems and
tries to conceal them from others. Confabulation may occur, similar to individuals
who consume large amounts of alcohol, in which the individual develops a cover
story or excuse for the lack of memory. As stage two progresses, the individual
may become geographically lost or wander and may engage in activities which
are dangerous to self and others.
Sundowning: In patients with dementia, the worsening of symptoms as
the day progresses.
Stage three involves serious cognitive deterioration in addition to problems
associated with self-care. Many families find that an individual with stage three
dementia requires care outside of the family environment.
Individuals usually do not die from dementia, but from some others opportunistic agent
which invades a nonintact central nervous system. A central nervous system that has
significant impairment in neurological tissue is not able to fight off viruses or any other
invading process as a full intact central nervous system.
Alzheimer’s Type Dementia:
Alzheimers Type Dementia: Dementia characterized by neurofibrillary tangles and
amyloid plaques; a diagnosis cannot be made until autopsy but is termed Alzheimer’s
type based on behavioural symptoms.
Alzheimer’s disease is characterized by neurofibrillary tangles and amyloid plaques.
Neurofibrillary tangles are made from tau proteins and develop when microtubules,
which transport substances from the soma to the end of the axon, become twisted. Tau
is the protein which maintains the microtubules’ structure, but in Alzheimer’s disease it is
altered, which allows the twisted microtubules to group together into tangles. The
volume of these tangles obstructs living tissue and often strangles it.
Amyloid Plaques: Deposits of aluminum silicate and amyloid peptides believed to cause
loss of neurons and vascular damage.
These plaques also obstruct living tissue. It is important to note that the plaques and
tangles appear in normally aging individuals and individuals with other degenerative
diseases. The key to a diagnosis of Alzheimer’s disease is the extent of the tangles and
plaques and the regions of the brain they gravitate toward.

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Loss of neurons is another common feature of Alzheimer’s disease, particularly in the
temporal area. If neurons are no longer able to communicate with major memory areas
within the cortex, significant memory loss may occur.
Loss of neurons also leads to changes in anatomical structures, which may point to the
enlargement of ventricles with Alzheimer’s disease.
Alzheimer’s disease has an inherited genetic component. If an individual has a first-
degree relative (parent or sibling) with the disease, it doubles the person’s chances of
acquiring the disease compared to those without affected first-degree relatives.
The other three well-established risk factors for Alzheimer’s disease are age, the gene
for the protein apolipoprotein E (Apo E) on chromosome 19, and Down syndrome. Apo E
is a normally occurring protein that helps carry phospholipids and cholesterol within the
body, the E4 allele has been linked to various diseases such as Alzheimer’s disease.
Allele: Any one of a number of viable DNA codings that occupy a given position on a
chromosome.
Down syndrome is the most frequent cause of mental retardation and is caused by a
trisomy on chromosome 21. Almost all individuals with Down syndrome show mental and
physical deterioration characteristic of Alzheimer’s disease if they live longer than 30-40
years.
Additional causes of Alzheimer’s disease have been investigated but are controversial.
Traumatic brain injury is one suspected precursor to Alzheimers disease. It appears that
the more serious the injury, the more likely it is the individual will develop Alzheimer’s
disease.
A low level of estrogen in postmenopausal women is another theory which has been
proposed for Alzheimer’s disease.
Treatment for Alzheimer’s disease may involve preventive measures such as drinking
red wine, which contains antioxidants that may have a protective effect. Medications
which stop the development of amyloid plaques have been developed. Other
medications that keep tau in its normal form have also been explored.
Frontotemporal Dementias:
Frontotemporal dementias (FTDs) are degenerative disorders of the frontal and temporal
lobes with the remainder of the cortex maintaining relative integrity. These difficulties
have a slow onset and progression. The age of onset is usually between 40 and 65
years of age.
The symptoms of FTD and Alzheimer’s disease are extremely similar and, in later
stages, almost indistinguishable. Changes in social behaviour and personality, lack of
insight and stereotypic behaviours such as the repeating of a behavioural sequence, and
eating a great deal of food, best differentiate frontotemporal dementia patients from
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