Chapter 3: Neurodegenerative disorders:
Neurodegenerative disorders are disorders that involve progressive loss of
function or destruction of neurons or various structures of the brain.
Acquired disorders is caused by an accident, insult or disease process coming
from a source outside of the cortex.
In order to make diagnostic sense out of the behavioural patterns that emerge in
neuropsychological assessment, the practitioner must be knowledgeable about the
neuropsychological presentations of many kinds of neuropsychological disorders
and their underlying pathology.
Example: The distinction between dementia and depression.
Dementia and depression may reflect sadness, concentration and attention
difficulties, vegetative signs such as sleeping and eating difficulties and other
However, the causal factors are clearly dissimilar and require very different
treatment plans and rehabilitation strategies.
involves difficulties with destruction of neurons and/or specific areas within the
The loss of neurons or neural tissue is not repairable and the loss of abilities is
The etiological factors are unknown for many of the degenerative disorders.
Often occurs in the older population.
damage within the cerebral cortex, which leads to symptoms of dementia.
Demonstrates a progressive decline in cognitive abilities.
Memory and other higher order of cognitive abilities lost with dementia.
As the disease process progresses, patients with different etiologies tend to show
many similar symptoms, which often makes the diagnosis more difficult.
Many of these difficulties eventually become neuropsychologically
Dementia is usually described in reference to behaviours falling within 3 stages.
Stage 1: involves behaviours that may deviate from the norm for the individual.
The individual himself/herself may not be aware of the changes at this time.
Examples of stage one symptoms would be small changes in personality or
memory lapses noticed by the individual’s friends and family.
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
As stage two progresses, the individual become geographically lost or wander and
may engage in activities which are dangerous to self or others. Sundowning: in patients with dementia, the worsening of symptoms as the day
This begins during stage two.
Families of the of individuals with dementia usually begin to consider placement
in treatment facilities such as nursing homes during stage two.
Stage three involves serious cognitive deterioration in addition to problems
associated with selfcare.
Many families find that an individual with stage 3 dementia requires care outside
of the family environment.
Patients with stage 3 dementia may be unable to toilet, dress, or feed themselves,
however these symptoms are quite variable between individuals.
The most frequent cause of death for patients with dementia is pneumonia.
Dementia affects approximately 58% of the population older than the age of 65,
and 2550% of individuals 85 years and older.
Alzheimer’s Type Dementia:
The most common form of cortical decline is Alzheimer’s type dementia.
The term Alzheimer’s disease was first used by Alois Alzheimer in 1906.
A clear diagnosis of Alzheimer’s disease cannot be made without an autopsy.
Alzheimer’s disease is characterized by neurofibrillary tangles and amyloid
Neurofibrillary tangles are made from tau proteins and develop when
microtubules, which transport substances from the soma to the end of the axon,
Tau is the protein which maintains the microtubule’s structure, but in Alzheimer’s
disease it is altered, which allows the twisted microtubules to group together into
The volume of these tangles obstructs living tissues and often strangles it.
The amyloid plaques were referred to as cellular trash.
We now know that they plaques are made of an amino acid peptide protein core
termed betaamyloid, hence the term amyloid plaque.
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 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
Apo E is a normally occurring protein that helps carry phospholipids and
cholesterol within the body.
This gene has three types:
The E4 allele type has been linked by researchers to various disorders including
Down syndrome is the most frequent cause of mental retardation and is caused by
a trisomy on chromosome 21.
Cognitive features are severe verbal memory difficulties. The memory loss begins slowly in the first stages of the disorder and progresses
to severe in the end state.
Red wine is good for prevention. It contains Antioxidants.
Treatment for cognitive deficits is usually with anticholinesterase inhibitors that
enhance cholinergic function.
degenerative disorders of the frontal and temporal lobes with the remainder of the
cortex maintaining relative integrity.
FTD and Alzheimer’s disease are extremely similar, in later stages, almost
Changes in social behavior and personality, lack of insight and stereotypic
behaviours such as the repeating of a behavioral sequence, and eating a great deal
of food, best differentiate frontotemporal dementia patients from those with
Other common features of FTD include speech and language changes,
extrapyramidal symptoms, and primitive reflexes.
It was also termed Pick’s disease
Pick’s disease is now thought to be a subtype of FTD.
The difference which sets Pick’s disease apart from other FTDs, is the presence
od Pick bodies comprised of tau proteins, which are shaped differently than the
neurofibrillary tangles seen in Alzheimer’s disease.
Dementia with Lewy Bodies:
Dementia with Lewy bodis accounts for approx. 20% of patients with dementia.
Symptoms include progressive dementia, extrapyramidal signs similar to
Parkinson’s disease, visual hallucinations, delusions, and possibly severe
Patients with DLB frequently have an elevated ApoE4 Allele.
More common in men usually occurring after the age of 50.
These patients have a more rapid decline than other patients with dementia.
Individuals with DLB have shown improvement in cognition and behavior using
dementias that affect subcortical brain structures.
The distinction between cortical and subcortical dementia is largely behaviourally
The behavioral changes that differentiate subcortical dementias from cortical
dementias include cognitive slowing with problems in attention and
concentration, executive disturbances including impaired concept manipulation,
visuospatial abnormalities, and memory difficulties that affect retrieval more than
Absence of aphasia (loss of expressive or receptive language), apraxia (inability
to perform purposeful movements), and agnosia (inability to recognize sensory
input). Emotional features include apathy, depression, and personality change.
Disabilities related to arousal, attention, processing speed, motivation, and
emotion, as opposed to the involvement of higher order functioning as in cortical
a movement disorder with attendant symptoms.
Symptoms include shaking, lessened muscular power, difficulty moving from
resting to walking and vice versa, a tendency to bend forward while walking, and
cognitive and emotional sequelae.
Another classic symptom is the lack of facial expressions.
Depression is one of the most common symptoms of PD with estimates ranging
from 4060% of patients.
Parkinson’s disease is associated with the depletion of the neurotransmitter
dopamine in the basal ganglia, subthalamic nucleus, substantia nigra, and the
interconnections to each other and to thalamic nuclei.
It typically affects individuals in their 50s.
LDopa began to be used for the aforementioned issues in 1967 to replace
dopamine depletion in the substantia nigra.
Anticholingeric medications: deal with motor symptoms but have an adverse
effect on selective attention and planning.
another form of subcortical dementia
Once termed Huntington’s chorea
The spasmodic symptoms are very blatant and ivolve involuntary movements that
become disabling because of their severity.
Also has cognitive and personality impairments.
Wexler describes this disease as the most diabolical disease known to mankind
during a PBS brain series video.
It is anatomically caused by atrophy of the GABAergic neurons of the caudate
nucleus and putamen in the corpus striatum.
GABA is the most common inhibitory neurotransmitter.
The atrophy may also affect the cerebellum, thalamic nuclei, and other subcortical
It is a steadily progressive disease.
Tends to affect people anywhere between 1020years of age.
As the disease runs its full course, pneumonia is the most common cause of death.
This is a hereditary condition.
It is caused by an excess number of trinucleotide CAG repeats on chromosome 4.
Occurs more frequently in Caucasians than in African Americans and is rarely
observed in Asians.
Neuroleptic medications are most often used to deal with the spasmodic
Progressive Supranuclear palsy Progressive supranuclear palsy is a subcortical dementia also known as Steele
The classic feature of this disorder is an inability to look downward on command.
The progression of cognitive decline appears to be greater than in the other
disorders already described and is consistent with degeneration of both cortical
and subcortical region.
Upper brain stem to the basal ganglia and may include the limbic structures and
the basil ganglia (cortical atrophy).
The degenerative process appears to disconnect ascending pathways from these
structures to the prefrontal cortex.
Usually develop in one’s 60s.
The emotional symptoms may be treated with anti depressants.
Progressive disorders of the CNS:
a disease caused by the destruction of the myelin sheath which covers the axons
Classic symptoms include: weakness, stiffness, lack of coordination, gait
disturbances, bladder and bowel difficulties, sexual dysfunction, sensory changes,
heat sensitivity, and fatigue.
Intellectual functionally is significantly affected in about 20% of patients, and
memory is one of the most commonly affected areas.
Emotion sequelae are also evident and many patients will experience denial of
their symptoms even when they become wheel chair bound or bedridden.
MS is characterizes as a relapsing and remitting disorder.
It often exhibits static periods where the progression ceases but the lost functions
are never regained.
MS tends to follow one of several courses, these are:
*Relapsing remitting: most common; characterized by clearly defined disease
relapses. Recovery can be full or with sequelae and residual deficit. No
progression of disease between relapse.
•Second progressive: the next most common. Fir