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The Cognitive Disorders
Chapter Overview/Summary
The DSM-IV recognizes various cognitive disorders, including delirium, dementia,
and amnestic disorder. Typically, these disorders result from transient or
permanent damage to the brain. Chronic neuropsychological disorders involve
permanent loss of neural cells. The primary causes of brain tissue destruction
are many and varied; common ones include certain infectious diseases (such as
the HIV-1 virus), brain tumors, physical trauma (injuries and alcohol),
degenerative processes (as in Alzheimer’s disease), and cerebrovascular
arteriosclerosis, often manifested as vascular dementia. There is no simple
relationship between the extent of brain damage and degree of impaired
functioning. Some people who have severe damage develop no severe
symptoms, while others with slight damage have extreme reactions. Although
such inconsistencies are not completely understood, it appears that an
individual’s premorbid personality and life situation are important in determining
his or her reactions to brain damage. The APOE-4 genetic allele may also be
important.
Delirium is a fluctuating condition common among the elderly. It involves a state
of awareness between wakefulness and stupor or coma. It is treated with
neuroleptic medications and also with benzodiazepines. Dementia involves a
loss of function and of previously acquired skills. It has a slow onset and often a
deteriorating course. The most common cause of dementia is Alzheimer’s
disease. Age is a major risk factor for Alzheimer’s disease as well as other forms
of dementia, such as vascular dementia. Genes play a major role in creating
susceptibility and risk for Alzheimer’s disease. Genetic mutations of the APP,
presenilin 1 and presenilin 2 genes are implicated in early onset AD. The APOE4 allele of the APOE gene is also a risk factor for AD. Interestingly, substantial
numbers of MZ twins are discordant for AD suggesting that genetic susceptibility
interacts with environmental factors. Environmental factors include diet, exposure
to metals such as aluminum, and experiencing head trauma The characteristic
neuropathology of Alzheimer’s disease involves cell loss, senile plaques and
neurofibrillary tangles. Plaques contain a sticky protein called beta amyloid.
Neurofibrillary tangles contain abnormal tau protein. Alzheimer’s disease causes
a destruction of cells that make acetylcholine, a neurotransmitter important for
memory. Drug treatments for AD include cholinesterase inhibitors such as
donepezil (Aricept). These drugs help stop ACh being broken down and so make
more of it available to the brain. Amnestic disorders involve severe memory loss.
The most common cause of amnestic disorders is chronic alcohol abuse. Head
injuries can cause amnesia as well as other cognitive impairments. Retrograde
amnesia is the ability to recall events before the accident. Anterograde amnesia
is the inability to remember things since the accident.
Any comprehensive treatment approach for cognitive disorders should also
involve caregivers, who are often under a great deal of stress and have
difficulties coping. They may benefit from medications as well as from support
groups.
Detailed Lecture Outline
I. Brain Impairment in Adults
A. Diagnostic Issues
1. DSM-IV-TR presents the diagnostic coding in different and somewhat
confusing ways
2. For cognitive disorders, both cognitive problem and medical cause are listed
on Axis I; medical condition listed again on Axis III
3. Brain changes due to substances are simply placed on Axis I
B. Clinical Signs of Brain Damage
1. For most part, cell bodies and neural pathways do not regenerate
2. Impairment may involve acquired and customary skills or capacity for realistic
self-appraisal (anosognosia)
3. Impairment depends on:
a. Nature, location, and extent of neural damage
b. Premorbid competence and personality of the individual
c. Individual’s life situation
d. Amount of time since the first appearance of the condition
C. Diffuse versus Focal Damage
1. Attention is often impaired by mild to moderate diffuse damage, such as might
be expected with moderate oxygen deprivation or the ingestion of toxic
substances
2. Mild cognitive impairment can also be detected in those who have had only
low-level exposure to organic solvents and other neurotoxins
3. Focal brain lesions are circumscribed areas of abnormal change in the brain
with a number of possible consequences
4. Relationships between brain location and behavior can never be considered
universally true, however:
a. Damage to frontal areas can result in one of two patterns
(1) Behavioral inertia, passivity, apathy, and perserverative thought
(2) Impulsiveness and distractibility
b. Damage to right parietal lobe may produce impairment of visual-motor
coordination
c. Damage to left parietal area may impair language, including reading and
writing, as well as arithmetical abilities
d. Damage to certain structures within temporal lobes disrupts memory storage;
extensive bilateral temporal lobe damage can result in no new memories being
able to be stored; damage to other structures within temporal lobe can lead to
disturbances of eating, sexuality, and the emotions
e. Occipital damage produces a variety of visual impairments and visual
association deficits
D. The Neuropsychology/Psychopathology Interaction
1. Most people with a neuropsychological disorder do not have
psychopathological symptoms
2. Psychopathological symptoms not always predictable
II. Delirium
A. Clinical Presentation
1. Delirium is an acute confused state with a sudden onset and a fluctuating state
of awareness
2. Commonly find: cognitive changes such as impaired information-processing,
hallucinations, delusions, abnormal psychomotor activity (wild thrashing),
disturbances of the sleep cycle
3. May result from head injury, infection, drug intoxication, drug withdrawal, drug
toxicity
B. Treatment and Outcome
1. Medical emergency – must identify and treat underlying cause
2. Most cases are reversible
3. Treatment involves medications (neuroleptics or benzodiazepines for drug
withdrawal), environmental manipulations such as orienting techniques
(calendars, staff prompting, night lights), and family support
III. Dementia
A. Dementia
1. Decline from a previous level of functioning; onset typically gradual
2. Memory for recent events affected in early stage; with time, increasingly
marked deficits in abstract thinking, acquisition of new knowledge or skills,
visuospatial comprehension, motor control, problem solving, and judgment
3. Often accompanied by impairment in emotional control and moral/ethical
Sensibilities
4. Dementia may be progressive or static
5. Occasionally reversible if underlying cause can be treated
6. Strokes, degenerative disease (Alzheimer’s, Huntington’s, and Parkinson’s),
infectious diseases (syphilis, meningitis, AIDS), intracranial tumors and
abscesses, dietary deficiencies (B vitamins), head injury, anoxia, and toxic
substances can produce the condition
B. Alzheimer’s Disease (AD)
1. The clinical picture in Alzheimer’s disease
a. Diagnosis based on clinical assessment but can only be confirmed after death
b. Usually begins after age 45
c. Gradual and slow mental deterioration is seen with multiple cognitive deficits
d. First sign may be withdrawal from active engagement with life followed by
more self-centered and child-like thoughts and activities including a
preoccupation with functions of eating, digestion and excretion; as symptoms
become more severe may see impaired memory for recent events, “empty”
speech, messiness, impaired judgment, agitation, and periods of confusion
e. Delusions (paranoid and jealous) and a combative pattern occur in some
patients
f. Death usually comes from lowered resistance to opportunistic infections
2. Prevalence of Alzheimer’s disease
a. Problem is underestimated
b. 1% to 2% of population between 65 -74; about 25% of those over 85
c. With increasing life span problem grows in magnitude
d. Women have a slightly higher risk
e. Lower rates in Japan, Nigeria, and India suggesting role of high fat, high
cholesterol diet
f. High levels of an amino acid homocystine increases risk for AD and heart
disease
3. Genetic and environmental aspects of Alzheimer’s disease
a. Early-onset Alzheimer’s disease
(1) Progression very rapid
(2) Have identified three rare genetic mutations that can cause this (about 5% of
cases)
(a) Mutated APP gene on chromosome 21
(b) Mutated PS1 (presenilin 1) gene on chromosome 14
(c) Mutated PS2 (presenilin 2) gene on chromosome 1
b. Late-onset Alzheimer’s disease
(1) APOE (apolopoprotein) gene on chromosome 19
(a) Three alleles identified
(b) APOE-E4 significantly enhances risk for late-onset AD
(c) APOE-E2 protects against late-onset AD
(d) APOE-E4 can be detected by blood test
(e) Only 55% of those with two APOE-E4 alleles had developed AD by age 80
(2) Substantial numbers of MZ twins are discordant for AD
(3) Genetic susceptibility thought to interact with environmental factors
(4) Environmental factors include diet, exposure to metals such as aluminum,
and experiencing head trauma
(5) Exposure to ibuprofen may be protective
c. Neuropathology
(1) Senile plaques
(a) Contain a sticky substance called beta amyloid
(b) Believed that an accumulation of this substance causes
plaques
(c) Beta amyloid is neurotoxic
(2) Neurofibrillary tangles
(a) Webs of abnormal filaments within a nerve cell made up of
a protein called tau
(b) Tau may be caused by accumulation of beta amyloid
(3) Granulovacuolars
(a) Small holes caused by cell degeneration
(b) Leads to reduction in acetylcholine activity
4. Treatments and outcomes in Alzheimer’s disease
a. No effective treatment exists
b. Behavioral techniques attempt to control wandering, incontinence,
inappropriate sexual behavior, and poor self-care behaviors
c. Medications such as tacrine (Cognex) and donepezil (Aricept) that inhibit the
production of acetylcholinesterase thereby increasing the availability of
acetylcholine
d. Newest medication is Namenda that appears to regulate glutamate
e. Despite setbacks, continuing to work on developing vaccines
f. Prevention is needed
5. Treating caregivers
a. Challenging management problems as well as “social death” of the patient and
their own “anticipatory grief”
b. Caregivers are at high risk for developing depression
c. Providing caregivers with counseling and support has proven effective
C. Dementia from HIV-1 Infection
1. Snider (1983) documented that the presence of the HIV-1 virus could itself
result in the destruction of brain cells
2. May lead to the emergence of psychotic phenomena
3. Virus causes generalized atrophy, edema, inflammation, and patches of
demyelination
4. Damage may occur throughout brain but seems to be localized in subcortical
regions, notably the white matter, the tissue surrounding the ventricles, and
deeper gray matter structures such as the basal ganglia and thalamus
5. Between 30 and 60 percent of untreated patients with HIV/AIS will develop
AIDS-related dementia; with current antiviral treatment, the rate reduces to 20%
D. Vascular Dementia (multi-infarct dementia)
1. A similar clinical picture to Alzheimer’s exists; although a more varied early
picture
2. Series of circumscribed cerebral infarcts cumulatively destroy neurons over
expanding brain regions
3. Tends to occur after 50; more common in men
4. Accounts for only about 19% of all dementia cases; patients are more
vulnerable to sudden death from stroke or cardiovascular event
5. Accompanying mood disorders more common than in AD
6. “Mixed” diagnosed when patient has both vascular and AD
7. Cerebral arteriosclerosis can be medically managed to some extent
IV. Amnestic Syndrome
A. Central feature is strikingly disturbed memory or amnesia
1. Immediate recall and memory for remote events usually preserved
2. Short-term memory typically very impaired
3. Confabulation common
B. Overall cognitive functioning may remain relatively intact
C. Root cause brain damage typically from chronic alcohol use with its
associated deficiency in vitamin B1
D. Other causes include: head trauma, stroke, surgery in the temporal lobe,
hypoxia, brain infections
E. Depending on cause, may abate wholly or partially
V. Disorders Involving Head Injury
A. Traumatic Brain Injury
1. Occurs frequently affecting more than 2 million people each year in the U.S.
2. Most common cause is motor vehicle accidents followed by falls, violent
assaults, and sports injuries
3. Men aged 15-24 are at greatest risk
4. Clinical Picture
a. Three types of injury are distinguished
(1) Closed head
(2) Penetrating
(3) Skull fracture
b. Immediate acute reactions such as unconsciousness and disruption of
circulatory, metabolic, and neurotransmitter regulation
c. Retrograde and anterograde amnesia are commonly seen
d. Person typically passes through stupor and confusion on the way to recovering
clear consciousness
e. Coma may occur
f. Presence of the APOE-E4 allele is a risk factor for increased problems after a
brain injury
g. Phineas Gage
A. Treatments and Outcomes
1. Prompt medical care is required
2. The majority suffering mild concussion improve quickly
3. 24% of TBI cases develop post-traumatic epilepsy, presumably because of the
growth of scar tissue in the brain
4. In a minority of cases, dramatic personality change occurs
5. Children with severe traumatic brain injury are more likely to be adversely
affected the younger they are
6. Severe injury cases have a poor prognosis
7. Recent evidence suggests that patients with TBI may benefit from treatment
with donepezil, and acetylcholinesterase inhibitor
VI. Unresolved Issues: Can Dietary Supplements Enhance Brain Functioning?
A. Gingko biloba (derived from the leaves of the gingko tree) widely used to
improve memory
1. Oken and colleagues (1998) found that AD patients who received gingko
performed better cognitively than patients who took placebo; results similar to
when patients took donepezil
2. More recent study (2000) failed to find any effects
3. Gold and colleagues (2002) support Oken’s study
B. Other cognitive enhancers?
1. Phosphatatidylserine (PS) has been recommended for memory but findings
are inconsistent and minimal
2. Results looking at choline, found in foods containing lethicin, seem to be
equally Insignificant
Key Terms
AIDS-related dementia
amnestic syndrome
amyloid plaques
anterograde amnesia
APOE-4 allele
delirium
dementia
early-onset Alzheimer’s disease
functional mental disorders
late-onset Alzheimer’s disease
neurofibrillary tangles
organic mental disorders
retrograde amnesia
traumatic brain injury (TBI)
vascular dementia (VAD)