Download CHAPTER 14: Neurocognitive Disorders

CHAPTER 14: Neurocognitive Disorders
Chapter Overview/Summary
The DSM-5 recognizes various neurocognitive disorders. The DSM-IV-TR disorders of delirium, dementia, and
amnestic disorder are now classified as either major neurocognitive disorder or mild neurocognitive 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, whereas 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 genetic APOE-4
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 a deteriorating course.
The most common cause of dementia is Alzheimer’s disease (AD). 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 APOE-4 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 from 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 Outline
I.
II.
Brain Impairment in Adults
A.
Diagnostic Issues
1.
Disorders known as “Delirium, Dementia, and Amnestic and Other Cognitive Disorders”
in DSM-IV-TR are now grouped as “Neurocognitive Disorders” in DSM-5.
2.
These disorders involve a loss of cognitive ability due to brain damage or disease.
3.
There are two broad subcategories based on severity: major neurocognitive disorder
(formerly dementia) and mild neurocognitive disorder.
B.
Thinking Critically about DSM-5: Is the Inclusion of Mild Neurocognitive Disorder a Good
Idea?
C.
Clinical Signs of Brain Damage
1.
For most part, cell bodies and neural pathways do not regenerate; when occurs in older
children or adults there is a loss in established functioning.
2.
Impairment may involve acquired and customary skills or the capacity for realistic selfappraisal (anosognosia).
D.
Diffuse versus Focal Damage—see Table 14.1 for Impairments Associated with Brain Disorders
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.
Diffuse or widespread damage may occur with loss of oxygen to the brain or ingestion of
toxin-like mercury.
3.
Mild cognitive impairment can also be detected in those who have had only low-level
exposure to organic solvents and other neurotoxins.
4.
Focal brain lesions are circumscribed areas of abnormal change in the brain with a
number of possible consequences.
5.
Relationships between brain location and behavior can never be considered universally
true, however (see Figure 14.2 for anatomy of the brain).
a.
Damage to frontal areas can result in one of two patterns:
(1)
Being unmotivated and passive, limited thoughts and ideas.
(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 (see Figure 14.2).
E.
The Neuropsychology/Psychopathology Interaction
1.
Most people with a neuropsychological disorder do not have psychopathological
symptoms, such as panic attacks, dissociative episodes, or delusions.
2.
People with favorable life situations do better after brain injury than those who are
disadvantaged.
3.
Mild deficits in cognitive self- processing and regulation.
4.
Psychopathological symptoms are not always predictable.
5.
Never assume a psychological disorder is developed because of brain damage.
6.
Involves impairment of memory and attention as well as disorganized thinking.
Delirium
A.
Clinical Picture
1.
Delirium is an acute confused state with a sudden onset and a fluctuating state of
awareness.
2.
Nuances consistent with patient’s age, personality, and complete psychological situation
confronting the patient.
3.
4.
B.
III.
Sudden onset.
Commonly find: cognitive changes such as impaired information-processing,
hallucinations, delusions, abnormal psychomotor activity (wild thrashing), disturbances
of the sleep cycle, confusion, disturbed concentration, and cognitive dysfunction.
5.
See Figure 14.3.
6.
Latin delirare meaning out of one’s furrow or track.
7.
Can occur at any age, but elderly are at a greater risk; 10%–51% of patients who undergo
surgery, particularly cardiac surgery, develop delirium; 25% of elderly with delirium die
within 6 months.
8.
May result from head injury, infection, drug intoxication, drug withdrawal, drug toxicity.
Treatments and Outcomes
1.
Medical emergency—must identify and treat underlying cause.
2.
Most cases are reversible except when caused by terminal illness and severe brain trauma
3.
Treatment involves medications (neuroleptics or benzodiazepines for drug withdrawal),
environmental manipulations such as orienting techniques (calendars, staff prompting,
night lights), and family support.
Major Neurocognitive Disorder (Dementia)
A.
Dementia Renamed
1.
Renamed to reduce stigma and to make appropriate for younger adults with cognitive
problems.
2.
Decline from a previous level of functioning; onset is typically gradual.
3.
Early on individuals may appear alert and fairly well tuned to the events going on in the
environment.
4.
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.
5.
Often accompanied by impairment in emotional control and moral/ethical sensibilities
6.
Dementia may be progressive or static.
7.
Occasionally reversible if underlying cause can be treated, such as vitamin deficiency.
8.
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.
9.
See Figure 14.4 for causes of dementia (major neurocognitive disorder).
B.
Parkinson’s Disease
1.
Second most common neurodegenerative disease (after Alzheimer’s). More than 75%
will show signs of dementia eventually. Named after James Parkinson, first described in
1817.
2.
Affects between .05%–1% of people aged 65–69 and 1%–3% over 80. That said, some
develop it far earlier (e.g., Michael J Fox was diagnosed when he was 30, reveals his
story in his book, “Lucky Man” (2002)).
3.
Caused by loss of dopamine, causes tremors and rigid movements.
4.
More common in men than women, 25%–40% show signs of dementia.
5.
Mirapex prescribed as a way to increase dopamine.
6.
Dopamine is key in the control of movement.
7.
Can involve psychological symptoms like depression, anxiety, apathy, cognitive
problems, hallucinations, and delusions.
8.
Genetic and environmental factors indicated in the onset.
9.
Smoking and drinking coffee may provide some protection against the development.
C.
Huntington’s Disease
1.
A rare degenerative disorder affecting 1:10,000, with an average age of onset of mid40’s. Discovered in 1872 by Dr. George Huntington.
2.
Characterized by chronic involuntary and irregular movements.
3.
Patients develop dementia and many die within 10 years.
4.
D.
Caused by problem on chromosome 4 and highly heritable. If a parent has the disease,
offspring have a 50% chance of developing the disease.
5.
Affects men and women equally.
6.
A genetic test is available for those who qualify but only 10% choose to take the test
7.
Cognitive problems due to the loss of brain tissues are common.
8.
Patients usually develop dementia, and death occurs 10–20 years after the age of onset.
Alzheimer’s Disease (AD)
1.
Clinical picture
a.
In DSM-5 called “major (or mild) neurocognitive disorder associated with
Alzheimer’s disease.”
b.
Diagnosis based on clinical assessment but can be confirmed only after death.
c.
Usually begins after age 45.
d.
A progressive and fatal degenerative disorder named for Alois Alzheimer
(1864–1915), was first described in 1907.
e.
Gradual and slow mental deterioration with multiple cognitive deficits.
f.
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 the 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.
g.
Delusions (paranoid and jealous) and a combative pattern occur in some
patients.
h.
Death usually comes from lowered resistance to opportunistic infections.
i.
See Figure 14.5.
2.
Prevalence
a.
Problem is underestimated.
b.
AD rates double approximately every 5 years after a person reaches age 40.
c.
Less than 1% of the population between ages 60–64 is affected; about 40% of
those over 85 are affected.
d.
Worldwide: 35 million people are living with AD.
e.
By 2030 it is estimated that 66 million will be living with AD.
f.
With increasing lifespan, problem grows in magnitude.
g.
Women have a slightly higher risk.
h.
Lower rates in Africa, Southeast Asia, and India, suggesting role of high fat,
high-cholesterol diet.
i.
High levels of an amino acid homocystine increase the risk for AD and heart
disease.
3.
Causal factors
a.
Early-onset Alzheimer’s disease
(1)
Progression is very rapid.
(2)
See Table 14.3.
(3)
Have identified three rare genetic mutations that can cause Alzheimer’s
(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)
(4)
4.
5.
6.
7.
E.
F.
Genetic susceptibility thought to interact with environmental factors.
Environmental factors include diet, exposure to metals such as
aluminum, and experiencing head trauma.
(5)
Use of ibuprofen may be protective.
(6)
14.2 Developments In Research: Depression Increases the Risk of
Alzheimer’s Disease.
Neuropathology (see Figure 14.6 for a diagram of a brain with Alzheimer’s disease)
a.
Amyloid plaques
(1)
Contain a sticky substance called beta amyloid.
(2)
Believed that an accumulation of this substance causes plaques.
(3)
Beta amyloid is neurotoxic.
b.
Neurofibrillary tangles
(1)
Webs of abnormal filaments within a nerve cell made up of a protein
called tau.
(2)
Tau may be caused by accumulation of beta amyloid.
c.
Atrophy of the brain
(1)
Small holes caused by cell degeneration.
(2)
Leads to reduction in acetylcholine activity.
Treatment and outcome
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) inhibit the
production of acetylcholinesterase, thereby increasing the availability of
acetylcholine.
d.
Donepezil.
e.
Newest medication: Namenda, appears to regulate glutamate.
f.
Despite setbacks, continuing to work on developing vaccines.
g.
Prevention is needed.
Early detection
a.
Brain-imaging techniques.
b.
APOE-E3 allele.
c.
Experience of mild cognitive impairment (MCI).
d.
Atrophy of hippocampus.
e.
The World Around Us: Exercising Your Way to a Healthier Brain?
Supporting caregivers
a.
Challenging management problems as well as “social death” of the patient and
their own “anticipatory grief.”
b.
Sandra Day O’Connor’s story.
c.
Caregivers are at high risk for developing depression and cortisol levels similar
to people with depression.
d.
Providing caregivers with counseling and support has proven effective.
Neurocognitive Disorder Associated with 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 the 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 20% –30% percent of untreated patients with HIV/AIS will develop AIDSrelated dementia; with current antiviral treatment, the rate reduces to 20%.
Neurocognitive Disorder Associated with Vascular Disease (Vascular Dementia)
1.
A similar clinical picture to Alzheimer’s exists, although a more varied early picture.
2.
IV.
V.
Series of circumscribed cerebral infarcts cumulatively destroy neurons over expanding
brain regions.
3.
Tends to occur after age 50; more common in men.
4.
Accounts for only about 19% of all dementia cases age 65 or older; patients are more
vulnerable to sudden death from stroke or cardiovascular event.
5.
Accompanying mood disorders more common than in AD.
6.
“Mixed” diagnoses when patient has both vascular and AD.
7.
Cerebral arteriosclerosis can be medically managed to some extent.
Amnestic Disorder
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 of 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.
F.
Korsakoff’s syndrome—an amnestic disorder caused by vitamin B1 deficiencies.
G.
In DSM-5, amnestic disorder (in DSM-IV-TR) is classified as “major neurocognitive disorder.”
Disorders Involving Head Injury
A.
Traumatic Brain Injury (TBI)
1.
Occur frequently, affecting more than 2 million people each year in the United States.
2.
Children ages 0–4, adolescents 15–19, and adults over 65 most at risk.
3.
DSM-5 uses diagnostic term of “major (or mild) neurocognitive disorder associated with
head trauma” for cognitive problems that result from head injury.
4.
15% of soldiers who served in Iraq war.
5.
Most common cause is motor vehicle accidents followed by falls, violent assaults, and
sports injuries.
6.
Case of Arizona Congresswoman Gabrielle Giffords.
7.
Men aged 15–24 are at greatest risk.
B.
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.
Minor closed-head injuries as a result of car accidents, athletic injuries, falls,
and other mishaps. Roller coasters with high G-forces can even cause brain
injury.
g.
Presence of the APOE-E4 allele is a risk factor for increased problems after a
brain injury.
h.
Phineas Gage.
i.
See Figure 14.7.
j.
See Table 14.5.
C.
The World around Us: Brain Damage in Professional Athletes
D.
Treatments and Outcomes
1.
Prompt medical care is required.
2.
The majority suffering mild concussion improve quickly.
3.
VI.
24% of TBI cases develop post-traumatic epilepsy, presumably because of the growth of
scar tissue in the brain, seizures develop within two years of injury.
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 at the time of the injury, and the less language, fine-motor, and other
competencies.
6.
Severe injury cases have a poor prognosis.
7.
Recent evidence suggests that patients with TBI may benefit from treatment with
donepezil, an acetylcholinesterase inhibitor.
8.
Treatment is complex, long, and expensive.
9.
Includes many interventions such as medication, rehabilitation, interventions, social skills
training, vocational and recreational training, etc.
10.
See Table 14.6: Predictors of Clinical Outcome After Traumatic Brain Injury.
Unresolved Issues: Should Healthy People Use Cognitive Enhancers?
A.
Caffeine
1.
Improves vigilance, working memory, and incidental learning.
B.
Nicotine
1.
Enhances attention, working memory, and attention in short term.
C.
Prescription medication.
1.
Ritalin.
2.
Provigil.
Key Terms
Alzheimer’s disease
amnestic disorder
amyloid plaques
anterograde amnesia
APOE-4 allele
delirium
dementia
early-onset Alzheimer’s disease
HIV-associated neurocognitive impairment
Huntington’s disease
Korsakoff’s syndrome
late-onset Alzheimer’s disease
major neurocognitive disorder
mild neurocognitive disorder
neurofibrillary tangles
Parkinson’s disease
retrograde amnesia
traumatic brain injury (TBI)
vascular dementia