NEUROPSYCHOLOGY PERSPECTIVES AND HISTORY:STRUCTURE AND FUNCTION

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Clinical Psychology (PSY401)

Lecture 41

NEUROPSYCHOLOGY PERSPECTIVES AND HISTORY

A very important growth area in clinical psychology over the past several decades has been the field of

neuropsychology. This growth has been reflected in

(1) increases in membership in professional neuropsychological associations;

(2) The number of training programs that offer neuropsychology courses; and (3) the many papers, books,

and journals now being published on neuropsychological topics.

As the field moves into its "early adulthood," the primary challenge appears to be health care reform

(Meier, 1997). The number of jobs available to clinical neuropsychologist is no longer unlimited, and the

clinical services offered by neuropsychologists will need to be provided at lower cost and higher

effectiveness (Meier, 1997). Let us begin, however, by taking a step back in order to get a better sense of

how this field developed as well as the roles of neuropsychologists.

As the term would suggest, neuropsychologists have a foot in both the psychological and neurological

domains. While some have received their basic training in clinical psychology, others have been trained by

neurologists.

DEFINITION:

What is neuropsychology? Most simply, it can be defined as the study of the relation between brain

function and behavior.

"It deals with the understanding assessment, and treatment of behaviors directly related to the functioning of

the brain" (Golden, 1984).

Neuropsychological assessment is a non-invasive method of describing brain functioning based on a

patient's performance on standardized tests that have been shown to be accurate and sensitive indicators of

brain-behavior relationships.

The neuropsychologist may address issues of cerebral [brain] lesion lateralizations, localization, and

cerebral lesion progress. Neuropsychological evaluations have also provided useful information about the

impact of a patient's limitations on educational, social, or vocational adjustment. Since many patients with

neurological disorders, such as degenerative diseases. cerebrovascular accident, or multiple sclerosis, vary

widely in the rate at which the illness progresses or improves, the most meaningful way to assess patients

for the seventy of their condition is to assess their behavior objectively via neuropsychological assessment

procedures.

ROLE OF NEUROPSYCHOLOGISTS

Neuropsychologists function in a number of different roles (Golden et al.. 1992). First, neuropsychologists

are often called on by neurologists or other physicians to help establish or rule out particular diagnoses. For

example, a patient may present with a number of symptoms that may have either a neurological or an

emotional basis. Neuropsychological test results may help clarify the diagnosis in this situation. Second,

because of an emphasis on functional systems of the brain neuropsychologists can often make predictions

regarding the prognosis for recovery. A third major role involves intervention and rehabilitation.

Information provided by neuropsychologists often has important implications for treatment; test results

provide guidance as to which domains of functioning may support rehabilitative efforts. Finally,

neuropsychologists may be asked to evaluate patients with mental disorders in order to help predict the

course of illness (based on, for example, the degree of cognitive impairment present) as well as to help tai-

lor treatment strategies to patients' strengths and weaknesses (Keefe, 1995).

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With these definitions and descriptions of the roles of neuropsychologists in mind, we now turn to a brief

history of the field.

HISTORY OF NEUROPSYCHOLOGY

Theories of Brain Functioning. As in most areas of psychology, the historical roots of neuropsychology

extend about as far back in time as we are inclined to look. Some authors point to the Edwin Smith Surgical

Papyrus, a document thought to date between 1.700 and 3000 B.C., which discusses localization of function

in the brain (Walsh & Darby, 1999). Others suggest that it all began when Pythagoras said that human

reasoning occurs in the brain. Others are partial to the second century A.D. when Galen, the Roman

physician argued that the mind was located in the brain, not in the heart as Aristotle had claimed.

However, the most significant early base for neuropsychology seems to have been laid in the nineteenth

century (Hartlage, 1987). Researchers then were beginning to understand that damage to specific cortical

areas was related to impaired function of certain adaptive behaviors. The earliest signs of this understanding

came with Franz Gall and his now discredited phrenology. Gall believed that certain individual differences

in intelligence and personality (such as reading skills) could be measured by noting the bumps and

indentations of the skull. Thus, the size of a given area of the brain determines the person's corresponding

psychological capacity. This was the first popularization of the notion of localization of function.

Localization achieved much greater credibility with Paul Broca's surgical work in 1861. Observations from

two autopsies of patients who had lost their powers of expressive speech convinced Broca that he had found

the location of motor speech. Within the next 30 to 40 years, many books presented maps of the brain that

located each major function (Golden, 1984).

Others, such as Pierre Flourens, would surgically destroy certain areas of the brains of animals and then

note any consequent behavioral losses. Such work led Flourens and later, in the early twentieth century,

Karl Lashley to argue for the concept of equipotentiality. That is, although there certainly is localization of

brain function, the cortex really functions as a whole rather than as isolated units. In particular, higher

intellectual functioning is mediated by the brain as a whole, and any brain injury will impair these higher

functions. Yet there is the ability of one area of the cortex to substitute for the damaged area.

Both the localization and equipotentiality theories presented some problems, however. Localizationalists

could not explain why lesions in very different parts of the brain produced the same deficit or impairment,

whereas those adhering to the equipotentiality theory could not account for the observation that some

patients with very small lesions manifested marked, specific behavioral deficits (Golden et al., 1992).

An alternative theory that integrates these two perspectives is the functional model. First proposed by the

neurologist Jackson and later adapted by the Soviet neuropsychologist Luria, the functional model holds

that areas of the brain interact with each other to produce behavior. Behavior "is conceived of as being the

result of several functions or systems of the brain areas, rather than the result of unitary or discrete brain

areas. A disruption at any stage is sufficient to immobilize a given functional system" (Golden et al., 1992).

The importance of this formulation is that it can account for many of the clinical findings that are

inconsistent with previous theories.

According to the functional model, the nature of the behavioral deficit will depend on which functional

system (such as arousal, perception, or planning behavior) has been affected, as well as the localization of

the damage within that functional system. Finally, through a process called reorganization, recovery from

brain damage is sometimes possible.

NEUROPSYCHOLOGICAL ASSESSMENT:

With regard to specific psychological assessment instruments, neurology was for a long time bewitched by

notions of mass action of brain functioning. These ideas tended to make localization of function a secondary

goal of diagnosis, and brain damage was often viewed as a unitary phenomenon. The psychological tests

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used (for example, the Benton Visual Retention Test and the Graham-Kendall Memory-for-Designs Test)

were oriented toward the simple assessment of the presence or absence of brain damage. Information about

specific test correlates of specific brain lesions was not collected very efficiently.

Neuropsychology as a field began to grow immediately after World War II, because of (1) the large

numbers of head injuries in the War and (2) the development of the field of clinical psychology itself

(Hartlage, 19871). An important development of the postwar period was the work of Ward Halstead. By

observing people with brain damage in natural settings, Halstead was able to identify certain specific

characteristics of their behavior. Next, he tried to assess these characteristics by administering a variety of

psychological tests to these patients.

Through factor analysis, he settled on ten measures that ultimately comprised his test battery. Later, Ralph

Reitan, a graduate student of Haistead's, refined the battery by eliminating two tests and adding several

others. Subsequently, Reitan and his colleagues could relate test responses to such discrete aspects of brain

lesions as lateralized motor deficits. This work culminated in the Halstead Reitan Neuropsychological Test

Battery. By 1980 the Luria-Nebraska Neuropsychological Battery had been developed, and it is now

frequently used as an alternative to the Halstead-Reitan Battery. We'll have more to say about these and

other neuropsychological tests in a later section.

An additional historical development deserves mention here. Contemporary clinical neuropsychologists

have increasingly adopted a flexible battery approach to assessment; Flexible batteries allow each

assessment to be tailored to the individual, based on the clinical presentation and on the hypotheses of the

neuropsychologist. Standard batteries, such as the Halstead-Reitan and the Luria-Nebraska, may be too time

consuming and are not easily modified to accommodate specific clinical situations.

THE BRAIN: STRUCTURE, FUNCTION, AND IMPAIRMENT

Before proceeding, it will be helpful to review) the important aspects of the brain. This will, of necessity, be

a brief excursion.

STRUCTURE AND FUNCTION

The brain consists of two hemispheres. The left hemisphere controls the right side of the body and is

thought to be more involved in language functions, logical inference, and detail analysis in almost all right-

handed individuals and a good many left-handers as well. The right hemisphere controls the left side of the

body. It is more involved in visual-spatial skills, creativity, musical activities, and perception of direction.

But, again, note that some left-handers may reverse this hemispheric pattern. The two hemispheres

communicate with one another via the corpus callosum, which helps to coordinate and integrate our

complex behavior.

Each cerebral hemisphere has four lobes: the frontal, temporal, parietal, and occipital lobes. The frontal

lobes are the most recently developed parts of the brain in terms of evolution. They enable us to observe and

compare our behavior and the reactions of others to it in order to obtain the feedback necessary to alter our

behavior to achieve valued goals. Also associated with the frontal lobes are executive functions-formulat-

ing, planning, and carrying out goal-directed initiatives. Finally, emotional modulation the ability to

monitor and control one's emotional state-is also associated with frontal lobe functioning.

The temporal lobes mediate linguistic expression, reception, and analysis. They are also involved in

auditory processing of tones, sounds, rhythms, and meanings that are non language in nature. The parietal

lobes are related to tactile and kinesthetic perception, understanding, spatial perception, and some language

understanding and processing. They are also involved in body awareness. The occipital lobes are mainly

oriented toward visual processing and some aspects of visually mediated memory. Motor coordination, as

well as the control of equilibrium and muscle tone, is associated with the cerebellum.

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ANTECEDENTS OR CAUSES OF BRAIN DAMAGE

What causes brain damage? There are a number of possibilities.

1. Trauma:

It is estimated that head injuries occur in more than 2 million Americans every year Incidents producing

these injuries range from auto -mobile accidents to falls off a stepladder. The outcomes are wide-ranging,

and the nature of the head injury (such as closed versus open/penetrating) may have implications as well. Al

though most head injuries are considered mild, substantial percentage of cases requires hospitalization.

Head trauma is the leading cause of death and disability in young Americans (R. J Smith et al.. 1997).

The major effects of head trauma can be categorized as concussions, contusions, and lacerations.

Concussions (jarring of the brain) usually result in momentary disruptions of brain function although

permanent damage is uncommon (unless there are repeated concussions, as might b the case in football,

soccer, or boxing, for example). Contusions refer to cases in which the brain has been shifted from its

normal position and pressed against the skull. As a result, brain tissue is bruised. Outcomes can often be

severe and may be followed by comas and deliriums. Lacers tons involve actual ruptures and destruction of

brain tissue. They can be caused by bullets or flying objects, for example. These lacerations are of course,

exceedingly serious forms of damage.

2. Cerebro-vascular Accidents:

The blockage and rupture of cerebral blood vessels is often termed "stroke." This is a very common cause

of brain damage in adults, and stroke is one of the leading causes of death in the United States (and other

countries). Although primarily occurring in the elderly, stroke is also one of the most common causes of

death in middle-aged adults (Mora & Bornstein, 1997). In occlusions 3 blood clot blocks the vessel that

feeds a particular area of the brain.

This can result in aphasia (language impairment), apraxia (inability to perform certain voluntary

movements), or agnosia (disturbed sensory perception). In the case of a cerebral hemorrhage, the blood

vessel ruptures and the blood escapes onto brain tissue and either damages or destroys it. The exact

symptoms that ensue depend on the site of the accident and its severity. In very severe cases, death is the

outcome. Those who survive often show paralysis, speech problems, memory and judgment difficulties,

and so on.

It is very important to get stroke patients to the hospital immediately. Medications that essentially dissolve

occlusions ("clot-busting" medications) can limit the permanent damage from occlusive strokes. In addition,

new medications are being developed that prevent the cascade of chemical reactions responsible for neu-

ronal damage or even death (for example, tissue plasminogen activator, Therefore, in many cases, prompt

action can be of major benefit.

3. Tumors:

Brain tumors may grow outside the brain, within the brain, or result from metastatic cells spread by body

fluids from some other organ of the body, such as the lung or the breast. Initial signs of brain tumors are

often quite subtle and can include headaches, vision problems, gradually developing problems in judgment,

and so on. As the tumor grows, so does the variety of other symptoms (such as poor memory, affect

problems, or motor coordination).

Tumors can be removed surgically, but the surgery itself can result in more brain damage. Some tumors are

inoperable or located in areas too dangerous to operate on. In such cases, radiation treatments are often

used.

4. Degenerative Diseases:

This group of disorders is characterized by a degeneration of neurons in the central nervous system.

Common degenerative diseases include Huntington's chorea, Parkinson's disease, and Alzheimer's disease

and other dementia. Alzheimer's disease is the most common degenerative disease (age of onset is typically

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65 years old or older), followed by Parkinson's disease (age of onset 50 to 60 years old), and finally

Huntington's chorea (age of onset 30 to 50 years old).

In all three cases, there is progressive cerebral degeneration along with other symptoms in the motor areas.

Eventually, patients in these categories show severe disturbances in many behavioral areas, including mo-

tor, speech, language, memory, and judgment difficulties.

5. Nutritional Deficiencies:

Malnutrition can ultimately produce neurological and psychological disorders. They are most often

observed in cases of Korsakoff's psychosis (resulting from nutritional problems brought about by poor

eating habits common in longtime alcoholics), pellagra (niacin/vitamin B-3 deficiency), and beriberi

(thiamin/vitamin B-1 deficiency)

6. Toxic Disorders:

A variety of metals, toxins, gases, and even plants can be absorbed through the skin. In some instances, the

result is a toxic or poisonous effect that produces brain damage. A very common symptom associated with

these disorders is delirium (disruption of consciousness).

7. Chronic Alcohol Abuse:

Chronic exposure to alcohol often results in tolerance for and dependence on the substance. Tolerance and

dependence appear to have neurological correlates, including, for example, changes in neurotransmitter

sensitivity and shrinkage in brain tissue.

Several regions of the brain seem especially vulnerable to damage from chronic exposure to alcohol (U.S.

Department of Health and Human Services, 1997). We will highlight only a few of the most consistent

findings here. The limbic system is a network of structures within the brain associated with memory

formation, emotional regulation, and sensory integration. Studies of alcoholics have indicated deficits in

these areas of functioning. The diencephalon is a region near the center of the brain that includes the

mammillary bodies of the hypothalamus.

Studies suggest shrinkage or lesions in these areas as a result of chronic alcohol exposure, and memory

deficits in alcoholics are consistent with these findings. Several studies have also reported findings that

suggest alcoholics evidence atrophy of the cerebral cortex. Finally, damage to the cerebellum, responsible

for motor coordination, is also well documented. A history of accidental falls or automobile accidents may

suggest neurological damage resulting from alcohol abuse/dependence.

CONSEQUENCES AND SYMPTOMS OF BRAIN DAMAGE

Brain injury or trauma can produce a variety of cognitive and behavioral symptoms. Unfortunately for the

diagnostician, many of these symptoms may also occur in connection with traditional mental disorders.

Moreover, patients' responses to neurological impairment may give rise to psychological and emotional

reactions. For example, an individual with neurological damage may become depressed over the inability to

manage certain daily tasks. This, in turn, can easily obscure the process of differential diagnosis.

These difficulties aside, several common symptoms associated with neurological damage are listed below.

However, each of these may occur in every disorder, and there is considerable variation among patients

with the same disorder

1. Impaired orientation: inability, for example, to say who one is, name the day of the week, or know about

one's surroundings.

2. Impaired memory: patient forgets events especially recent ones, sometimes confabulates or invents

memories to fill the gaps, and may show impaired ability to learn and retain new information.

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3. Impaired intellectual functions: comprehension, speech production, calculation, and general knowledge

may be affected (for example, cannot define simple words, name the U.S. president, or add figures).

4. Impaired judgment: patient has trouble with decisions (for example, cannot decide about lunch, when to

go to bed, and so on).

5. Shallow and labile affect: person laughs or weeps too easily and often inappropriately; shifts from joy to

tears to anger, for example, very rapidly.

6. Loss of emotional and mental resilience: patient may function reasonably well under normal

circumstances, but stress (for example, fatigue, mental demands: motional upset) may result in deterioration

of judgment, emotional reactions, and similar problems.

BRAIN-BEHAVIOR RELATIONSHIPS

In the second half of the nineteenth century, localization of function became a popular view. The idea that

specific areas of the brain control specific behaviors is still an important operating principle among neuro-

psychologists. Such a principle means that in assessing brain damage, a chief concern is where the injury is

located in the brain. Extent of an injury is important only to the degree that larger injuries tend to involve

more areas of the brain indeed; some tumors may produce intracranial pressure that impairs areas located

far from the tumor itself. The basic idea; however is that same-sized lesions in different regions of the brain

will produce different behavior deficits.

But according to equipotential theory, all areas of the brain contribute equally to overall intellectual

functioning (Krech, 1962). Location of injury is secondary to the amount of brain injury. Thus, all injuries

are alike except in degree. Equipotentialists tend to emphasize deficits in abstract, symbolic abilities, which

are thought to accompany all forms of brain damage and to produce rigid, concrete attitudes toward

problem solving .Such views have led to the development of tests that attempt to identify the basic deficit

common to all cases of brain damage. Unfortunately, such tests have not worked well enough for everyday

clinical use (Golden, 1981).

Many investigators have been unable to accept either localization or equipotentiality completely. Thus,

alternatives such as the one proposed by Hughlings Jackson (Luria, 1973) have become prominent.

Although, according to Jackson, very basic skills can be localized, the observable behavior is really a

complex amalgamation of numerous basic skills, so the brain as an integrated whole is involved. This func-

tional model of the brain subsumes both localization and equipotential theory. Further, according to Luria

(1973), very complex behaviors involve complex functional systems in the brain that override any simple

area locations. Because our ability to abstract is a complex intellectual skill, for example, it involves many

systems of the brain.

Brain damage can have many effects, involving visual perception, auditory perception, kinesthetic

perception, voluntary motor coordination and functioning, memory, language, conceptual behavior,

attention, or emotional reactions. Often clinicians are called upon to determine the presence of intellectual

deteriotation.this goes beyond the measurement of present functioning because it involves an implicit and

explicit comparison to a prior level. generally speaking ,intellectual deterioration may be of two broad

types:

(1)a decline resulting from psychological factors(psychosis, lack of motivation, emotional problems, the

wish to defraud an insurance company, and so on);and

(2)a decline stemming from brain injury. Of course, assessment would be a good deal easier if the clinician

had available a series of tests taken by the patient prior to injury or illness. Such premorbid data would

provide a kind of baseline against which to compare present performance.unfortunately, clinical

psychologist seldom seem to have such data on the patients they most need to diagnose. They are left to

infer patient's previous level of functioning from case history information on education, occupation, and

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other variables. Over the years, clinicians have used such signs of premorbid functioning in a rather

intuitive fashion, without much empirical evidence for their validity.

INTERVENTION AND REHABILITATION

Issues of neurological impairment usually revolve around two principal questions. First, what is the nature

of the deterioration or damage? For example, is it a perceptual loss or a cognitive loss? Second, is there any

real brain damage that can account in some way for the patient's behavior? More specifically, is the damage

permanent, or can recovery be expected after an acute phase? Is the damage focal or diffused throughout the

brain? In general, focal damage results in more specific, limited effects on behavior, whereas diffuse

damage can cause wide effects.

Referral sources often need to know whether the damage will be progressive gas in diffuse brain

involvement or in damage caused by disease or nonprogressive (as is often true in the case of strokes or

head traumas). Answers provided by clinical neuropsychologists significantly affect the kinds of

rehabilitation programs designed for various patients.

Rehabilitation is becoming one of the major functions of neuropsychologists (Golden et al., 1992). The

neuropsychologist is often thrust into the role of coordinating the cognitive and behavioral treatment of

patients who have shown cognitive and behavioral impairment as a result of brain dysfunction or injury.

First, a thorough assessment of the patient's strengths and deficits is conducted; this may include not only

neuropsychological test results but also observations from other staff members, such as nurses. Physicians

and physical therapists. A program of rehabilitation is then developed that will be maximally beneficial to

the patient, given her or his deficits, as well as one that will be efficient in the sense of requiring a minimum

amount of staff time and supervision (Golden et al., 1992).

Rehabilitation can take place through spontaneous recovery of functioning. However, the neuropsychologist

and the rehabilitation team are more likely to be involved when rehabilitation is to be accomplished by

having the patient "relearn" via developmentally older and intact functional systems. The development of

new functional systems. Or changing the environment to ensure the best quality of life possible. In this last

case, the judgment may be that it will not be possible to develop alternative or new functional systems that

will significantly lessen the level of cognitive or behavioral impairment.

In the case of developing alternative or new functional systems, rehabilitation tasks are formulated to "treat"

the patient's deficits. Golden et al. (1992, pp. 214-215) offer the following general guidelines for

formulating this type of rehabilitation task:

1. It should include the impaired skill that one is trying to reformulate. All other skill requirements in the

task should be in areas with which the subject has little or no trouble.

2. The therapist should be able to vary the task in difficulty from a level that would be simple for the patient

to a level representing normal performance.

3. The task should be quantifiable, so that progress can be objectively stated.

4. The task should provide immediate feedback to the patient.

5. The number of errors made by the patient should be controlled.

Golden et al. (1992) give examples of rehabilitation programs for various cognitive and behavioral deficits.

For example, verbal memory impairment might be treated by administering simple memory problems

(those involving one unit of information) to the patient and then. Later, more complex tasks (for example, a

problem enquiring the memorization of six or seven units of information). The complexity of the task can

be varied further by, for example. Using unrelated words or decreasing the time of exposure to the stimulus

words.

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