Neuropsychological Assessment
by Gregory P. Lee, PhD
Definition
Neuropsychology is the study of brain-behavior relationships.
Clinical neuropsychology combines the knowledge base developed through classical,
localizationalist neurology with the modern methods of American psychometric psychology.
The objectives of neuropsychological assessment in clinical
practice are to assess and diagnose disturbances of mentation and behavior and to relate these findings to their neurological
implications and to the issues of clinical treatment and prognosis.
Methods
A variety of behavioral measures ("tests") are administered in
a standardized, controlled fashion, and the results are used to infer an individual's underlying ability and current functioning
in a number of broad cognitive domains. The major cognitive domains typically assessed in a
neuropsychological examination include: attention, memory, intelligence, language, visuoperception, visual-spatial thinking,
psychosensory and motor abilities, "frontal lobe" or executive functions, academic achievement, and personality or
emotional functions.
Performance on tests of cognitive abilities are compared with
normative performance levels of the general population. Negative deviation from these normal population levels may
suggest impairment, either constitutional or acquired, in a given cognitive domain. Cognitive strengths resulting from
training as well as natural ability are reflected by performances that exceed those of the general population.
Insult to various regions of the brain due to either injury or
disease may result in characteristic patterns of deficit. These patterns may be used to develop hypotheses about the
neurological processes involved as well as to generate descriptions of cognitive, emotional, and functional
competence.
Uses of Clinical Neuropsychological
Assessment
Diagnostic Clarification
In confusing or complex cases,
neuropsychological assessment can be useful for teasing out the relative contributions of neurological conditions (e.g.,
cellular degeneration, neurochemical disruption), emotional states (e.g., anxiety, depression), and psychiatric illnesses
(e.g., personality disorder, psychoses). Although neuropsychological assessment can be used to help localize
brain damage, high quality neuroimaging techniques have diminished its clinical utility in this area.
Measuring Change
Repeat assessment can be valuable in
charting progress (e.g., recovery from cerebrovascular accident or closed head injury) as well as for recognizing a
decline in mental status (e.g., following the course of various dementias, identifying unexpected declines in patients
undergoing various treatments or during the process of recovery).
Evaluating Cognitive and Functional Status
Neuropsychological testing is able to delineate an individual's
pattern of cognitive strengths and weaknesses relative to his or her own ability as well as compared to normative samples
of age-matched peers (Ideally, norms should be matched for age, education, gender, and race if each variable has been
shown to affect test performance). Inferences regarding functional ability can be drawn from neuropsychological data
or from actual tasks designed to evaluate the relevant behaviors.
Applications of Neuropsychological
Assessment
Vocational Interventions
With the input of the
neuropsychologist, a patient's ability to rejoin the work force can be evaluated and efforts toward re-entry can be
facilitated (e.g., develop specific routines that are tailored to the patient's existing strengths and that anticipate the impact
of his or her limitations). Aspects of neuropsychological testing can be integrated with organizational psychology in
order to enhance the quality of vocational assessment.
Academic Interventions
As with vocational interventions,
results of a neuropsychological assessment may be used to plan a special educational program to better meet the needs
of an individual. This may be useful with developmental disorders as well as with patients recovering from illness or
injury.
Family Interventions
Accurate knowledge about a patient's functional status may assist him or her to adjust their
role within a family system. Neuropsychological information may enable family members to recognize the need for
changes and accommodations within their relationships, highlight the need for environmental changes to accommodate
patient deficits, and provide an opportunity for emotional processing and eventual acceptance of the patient's
limitations.
Competency Issues
Neuropsychological status plays an
important role in determining a patient's overall competency. Questions typically involve one's ability to exercise rational
judgment, make competent decisions, and live in an independent fashion. In addition to cognitive status,
assessment of the patient's awareness of their limitations is also important in establishing ability for independent
functioning.
Methods of Neuropsychological Assessment
Medical History
All relevant medical records, especially
results of neurological examination, imaging studies, and electrophysiological (EEG) results.
Clinical Interview
Includes review of cognitive, sensorimotor, and neurovegetative complaints as well as
medical, psychiatric, and substance abuse history. Family members may be interviewed when necessary.
Behavioral Observations
Qualitative assessment of
mentation, motor function, speech, motivation for optimal test performance, emotion, manner of relating, and humor.
Psychometric Tests
These may be "paper and pencil"
tasks or measures requiring performance of a relevant skill (e.g., assembly of blocks or puzzles, reaction time tasks).
Major cognitive domains typically assessed include: Attention, Memory, Intelligence,
Visual-Spatial-Perceptual functions, Psychosensory and Motor abilities, "Executive" or
"Frontal Lobe" functions, and Personality or Emotional Functioning.
Interpretation of Results
Deficit patterns occurring across neuropsychological tests can be suggestive of various sites of
cerebral dysfunction and neurological processes underlying the deficit pattern. An effort is made by the neuropsychologist
to integrate test data, history, clinical interview, behavioral observations, and available laboratory and radiological
evidence into one cohesive summary report that arrives at a neurobehavioral diagnosis, discusses the neurological
implications (e.g, localization, course, prognosis), and can be used in the process of treatment planning.
Clinical Purposes of Neuropsychological Assessment
1. Aid in the detection of neurological disorders.
2. Determine if a developmental learning disorder or other
neurodevelopmental disorder exists and specify subtype, prognosis, and treatment strategies.
3. Assess adaptive functioning in response to neuropathology
or psychopathology and use this information to assist in educational and vocational planning.
4. Provide information about the course and prognosis of
deficits.
5. Evaluate improvement or deterioration in
cognition to
determine treatment efficacy (e.g., drug effects) or to track decline in progressive diseases.
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© 1998, Medical College of Georgia.
About the author - Gregory
Price Lee, PhD, is a Professor and Director of Neuropsychology Service, Departments of Surgery
(Neurosurgery) and Psychiatry, Medical College of Georgia.
This article is posted on NLD on the Web! with the permission of the
author.
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