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Neuropsychology/Neuropsychologists

Neuropsychology is a branch of clinical psychology that studies how the brain and nervous system affect how we function on a daily basis. Unlike the use of neuroimaging techniques such as MRI, CT scans and EEG where the focus is on nervous system structures, neuropsychology seeks to understand how the various components of the brain are able to do their jobs. Clinical neuropsychology makes use of various assessment methods to ascertain function and dysfunction and applies this knowledge to evaluate, treat and rehabilitate individuals with suspected or demonstrated neurological or psychological problems.

According to the National Academy of Neuropsychology (www.nanonline.org) a clinical neuropsychologist is a professional within the field of psychology with special expertise in the applied science of brain-behavior relationships. Clinical neuropsychologists use this knowledge in the assessment, diagnosis, treatment, and/or rehabilitation of patients across the lifespan with neurological, medical, neurodevelopmental and psychiatric conditions, as well as other cognitive and learning disorders. The clinical neuropsychologist uses psychological, neurological, cognitive, behavioral, and physiological principles, techniques and tests to evaluate patients' neurocognitive, behavioral, and emotional strengths and weaknesses and their relationship to normal and abnormal central nervous system functioning. The clinical neuropsychologist integrates information gathered during the evaluation process with information provided by other medical/healthcare providers to identify and diagnose neurobehavioral disorders, and plan and implement intervention strategies. The specialty of clinical neuropsychology is recognized by the American Psychological Association and the Canadian Psychological Association. Clinical neuropsychologists are independent practitioners (healthcare providers) of clinical neuropsychology and psychology.

Neuropsychologists

Neuropsychologists are not medical doctors, but doctors of psychology whose field of study is concentrated on the brain and its functions. Neuropsychological testing is designed to determine the brain's capacity with respect to short and long term memory, abstract reasoning, attention, concentration, executive functioning, motor skills and other cognitive and psychological factors. By comparing the pattern of these results, against the patients pre-morbid capabilities, and correlating these results with the nature of the trauma suffered by the patient, neuropsychologists can, to a reasonable degree of certainty, opine that individuals without an acute diagnosis of brain injury, have permanent deficits as a result of brain trauma.

In many cases, medical doctors, insurance adjusters and defense attorneys will minimize the survivor's injuries because of negative scanning tests, such as X-Ray, MRI and CT scan. The favorite defense phrase is "no objective evidence of injury". But normal imaging studies do not rule out a brain injury. In such cases, neuropsychological assessment can be "objective evidence of injury". In fact, neuropsychological testing is the "gold standard" against which other diagnostic tools are measured to determine the existence of pathology to the brain. Only autopsy studies are more accurate.

Neuropsychologists use batteries of tests to triangulate the brain's functioning and through that triangulation, determine whether the brain is functioning as it should. Just like tapping a knee to check the reflexes is an objective test of how the nervous system operates, neuropsychological tests are an objective measure of how the brain is functioning. If a neuropsychologist is using what is called a "fixed battery" they will be using one of two such batteries, the Halstead-Reitan or the Luria-Nebraska battery. The advantage of using such batteries is that decades of study and thousands of test results have created an accurate profile of the pattern of deficits which correlate to specific types of brain injury.

The Halstead-Reitan Battery consists of the Category Test, Tactual Performance Test, Seashore Rhythm Tests, Speech Sounds Perception Tests, Finger Tapping Test, and Trail Making. Neuropsychologists often administer Full Scale IQ, Verbal IQ, and Performance IQ. The most commonly employed intelligence test is the Wechsler Adult Intelligence Scale-Revised (WAIS-R). The three summary IQ measures are derived from averaging individual subtest scores. An Aphasia Screening Test, a Sensory-Perceptual Examination, are also typically administered, and many neuropsychologists will also administer the MMPI as well.

A normal IQ score, or even high test scores in specific areas, do not rule out brain injury. First, if a person had a 130 IQ before the injury and a 100 IQ after, this would clearly establish injury. More significantly, many profoundly brain injured survivors, maintain an average IQ near their pre-morbid levels. It is not their average scores that are significant, but the pattern of such scores. This graph shows the typical test variability often seen in neuropsych testing, which correlates to a diagnosis of permanent brain injury. Plus, the IQ only measures certain brain functions, those primarily cognitive in nature. The neuropscyh exam is designed to evaluate a comprehensive cross section of brain function.

Neuropsychological evaluation (NPE)

Neuropsychological evaluation (NPE) is a testing method through which a neuropsychologist can acquire data about a subject’s cognitive, motor, behavioral, linguistic, and executive functioning. In the hands of a trained neuropsychologist, these data can provide information leading to the diagnosis of a cognitive deficit or to the confirmation of a diagnosis, as well as to the localization of organic abnormalities in the central nervous system (CNS). The data can also guide effective treatment methods for the rehabilitation of impaired patients.

NPE provides insight into the psychological functioning of an individual, a capacity for which modern imaging techniques have only limited ability. However, these tests must be interpreted by a trained, experienced neuropsychologist in order to be of any benefit to the patient. These tests are often coupled with information from clinical reports, physical examination, and increasingly, premorbid and postmorbid self and relative reports. Alone, each neuropsychological test has strengths and weaknesses in its validity, reliability, sensitivity, and specificity. However, through eclectic testing and new in situ testing, the utility of NPE is increasing dramatically.

Function categories

NPE is useful for measuring many function categories, including the following:

• Intellectual functioning
• Academic achievement
• Language processing
• Visuospatial processing
• Attention/concentration
• Verbal learning and memory
• Visual learning and memory
• Executive functions
• Speed of processing
• Sensory-perceptual functions
• Motor speed and strength
• Motivation/symptom validity
• Personality assessment

NPE is used to quantitatively measure the cognitive and behavioral capabilities of a patient. The data from neuropsychological tests can then be compared with normative data based on a number of different demographic criteria, including (but not limited to) age, race, gender, and socioeconomic status. NPE can include testing of intelligence, attention, memory, and personality, as well as of problem solving, language, perceptual, motor, academic, and learning abilities.

Neuropsychological testing provides diagnostic clarification and grading of clinical severity for patients with obvious or supposed cognitive deficits. Often these include patients with a history of any of the following problems:

• Head injury
• Failure to achieve developmental milestones
• Learning or attention deficits
• Exposure to drugs, alcohol, or maternal illness in utero
• Exposure to chemicals, toxins, or heavy metals
• Parkinson disease
• Seizure disorders
• Substance abuse
• Strokes
• Dementia
• Psychiatric disorders

NPE is of limited value if a patient is severely compromised, as in advanced dementia or early in recovery from serious brain injury (eg, TBI, stroke, anoxia, infection), although brief serial assessment with measures such as the Galveston Orientation and Amnesia Test, high-velocity lead therapy (HVLT), digit span, and motor speed and dexterity is very useful in tracking recovery. NPE's value is also limited if a patient has other serious medical complications or psychiatric disorders.

Neuropsychological Testing