|
|
 |  | |
Medical Articles »Randall Smith, Ph.D.
Psychological Testing in Assessing Chronic Pain
Randall Smith, Ph.D.
Psychology & Neuropsychology
Psychological tests are indispensable in the chronic pain workup. They are a source of both subjective and objective data of demonstrable validity and reliability. In clinical context, selected psychological tests are extremely helpful in identifying depression, somatization, hypochondriasis, and other conditions which can influence and determine complaints of back pain. The use of psychological tests in evaluating back pain is advocated by many well-established and generally accepted orthopedists. Southwick (1983) states that "the most illuminating studies are those that have included a battery of psychological tests."
The use of psychological tests in evaluating chronic back pain requires the selection of a battery of tests that is suited to the questions at issue, and is also cost-effective. A mix of self-administered and examiner-administered tests is most often useful. If secondary gain is a consideration, it is best to view the scores of self-report measures (e.g., Whaler Physical Symptoms Inventory, Beck Depression Inventory, etc.) as indicative of how the patient wishes to be seen by others. Optimal selection and interpretation of a psychological test battery demands that the testing psychologist take a history and perform a mental status examination so that the tests are interpreted in clinical context, rather than "blind." A typical test battery should include:
a) a general measure of cognitive functioning
b) self-report measures of physical and / or psychological functioning
c) a "personality" test such as the MMPI-2
d) a projective test
e) appropriate measures to assess motivational and self-report style
f) additional measures as clinically warranted
Psychological test data, appropriately utilized, can shed considerable light upon the nature of somatic complaints and allow description of several dimensions important in the evaluation of chronic back pain, including:
a) the intellectual capacities and vulnerabilities of the patient
b) the response set of the patient during the testing
c) the nature and magnitude of any psychiatric disorders evidenced by the patient
d) the relative balance of state vs trait variables in the patient's presentation
e) disability status factors, especially with regard to cognitive and interpersonal issues
f) clinical prognosis
g) ability to benefit from counseling, psychotherapy, or involvement in a chronic pain program
h) capacity to participate in back school, work hardening, or vocational rehabilitation activities
The MMPI-2
One of the most common and clinically useful test measures is the MMPI-2. The MMPI-2 enables a description of validity and response set issues, as well as the patient's placement on ten basic clinical scales. The validity indices are extremely useful in enabling the psychologist to describe the specific nature of the patient's response style. Additionally, the issue of possible conscious symptom misrepresentation can be directly addressed. Scales pertinent to these issues on the MMPI-2 include L, F, K, VRIN, TRIN, Fb, Fp, S, and the Lees-Haley Fake Bad Scale (Lees-Haley, et al, 1991) for personal injury and workers' compensation claimants. Psychologists should use the Lees-Haley scale with caution as there has been limited cross validation of the findings to date. Hundreds of supplemental clinical scales have been developed over the years and many are useful in the psychological scrutiny of a patient.
The presence of functional pain is heralded on the MMPI-2 by a rather strikingly consistent set of scale elevations. Most well-known is the "Conversion V" in which Scales 1 and 3 (hypochondriasis and hysteria) are elevated while Scale 2 (depression) is lower. The research basis for the MMPI-2 is broad and the trained psychologist can develop many useful clinical inferences from the test, not only regarding functional pain, but also about psychiatric disorders and the presence of clinically significant personality traits. MMPI-2 inferences are best understood contextually and should take into account the level and type of cognitive functioning, secondary gain potential, and other factors. Wiltse (1975), Southwick (1983) and others have indicated that the MMPI is helpful in identifying somatization as well as in predicting the outcome of surgical treatment. Wiltse found the MMPI capable of predicting a poor surgical outcome, regardless of associated physical or other findings. Sorensen (1992) found that a number of psychological test factors were predictive of good or poor outcomes among a sample of patients undergoing first lumbar spine surgeries. High scores on scales 1 and 3 of the MMPI-2 predicted poor outcome; the presence of a "Conversion V" was related to a poor subjective response to surgery.
Tollison and Satterthwaite (1990) found that the MMPI aided in determining which patients would be likely to report a subjectively positive outcome from lumbar spine surgery. Thorveldsen and Srensen (1990) found that psychological problems as indicated by the MMPI boded poorly for a positive subjective response to lumbar spine surgery regardless of objective surgical findings, pre-operative general health, age, and gender. Gallagher, et al (1989) found that when age and time out of work were controlled as variables, physiological status alone was not an adequate predictor of the likelihood that an individual would return to work after developing lumbar pain. They concluded that elevations on MMPI Scale 3, perceived health locus of control, and ability to function in the course of doing daily activities were all important predictive variables for return to work within six months. In an effort to examine the issue of whether elevated MMPI scores reflect, cause or effect in chronic pain evaluations, Leavitt and Katz (1989) found that identified positive physical findings alone were not sufficient to result in the elevated neurotic scale scores among patients with a diagnosis of fibromyalgia. Milhous, et al (1989) summarized that "Demographic, job-related, compensation and psychologic factors (as partially reflected in MMPI profiles) were found to be more important than physical factors in predicting ability to return to work" (p.593).
In a persuasive and comprehensive longitudinal study, Bigos, et al (1992) followed 3,020 volunteers at the Boeing Everett plant. The purpose was to assess factors which might predispose employees to file a workers' compensation claim in which they would allege lumbar pain. The factors which had the greatest predictive utility were dissatisfaction with job duties and "distress" as evidenced by an elevation on Scale 3 of the MMPI. Bigos, et al noted that attention to physical factors alone in evaluating a patient with back complaints is not sufficient. They asserted that the factors which might prompt a patient to report physical complaints, might also prompt him / her to have potential problems in making effective use of provided treatment. They concluded that "60-65% of statistically significant factors for predicting acute back injury claims were nonphysical factors" (p.26). Beyond immediate back pain complaints, the factors which carried the greatest weight for whether an individual would submit a complaint of back injury were job dissatisfaction and "certain psychosocial responses identified on the MMPI" (p.27).
Cautionary comments regarding the use of psychological testing include the following:
a) whenever possible, tests should be administered by or under the direct supervision of the testing psychologist
b) care should be taken to ensure standardization of test administration, scoring and interpretation
c) a battery of tests, appropriate to the referral question, should be utilized
d) self-report measures should be interpreted with caution appropriate to the context of the examination
e) optimally, psychological testing should include a clinical interview, a mental status examination, and a review of relevant records by the testing psychologist
f) the consulting psychologist and the medical clinician should discuss their respective findings in detail in order to develop a comprehensive clinical picture of the patient, and to formulate realistic treatment strategies
In summary, psychological assessment, including the use of specific test measures, is a cost effective method for enhancing the understanding of the clinical picture when pain is a primary factor, the issue of motivation, diagnosis and disability, causation, prognosis, prospects for rehabilitation, and treatment needs.
(This material is excerpted from Becker, G. and Smith, R.B. "Psychological Factors in Chronic Back Pain," in Kirkaldy-Willis, W.H. And Bernard, T.H. (Eds) Managing Low Back Pain. Churchill Livingstone, 1999.)
Back to Medical Articles
Home| Appointment by Medical Specialty | Appointment by Physician | Medicare Set-Aside | Life Care Plan | Contact Us | Privacy Statement | Customer Support | © MEDLink SM
|
|
By Medical Specialty