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CHAPTER 23  Multidisciplinary Assessment of Patients with Chronic Pain

prior mastery experience. In chronic pain patients, self-efficacy positively affects physical and psychological functioning, 126,127 and improvements in self-efficacy after self-management and cognitive-behavioral interventions are associated with improve- ments in pain, functional status, and psychological adjustment. Self-report instruments to assess self-efficacy with chronic pain patients have been developed and have been used in both clini- cal research and practice. 128,129 Pain catastrophizing can be defined as an exaggerated nega- tive orientation toward actual or anticipated pain experiences. Current conceptualizations most often describe it in terms of appraisal or as a set of maladaptive beliefs. 130 It is a cognitive and emotional process that involves magnification of pain-re- lated stimuli, feelings of helplessness, and a negative orientation to pain and life circumstances. It includes obsessive rumination about pain, and its meaning and magnification of symptoms also are associated with decreases in pain severity ratings and functional disability. Catastrophizing has been shown to be an important predictor of response to both acute and chronic pain. Catastrophizing have been associated with increased percep- tions of pain severity in both acute 131 and chronic pain severity 132 and disability among groups with diverse pain diagnosis. 132–134 Several self-report measures of catastrophizing have been developed and shown to have good psychometric properties (Coping Strategies Questionnaire [CSQ], 90 Pain Catastroph- izing Scale [PCS] 135 ). These measures have been used in both clinical research and contexts and have shown to have predic- tive validity for disability and response to various treatments. A brief, two-item measure of catastrophizing have been shown to have a high correlation with the longer form and may be useful as a screening device. 136 Assessing Functional Impact A major focus of the discussion earlier has been on the identi- fication of factors underlying the symptoms of a chronic pain patient. It is important to note, though, that the identification of factors that qualitatively play a role in a patient’s symptoms is not the same as an explanation of the severity of these symp- toms or the extent to which the patient is disabled by them. Thus, we recommend that an evaluation of any chronic pain patient should include an assessment of the extent to which the patient is affected by his or her symptoms. When a multidisci- plinary evaluation is conducted, physical therapists, vocational rehabilitation counselors, physicians, and psychologists may participate in the evaluation of function among pain patients. Conceptually, the impact of chronic pain on function can be subdivided into (1) the ability of patients to function in the sense of performing activities of daily living, (2) their physical capacities as demonstrated in a structured setting, and (3) their ability to function in adult roles such as work. 137 Physical functioning and activity can be considered from three complementary perspectives, namely, the patient’s per- spective on his or her functioning (self-report), observation during performance on structure tasks in a clinical or labora- tory setting (e.g., timed walking, gait pattern), and objective as- sessment of activity in the natural occurring environment (e.g., using technical instruments and devices such as accelerome- try). 138,139 Each of these perspectives will provide different infor- mation about performance and are complementary. Objective assessment of physical functioning will depend to some extent on the nature of the physical capacity and diagnostic condition being assessed, and detailed discussions are beyond the scope of this chapter (see Taylor et al. 139 for a comprehensive review). SELF-REPORT MEASURES OF FUNCTION Self-report measures have been developed to assess people’s reports of their abilities to engage in a range of functional

activities such as the ability to walk up stairs, sit for specific periods of time, lift specific weights, and perform activities of daily living as well as the severity of the pain experienced upon the performance of these activities. 139 There are a num- ber of well-established, psychometrically supported generic (e.g., Short-Form 36 [SF-36]), 140 pain-specific (e.g., BPI Inter- ference Scale, 92 Pain Disability Index [PDI], 141 MPI Interfer- ence Scale), and diagnosis back pain–specific (Oswestry Low Back Pain Disability Questionnaire [OLBPQ], 91 Western On- tario McMaster Assessment of Knee and Hip Osteoarthritis [WOMAC]) 142 measures of functional status (for a review, see Taylor et al. 139 ). The OLBPQ is a widely used, 10-item scale that asks pa- tients about disability associated with back pain. 91 It has the advantage of being a disease-specific instrument. In general, disease-specific measures are designed to evaluate the specific effects of a disorder that may not be assessed by a generic mea- sure. 138,139 In addition, responses on disease-specific measures will generally reflect the effects of comorbid conditions on physical functioning, which may confound the interpretation of change occurring over the course of a trial when generic mea- sures are used. Disease-specific measures may be more sensitive to the effects of treatment on function, but generic measures provide information about physical functioning and treatment benefits that can be compared across different conditions and studies. 139,143 Each of these approaches has strengths. Decisions regarding whether to use a disease-specific or a generic mea- sure, or some combination, will depend on the purpose of the assessment. For individual patients in clinical practice, it would be most appropriate to use measures developed on samples with comparable characteristics. If the clinician wishes to com- pare across a group of patients, then one of the broader based pain-specific measures should be considered. If the assessment is being performed as part of a research study, some combi- nation might be appropriate to compare chronic pain samples with a larger population of people with diverse medical dis- eases (e.g., SF-36). A particularly important aspect of physical functioning that is particularly important to those with chronic pain is sleep. 50 Pain is frequently reported as have a significant impact on sleep quality as well as duration. 144 Patients being evaluated should be asked about their sleep, and depending on the information acquired during an interview, more detailed methods are avail- able to assess sleep objectively using formal sleep laboratory evaluation, accelerometry, and self-report measures (e.g., Med- ical Outcomes Study [MOS] Sleep Scale). 145 Assessment of Physical Capacity The physical capacities of pain patients are typically assessed by physical and occupational therapists. In some clinical set- tings, evaluation protocols are developed informally by indi- vidual therapists, sometimes in conjunction with a physician. In other settings, formal assessment protocols are used. Although the validity of such protocols has been questioned, 139 they are frequently used—particularly when injured workers are being evaluated. The purpose of such evaluations is to obtain objec- tive information about the capabilities of patients. In clinical settings, this information is used in the planning of rehabilita- tive treatment. In more adversarial settings (e.g., workers’ com- pensation), physical capacities data are used when adjudicative decisions about claims are made. Ideally, a multidisciplinary evaluation would include hav- ing a vocational rehabilitation counselor perform a compre- hensive evaluation of the work status of pain patients and their potential for vocational rehabilitation. In many situa- tions, though, the job of assessing vocational disability falls on the physician or psychologist on the multidisciplinary team.