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CHAPTER 23  Multidisciplinary Assessment of Patients with Chronic Pain

information about behaviors that may be private (sexual re- lations) or unobservable (thoughts, emotional arousal), and, most importantly, have been submitted to analyses that permit demonstration of their psychometric properties (e.g., reliability and validity). These instruments should not be viewed as alter- natives to interviews; rather, they are complements that may suggest issues to be addressed in more depth during an inter- view or investigated with other measures. There is an important caveat when interpreting the results of patient self-report inventories. Studies of the psychometric properties of these inventories typically involve data collection from a large number of patients. As reliability estimates are influenced by sample size, it follows that the measurement error of questionnaire data from one person should be expected to be much greater than that found in reports based on group data. Self-report measures of pain often ask patients to quantify their pain by providing a single, general rating of pain: “Is your usual level of pain ‘mild,’ ‘moderate,’ or ‘severe’?” or “Rate your typical pain on a scale from 0 to 10 where 0 equals no pain and 10 is the worst pain you can imagine.” There are a number of simple methods that can be used to evaluate pain intensity—Numerical Rating Scale (NRS), Verbal Ratings Scale (VRS), and Visual Analog Scale (VAS) using different variation. For example, the Brief Pain Inventory (BPI) includes four indi- vidual questions using NRSs—right now, pain on average, pain at worst, and pain at least. 92,93 Each of the commonly used methods of rating pain in- tensity, NRS, VRS, and VAS, appear sufficiently reliable and valid, and no one method consistently demonstrates greater responsiveness in detecting improvements associated with pain treatment. 94,95 However, there are important differences among NRS, VRS, and VAS measures of pain intensity with respect to missing data stemming from failure to complete the measure, patient preference, ease of data recording, and ability to admin- ister the measure by telephone or with electronic diaries. NRS and VRS measures tend to be preferred over VAS measures by patients, and VAS measures usually demonstrate more missing data than do NRS measures. Greater difficulty completing VAS measures is associated with increased age and greater opioid intake, and cognitive impairment has been shown to be associ- ated with inability to complete NRS ratings of pain intensity. 95 Patients who are unable to complete NRS ratings may be able to complete VRS pain ratings (e.g., none, mild, moderate, se- vere). Other measures are available to assess pain in children and those who are unable to verbally communicate (e.g., stroke patients, mentally impaired). 96,97 There has been some concern expressed that retrospective re- ports may not be valid, as they may reflect current pain sever- ity that serves as an anchor for recall of pain severity over some interval. 98,99 More valid information may be obtained by asking about current level of pain, pain over the past week, worst pain of the last week, and lowest level of severity over the last week (e.g., BPI). This has also led to the use of daily diaries that are believed to be more accurate as they are based on real time rather than re- call. For example, patients are asked to maintain regular diaries of pain intensity with ratings recorded several times each day (e.g., at meals and bedtime) for several days or weeks. One problem noted with the use of paper-and-pencil diaries is that patients may not follow the instruction to provide ratings at specified intervals. Rather, patients may complete diaries in advance (“fill forward”) or shortly before seeing a clinician (“fill backward”). 99,100 These two reporting approaches undermine the putative validity of di- aries. As an alternative to the paper-and-pencil diaries, a number of commentators have advocated for the use of electronic devices that can prompt patients for ratings and “time stamp” the actual PROBLEM AREAS TO ASSESS Assessment of Pain Pain Intensity

ratings, thus facilitating real-time data capture. 100–102 Although there are numerous advantages to the use of advanced technol- ogy to improve the validity of patient ratings, they are not with- out potential problems, including hardware problems, software problems, and user problems. 103 These methods are also costly, and although they may be appropriate for research studies, their usefulness in clinical settings may be limited. Pain Quality Pain is known to have different sensory and affective qualities in addition to its intensity, and measures of these components of pain may be used to more fully describe an individual’s pain experience. It is possible that the efficacy of pain treatments varies for different pain qualities, and measures of pain quality may therefore identify treatments that are efficacious for certain types of pain but not for overall pain intensity. Assessment of specific pain qualities at baseline also makes it possible to deter- mine whether certain patterns of pain quality moderate the ef- fects of treatment. The Short-Form McGill Pain Questionnaire (SF-MPQ) 86 assesses 15 sensory and affective pain descriptors, and its sensory and affective subscales have demonstrated re- sponsivity to treatment in a number of clinical trials. 104 More recently, a revision of the SF-MPQ (SF-MPQ-2) was developed to increase the range of items (rated on a 0-to-10 scale) and items added to assess characteristics of neuropathic pain that have been not been adequately assessed in the SF-MPQ. 105 Pain Modifiers For the majority of people with chronic pain, pain severity var- ies. Thus, it is useful to inquire as to what the patient believes makes his or her pain worse. For example, are their specific activities that result in increase in symptoms? Are their certain circumstances that contribute to exacerbation of pain such as stress including interpersonal conflicts? Does pain vary with time of day? For example, does the patient notice that his or her pain is worse in the morning or later in the day? In the same way, it is important to identify factors that magnify or initiate pain episodes; it is important to ask about what factors result in reductions of pain. For example, does medication, rest, heat or cold, distraction, or exercise result in reductions of pain severity or even elimination of symptoms for some period? Pain may be influenced by the context or activities being un- dertaken. For example, pain intensity when an individual is at rest may differ substantially from pain experienced during movement. Thus, it is important to address what factors mod- ify pain such as the nature of different activities. Assessment of Overt Expressions of Pain As noted previously, patients display a broad range of responses that communicate to others that they are experiencing pain, distress, and suffering. Some of these pain behaviors may be consciously controllable by the person, whereas others are not. Informally, a health care provider can observe patients’ behav- iors during their interviews and examinations. It is useful to ob- serve patients in multiple contexts when possible (e.g., waiting room, ambulating to an exam room, during interview with cli- nician, during physical examination). When patients know they are being observed and are presenting information to a health care provider, they may use behavior to convey information in ways most likely to support the impact of their symptoms. They may feel a need to convince the health care provider of the sever- ity of their symptoms, functional limitations, and distress. Thus, observation of the patient in the waiting room, when ambulat- ing to the examination room, and when departing may allow the clinician to establish the stability and consistency of pain be- haviors. We have also found it useful to observe patients in the presence of a significant other to note differences in behaviors when the significant other is present and absent and also how the significant other responds to the patient’s pain behaviors.