Pain Measurement

CHAPTER 6 PAIN MEASUREMENT



W. Crawford Clark, PhD, Sita S. Chokhavatia, MD, Abbas Kashani, MD, Susanne Bennett Clark, PhD




DIMENSIONS OF PAIN



1. Name the five axes of pain according to the taxonomy devised by the International Association for the Study of Pain


The taxonomy devised by the International Association for the Study of Pain lists the following five axes of pain:



image Regions of the body


image Systems affected


image Temporal characteristics


image Intensity and time since onset


image Etiology



2. Which major aspects or dimensions of pain and suffering must be considered when assessing pain? Define the dimensions


Melzack and Casey argue for the following three dimensions of pain: (1) The sensory-discriminative dimension comprises the sensory aspects of pain, including intensity, location, and temporal aspects. (2) The affective-motivational dimension reflects the emotional and aversive aspects of pain and suffering. (3) The cognitive-evaluative dimension reflects the patient’s evaluation of the meaning and possible consequences of the pain and illness or injury, including impact on quality of life and even death itself. This three-dimensional model is widely accepted because it integrates much of what is known about the physiology and psychology of pain and suffering.



PAIN SCALES



3. Name three accepted types of scales for measuring the intensity of pain




image Visual analogue scale


image Numerical rating scale


image Category rating scale



4. Describe the analogue, numerical, and category scales. Which is most suitable for use with patients?


Visual analogue scales (VAS) are 10-cm lines anchored at the ends by words that define the bounds of various pain dimensions. The patient is asked to place a vertical mark on the scale to indicate the level of intensity of his or her pain, anxiety, depression, etc. The following are two VAS examples:










No Pain Worst Possible Pain
No Anxiety Worst Possible Anxiety

Numerical rating scales are similar to analogue scales except that numbers (e.g., 0 to 5) are entered along the scale.


With category scales, the patient is asked to circle the word that best describes his or her condition (e.g., for pain intensity: None, Moderate, Severe, Unbearable).


Each of the presented scales may be appropriate for patients.



5. What is the “fifth vital sign” to be entered in the patient’s chart?


The fifth vital sign is the rating score on a unidimensional pain scale. It is entered in the patient’s chart along with respiration, blood pressure, heart rate, and temperature.



6. What does a score obtained from the unidimensional pain scale mean?


The unidimensional pain scale score is supposed to reflect the intensity of the patient’s physical (sensory) pain. However, it has been demonstrated that the score on a pain rating scale is not, as one might expect, related only to the intensity of somatosensory aspects of physical pain, but also to the intensity of emotional aspects of pain, including the patient’s anxiety, fear, depression, and anger.



7. What is the solution to the pain assessment problem described in question 6?


Scores on additional emotional scales related to anxiety, fear, depression, and anger must be obtained and factored into any decision about the level of the patient’s pain.



8. What is the difference between a rating scale and a questionnaire?


A rating scale represents a single dimension related to some aspect of pain or suffering; a questionnaire contains a large number of rating scales that encompass many dimensions of pain and related emotions.



PAIN ASSESSMENT BY QUESTIONNAIRES



9. How is pain/emotion assessment accomplished? Why is it important?


Pain assessment is a multidimensional approach to the evaluation of pain attributes. These attributes include the intensity, duration, and location of pain and its somatosensory and emotional qualities. It is important because meticulous assessment is needed to tailor the patient’s medication and dosage to his or her particular requirements; for example, to decide whether an analgesic should be supplemented with an anxiolytic, antidepressant, and/or psychotherapy. Careful evaluation also permits changes in medication to be monitored reliably.



10. What is the most widely used pain questionnaire?


The McGill Pain Questionnaire, which has been translated into all major languages, was developed by Dr. Ronald Melzack of McGill University. It is a checklist of 87 descriptors of the sensory qualities of a patient’s pain and related emotions, plus a line drawing of a body on which the patient sketches the location of the pain. The questionnaire also includes an overall intensity rating called the Present Pain Index.



11. Describe the multidimensional affect and pain survey (MAPS)


The 101 descriptors of the Multidimensional Affect and Pain Survey (MAPS) questionnaire are grouped into 30 subclusters subordinated within three superclusters. Supercluster I, Sensory Pain, contains 57 descriptors of painful sensory qualities in 17 subclusters. Supercluster II, Emotional Pain (Suffering), contains 26 descriptors of negative emotional states in eight subclusters. Supercluster III, Well-Being, contains 18 descriptors of positive affect and health in five subclusters. The descriptors are placed in sentences to clarify their meaning. The patient rates these statements on a response scale that ranges from Not at All (0) to Very Much So (5).


Here are examples from each of the three MAPS superclusters:



















I. Sensory Qualities Supercluster
   The sensation and/or pain is BURNING 0 1 2 3 4 5
II. Suffering Supercluster
   I feel DEPRESSED 0 1 2 3 4 5
III. Well-Being Supercluster
   I feel CALM 0 1 2 3 4 5


12. Can administration of MAPS before surgery predict postoperative morphine consumption?


Yes, patients who before surgery anticipate greater pain and emotional distress actually consume more morphine postoperatively.



13. What is the advantage of knowing the relative intensities of the sensory and emotional components that determine patients’ ratings of “pain”?


If the relative strengths of the sensory and emotional components are known, medication (analgesics, anxiolytics, antidepressants) can be tailored more accurately to the patient’s needs.



14. Why is MAPS superior to other questionnaires?


The MAPS structure was determined objectively, by cluster analysis. The 101 items of MAPS were selected from an initial set of 270 descriptors by means of the pile-sort procedure. This procedure is based on pair-wise similarity judgments of the descriptors by healthy volunteers. The data were analyzed by the agglomerative, hierarchical clustering technique, using the average-linkage-between-groups algorithm. Descriptors that were highly similar according to cluster analysis, and descriptors that had different meanings (i.e., fell into different clusters) for female and male college students of Puerto Rican, Euro-American, and African-American background, were eliminated. Thus, the MAPS questionnaire was based on a dendrogram of 101 words that, unlike other questionnaires, is relatively free of gender and ethnocultural bias. These descriptors, clustered according to their location in the dendrogram, determine the structure of the MAPS.



15. What are the three main advantages of MAPS?


The main advantages of MAPS over the McGill Pain Questionnaire are as follows:



image The hierarchical organization of clusters within the three superclusters and of the pain descriptors within the subclusters is determined objectively from a large sample of volunteers, not subjectively from the diverse opinions of pain “experts.”


image The large number of words describing the emotional aspects of pain shortens test time by eliminating the need for additional psychologic questionnaires to probe the patient’s emotional state.


image The Well-Being Supercluster identifies an interesting subset of patients who say they are depressed and relaxed at the same time. Patients who respond in this manner may be those who are denying their pain because they fear that it may indicate a serious illness.



16. What is the Brief Pain Inventory (BPI)?


The Brief Pain Inventory (BPI) measures both the intensity of the pain (sensory component) and the interference of the pain in the patient’s life. Originally developed by a group focusing on cancer pain, the BPI is now one of the most commonly used pain assessment tools for all types of pain for both clinical and research purposes.



PAIN-RELATED QUESTIONNAIRES



17. How is pain assessed in patients who, because of neurological or cognitive deficits, cannot communicate verbally?


Pain in cognitively impaired patients and young children can be estimated by their responses to a scale consisting of a series of faces whose expressions range from smiling to discomfort to desperate crying. Patients indicate their pain by pointing to one of the faces. Recently, the Iowa Pain Thermometer has been developed to assess pain in younger patients, as well as in older adults. This scale is being increasingly used in practice.



18. True or false: scores from questionnaires on emotional symptomatology (e.g., the Brief Symptom Inventory) can be relied upon when given to patients who are suffering pain


False. Scores from such questionnaires must be interpreted with caution. Test items that reflect depression in psychiatric patients (e.g., loss of appetite) may be due to a physical condition such as ulcers or may result from treatment, for example with narcotics, in medical patients. Accordingly, a medical patient with a high score on a test of psychologic status could be misdiagnosed as having a “psychological” problem.



19. Which questionnaires are used to assess the general psychologic status of pain patients?


The Derogatis Symptom Check List-90 (SCL-90) or its shorter version, the Brief Symptom Inventory (BSI), is often used to assess the psychologic status of pain patients. Patients use the lists to score how much they are bothered by a particular symptom. The Profile of Mood States (POMS) is also frequently used, because its questions do not allude to florid psychotic behavior.



20. What is the effect on the physician-patient relationship when giving the patient a psychologic status questionnaire?


Many patients resent being given a questionnaire that was obviously designed for psychiatric patients because it gives the impression that the physician does not believe that their pain is “real.”



21. Which standardized questionnaires can be used to assess physical function?


Disability is assessed by the Health Assessment Questionnaire, the Sickness Impact Profile, and the Arthritis Impact Measurement Scale. Other scales measure social and work satisfaction, ambulation, and self-care. The Karnofsky scale is a behavioral scale widely used to assess the stages of disease progression in cancer patients. Many of these scales yield a score that locates the patient relative to population norms.



22. What are the seven ways, quantified in the Coping Strategies Questionnaire, that patients use to cope with their pain? Can patients be taught these strategies?

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Jun 14, 2016 | Posted by in PAIN MEDICINE | Comments Off on Pain Measurement

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