Case Report: Phantom limb pain relief after cognitive multisensory rehabilitation

Pain intensity is frequently measured on an 11-point pain intensity numerical rating scale (PI-NRS), where 0=no pain and 10=worst possible pain. However, it is difficult to interpret the clinical importance of changes from baseline on this scale (such as a 1- or 2-point change). To date, there are no data driven estimates for clinically important differences in pain intensity scales used for chronic pain studies. We have estimated a clinically important difference on this scale by relating it to global assessments of change in multiple studies of chronic pain. Data on 2724 subjects from 10 recently completed placebo-controlled clinical trials of pregabalin in diabetic neuropathy, postherpetic neuralgia, chronic low back pain, fibromyalgia, and osteoarthritis were used. The studies had similar designs and measurement instruments, including the PI-NRS, collected in a daily diary, and the standard seven-point patient global impression of change (PGIC), collected at the endpoint. The changes in the PI-NRS from baseline to the endpoint were compared to the PGIC for each subject. Categories of "much improved" and "very much improved" were used as determinants of a clinically important difference and the relationship to the PI-NRS was explored using graphs, box plots, and sensitivity/specificity analyses. A consistent relationship between the change in PI-NRS and the PGIC was demonstrated regardless of study, disease type, age, sex, study result, or treatment group. On average, a reduction of approximately two points or a reduction of approximately 30% in the PI-NRS represented a clinically important difference. The relationship between percent change and the PGIC was also consistent regardless of baseline pain, while higher baseline scores required larger raw changes to represent a clinically important difference. The application of these results to future studies may provide a standard definition of clinically important improvement in clinical trials of chronic pain therapies. Use of a standard outcome across chronic pain studies would greatly enhance the comparability, validity, and clinical applicability of these studies.

The McGill Pain Questionnaire consists primarily of 3 major classes of word descriptors--sensory, affective and evaluative--that are used by patients to specify subjective pain experience. It also contains an intensity scale and other items to determine the properties of pain experience. The questionnaire was designed to provide quantitative measures of clinical pain that can be treated statistically. This paper describes the procedures for administration of the questionnaire and the various measures that can be derived from it. The 3 major measures are: (1) the pain rating index, based on two types of numerical values that can be assigned to each word descriptor, (2) the number of words chosen; and (3) the present pain intensity based on a 1-5 intensity scale. Correlation coefficients among these measures, based on data obtained with 297 patients suffering several kinds of pain, are presented. In addition, an experimental study which utilized the questionnaire is analyzed in order to describe the nature of the information that is obtained. The data, taken together, indicate that the McGill Pain Questionnaire provides quantitative information that can be treated statistically, and is sufficiently sensitive to detect differences among different methods to relieve pain.

To benefit from mental practice training after stroke, one must be able to engage in motor imagery, and thus reliable motor imagery assessment tools tailored to persons with sensorimotor impairments are needed. The aims of this study were to (1) examine the test-retest reliability of the Kinesthetic and Visual Imagery Questionnaire (KVIQ-20) and its short version (the KVIQ-10) in healthy subjects and subjects with stroke, (2) investigate the internal consistency of both KVIQ versions, and (3) explore the factorial structure of the two KVIQ versions. The KVIQ assesses on a five-point ordinal scale the clarity of the image (visual: V subscale) and the intensity of the sensations (kinesthetic: K subscale) that the subjects are able to imagine from the first-person perspective. Nineteen persons who had sustained a stroke (CVA group) and 46 healthy persons (CTL group) including an age-matched (aCTL: n = 19) control group were assessed twice by the same examiner 10 to 14 days apart. The test-retest reliability was assessed using intraclass correlation coef- ficients (ICCs). The internal consistency (Cronbach alpha) and the factorial structure of both KVIQ versions were studied in a sample of 131 subjects. In the CVA group, the ICCs ranged from 0.81 to 0.90, from 0.73 to 0.86 in the aCTL group, and from 0.72 to 0.81 in the CTL group. When imagining movements of the affected and unaffected limbs (upper and lower limbs combined) ICCs in the CVA group ranged, respectively, from 0.71 to.87 and from 0.86 to 0.94. Likewise, when imagining movement of the dominant and nondominant limbs, ICCs in the aCTL group ranged, respectively, from 0.75 to 0.89 and from 0.81 to.92. Cronbach a values were, respectively, 0.94 (V) and 0.92 (K) for the KVIQ-20 and 0.89 (V) and 0.87(K) for the KVIQ-10. The factorial analyses indicated that two factors explained 63.4% and 67.7% of total variance, respectively. Both versions of the KVIQ present similar psychometric properties that support their use in healthy individuals and in persons post-stroke. Because the KVIQ-10 can be administered in half the time, however, it is a good choice when assessing persons with physical disabilities.