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Research Reports |
A Kvåle, PT, PhD, is Assistant Professor, Section for Physiotherapy Science, Department of Public Health and Primary Health Care, Faculty of Medicine, University of Bergen, Bergen, Norway
JS Skouen, MD, PhD, is Clinical Director, The Outpatient Spine Clinic, Department of Physical Medicine and Rehabilitation, Haukeland University Hospital, Bergen, Norway, and Assistant Professor, Section for Physiotherapy Science, Department of Public Health and Primary Health Care, Faculty of Medicine, University of Bergen
AE Ljunggren, PT, PhD, is Professor, Section for Physiotherapy Science, Department of Public Health and Primary Health Care, Faculty of Medicine, University of Bergen
Address all correspondence to Dr Kvåle at Section for Physiotherapy Science, Faculty of Medicine, University of Bergen, Kalfarveien 31, 5018 Bergen, Norway (alice.kvale{at}isf.uib.no)
Submitted December 19, 2003;
Accepted February 22, 2005
| Abstract |
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Key Words: Measurement Movement Muscle Posture Respiration Responsiveness Skin Work status
| Introduction |
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In the Scandinavian countries, there is a physical therapy approach called Norwegian Psychomotor Physical Therapy (NPPT).10,11 The NPPT approach is based on the theory that patients with long-lasting problems, physical or psychological, may react with general aberrations related to posture, respiration, and movement, as well as with muscular tension and skin changes.1214 From this therapy approach, an examination method called the Global Physiotherapeutic Muscle Examination (GPM) was developed by Sundsvold and coworkers1317 in order to document where and to what degree physical changes occur. The GPM-78 has 78 standardized tests that cover examination within 5 main domains: posture, respiration, movement, muscle, and skin.16,18,19 These main domains are divided into 13 subdomains, each with 6 tests. Within the posture domain, postural items are inspected in both standing and supine positions. Within the respiration domain, inspiration amplitude of abdominal and thoracic areas is inspected in both standing and supine positions. Within the movement domain, passive range of motion of the head and the extremities is measured with a goniometer or in centimeters, flexibility and ability to relax are tested by means of passive movements performed by the therapist, and different active movements are performed by the patient. Included in the examination of the muscle domain are stretch and pressure palpation and the patient's verbal reaction to the stretching maneuver performed by the therapist. The skin domain is examined through pressure and stretch palpation in the same areas as in the examination of muscles.
Each item is scored according to how it relates to a predefined standard, corresponding to the score of 0. Table 1 illustrates the scoring scale. All except 3 items are bipolar; that is, they can be either increased or decreased. These items are scored on a 15-point scale ranging from -2.3 to +2.3 and denote the quantity and direction of deviation away from the predefined standard. The 2 directions give clinical information, whereas absolute values indicate magnitude of problems. Summations of the absolute test scores comprise the basis for a total score, 5 main domain sum scores, and 13 subdomain sum scores.
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Development of all GPM versions was based on patients who mainly had psychiatric or psychosomatic problems. Consequently, the construct validity was recently examined on data from people who were healthy and patients with long-lasting musculoskeletal pain.2428 In order to meet the demands for a reliable and valid examination method, a modified and shorter version of the GPM-78, called the Global Physiotherapy Examination (GPE-52), was developed. Based on data from 351 people, a form of confirmatory factor analysis called "structural equation modeling" was performed.29 Confirmatory factor analysis can be used to revise and refine already existing instruments.30 It enables the researchers to test whether relationships expected on theoretical grounds actually appear in the data. One domain of the GPM-78 was examined at the time and then modified until the model fitted adequately, while still seeming clinically meaningful. Items that correlated too closely with each other or added little information were identified and omitted. The new version still has 5 main domains, but there are 4 items instead of 6 in each of the 13 subdomains. The items and domains of the GPE-52 are shown in the scoring form (Appendix). An examination takes about 30 minutes. Learning the complete GFM-52 takes 3 days, although clinical practice is recommended before it can be used reliably.
The GPE-52 has been found applicable to patients with all types of long-lasting musculoskeletal problems (eg, neck pain, low back pain, fibromyalgia) and is a useful generic examination instrument, especially for patients with chronic pain.27 Posture, respiration, movements, and muscles function interactionally; a common pitfall is to overlook this interaction and concentrate only on the part of the body that the patient has reported as being most painful.11,14 Previous research indicates high scores in patients with extensive physical or psychological problems.31 Furthermore, it has been demonstrated that the GPE-52 discriminates between patients with long-lasting musculoskeletal problems and people who are healthy and between patients with localized versus widespread pain.27 Previous studies27,28 demonstrated mean total GPE-52 scores of around 34 (SD=6.4) in subjects who were healthy as compared with 47 (SD=8.0) in patients with long-lasting musculoskeletal pain problems. Studies including patients with psychiatric disorders have resulted in much higher GPM-78 mean values.14 The maximum total GPE-52 score is 119.6 (2.3 x 52).
Measures intended to be used as instruments in evaluative studies should be sensitive to change (have the ability to measure any change in health status), as well as show responsiveness (the ability to detect meaningful change).32,33 Little seems to have been published regarding these aspects for comprehensive physical assessment batteries. The sensitivity to change and the responsiveness of the GPE-52 have not been formerly studied. The purpose of this study was to examine these aspects by measuring where and to what extent different groups of patients with long-lasting musculoskeletal pain change physical qualities over time. The GPE-52 may be useful for pretreatment examination; however, all domains may not be equally useful as outcome measures in intervention studies.
| Method |
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Subjects
The patients participated in a longitudinal randomized controlled trial with a large study sample.34 The patients who were assigned randomly to the clinical intervention part constituted our study sample. Two hundred forty-seven consecutive patients were examined by the GPE-52 (159 women, mean age=44.2 years, SD=10.0, range=22-66; 88 men, mean age=42.5 years, SD=11.1, range=24-64). The patients had been on sick leave from their work for an average of 3.3 months (SD=2, range=1-20) due to long-lasting musculoskeletal problems, but all had had pain for much longer.
Only patients without specific underlying systemic disease or pathology and without substance abuse were included, and a specialist in neurology diagnosed all patients as having problems related to the musculoskeletal system.34 The patients' primary diagnosis could be grouped into 4 broad categories upon entry into the rehabilitation program: 9.3% had a diagnosis related to the neck or shoulder, 49.4% had a diagnosis related to low back pain, 22.7% had a diagnosis related to general muscular pain, and 18.6% had other diagnoses related to the musculoskeletal system. At the posttreatment examination 4 weeks later, 225 (64% women) were examined. Of those patients, 216 (68% women) were examined 6 months after discharge. The intention was to re-examine all patients 18 months after discharge, but because a new project started at the clinic, there was no capacity for physical re-examinations. Only the first 61 patients (67% women) were examined at 18 months. Work status data at 18 months, however, were available for about 90% of the patients.
The patients' work status was followed by the Norwegian national medical insurance, which registers sickness episodes longer than 2 weeks and all payments from the benefit scheme that covers all economically active individuals, except civil servants (about 8.5%-10%). Work status was registered on all of the 247 patients included in the study, except for 14 patients (civil servants), at both 6- and 18-month follow-up examinations. Subjects were categorized as either working or not working. Thus, people on vocational rehabilitation, partly working and partly on sick leave, or receiving any form of benefit were registered as not working. Patients whose work status data were lacking were excluded from relevant analyses.
Categorization of Patients According to Pain Drawing
Because many patients also had pain in other areas than the location of their main problem, a simple procedure was chosen to categorize the patients into 3 groups.31,35 In order to map the distribution of pain, the patients marked on a pain drawing the area(s) that had been painful during the last 14 days before starting treatment. The number of squares marked was counted, and patients were categorized according to where they had marked pain. Patients who had pain above a horizontal line in the thoracolumbar region (T12) constituted group 1 (n=34: 79% women). Patients with pain only below the horizontal line constituted group 2 (n=58: 48% women). Those with pain both above and below the line were included in group 3 (n=134: 68% women), and such pain was defined as widespread. Markings either above or below the line were defined as localized.31,3639 Patients with localized pain, on average, marked 13.5 (SD=8.4) squares with pain, whereas those with widespread pain marked 30.3 (SD=18.1) squares with pain. For unknown reasons, a pain drawing was not registered for 21 patients.
Physical Findings
In this study, the patients were examined with the GPE-52 by a physical therapist upon admission, and the same physical therapist performed the follow-up examinations. Data from former examinations were not available to the physical therapist at the follow-up examinations, and the physical therapists were unaware of the pain category group to which the patient belonged. Three physical therapists participated. One of them used the measurement tool for about 6 years, whereas the others used it only occasionally for 1 year, after completion of a 1-week course. To ensure that the examiners were equally familiar with the examination procedures and criteria for scoring, they underwent 25 hours of intensive training and then performed an intertester reliability study of 19 people prior to this longitudinal study. Acceptable relative and absolute reliability were achieved.28 The intraclass correlation coefficient (ICC [2,1]) was .91 for the total GPE-52 score, with a measurement error (sw) of 3.1. The ICC for the posture domain was .65, with an sw of 1.1. Within the respiration domain, the ICC was .60, due to limited range in scores, and the sw was 1.1.24 Within the movement domain, the ICC was .89, with an sw of 1.6.25 Within the muscle domain, the ICC was .83, with an sw of 1.4, and within the skin domain the ICC was .76, with an sw of 1.1.26 The sw was generally
0.8 for the subdomains.
Intervention
When the evaluation process was completed, a multidisciplinary cognitive behavioral treatment program was developed, based on individually adapted functional restoration principles.34 The intensive treatment period lasted 6 hours daily, 5 days a week for 4 weeks, with follow-up at regular intervals for 1 year. The program included treatment of patients in groups of 12, with daily intensive physical and ergonomic training, body awareness and relaxation training, psychological pain management, and teaching and talks about biopsychosocial issues. Workplace-based intervention was offered when deemed necessary.
Data Analysis
In this study, parametric statistics were used, as the sample was large, and the assumption of normal distribution was met for the GPE-52 (Kolmogorov-Smirnov test, P >.05, skewness <1). Analyses of variance (ANOVAs), with post hoc contrasts using the Scheffé procedure to determine pair-wise group differences, and t tests were used to test for initial differences among groups and between groups of patients who were and who were not working at the 6- and 18-month follow-up examinations. Sensitivity to change measured within each patient group was measured with paired t tests. At 18 months, the sample size did not allow for categorization between patients with localized versus widespread pain. Responsiveness to important change was examined by comparing those working and not at the 6- and 18-month follow-up examinations.
Logistic regression (LR) was used to predict the risk of not returning to work, where odds ratios (ORs) of >1 indicate an increased risk of not working. Unconditional LR was used with work status as the dependent variable and the GPE scores as the independent variable,40 where the GPE scores were transformed into 3 categories (33 percentiles), using the lowest category as reference value. Effects were reported as ORs with corresponding confidence intervals (CIs) for the total sample at 6 and 18 months.
This study did not focus on possible age and sex differences regarding physical change over time, and these variables therefore were controlled for in the LR analysis. Both factors have been reported to affect complaints and physical findings, especially movement.4143 Because age did not affect the results in our study, this factor was not included in the final analysis. The simple subtraction of average posttreatment scores from pretreatment scores assumes that change will be the same, except for random error, for all patients. To control for the effect called "regression to the mean scores," the pretreatment scores also were entered as covariates.40
Responsiveness to change was also measured by calculating effect size (ES). Effect size is defined as the mean change from pretest to follow-up found in a variable, divided by the standard deviation of that variable at pretest.44 Effect size was used to translate magnitude of change into a standard unit of measurement that might provide a clearer understanding of health status results.32 An ES of 0.2 is considered small, 0.5 medium, and 0.8 represents a large ES.45,46 An ES of 0.5 indicates that the mean between the 2 examinations differs by half a standard deviation.
| Results |
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Total sample.
In the total sample at the pretreatment examination, there were no differences in total mean GPE-52 score between the 2 groups categorized according to work status at 6 months, but those subjects who had returned to work at 6 months initially had fewer problems in the movement domain than those who had not returned to work at 6 months (t=-2.1, df=202, P=.034). Logistic regression analysis showed that the risk of not having returned to work at 6 months increased with higher GPE-52 total scores at that time (Tab. 3). Using scores below 37.5 as the reference value, the OR for not having returned to work was 2.2 (95% CI=0.97-4.80) when GPE-52 total scores at the 6-month follow-up examination were between 37.5 and 45; the OR for not having returned to work was 4.6 (95% CI=1.5-13.9) when scores at the 6-month follow-up examination were higher than 45. An increased risk of not working also was found with increasing scores in the movement domain. Patients with a movement domain score between 9.7 and 14.5 were 2.8 (95% CI=1.3-6.1) times more likely to be sick-listed compared with the reference group (scores <9.7), and the OR was 3.9 (95% CI=1.4-11.0) with scores above 14.5. The P value for high scores in the respiration domain was .10. In the respiration, movement, and muscle domains, the magnitude of change from the pretreatment examination to the 6-month follow-up examination was slightly larger measured with ES in those subjects who were working at 6 months compared with those who were still sick-listed (0.2-0.3 higher ES).
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Group 3.
Before treatment, the group later registered as working had lower mean total GPE-52 scores (P=.037) and fewer aberrations in movement (P=.001) compared with those who were not working (Tab. 4). At the 6-month follow-up examination, there were no longer any differences when we controlled for age, sex, and pretreatment values. Small differences in ES values were registered in group 3 between patients who were working and those who were not working (Fig. 2).
Patients who were examined at 18 months and registered as working at that time (n=24) had no physical differences at the pretreatment examination compared with those who were later registered as not working (n=35). At 18 months, patients who were working had fewer aberrations in the respiration and movement domains compared with the nonworking group, and the magnitude of change from the pretreatment examination to 18-month follow-up examination is illustrated in Figure 3. Odds ratios for not working were 4.2 (95% CI=0.9-18.6) for the middle category of GPE-52 total scores compared with the reference group and 5.5 (95% CI=0.9-34.5) for the highest category (Tab. 3). In the respiration domain, the risk was 2.9 (95% CI=0.7-11.7) for not having returned to work with scores in the middle category and 5.7 (95% CI=1.4-22.8) in the highest category compared with the reference group (who had scores <5.8). In the movement domain, the OR for not working at 18 months was 5.3 (95% CI=0.7-38.6) in patients with scores in the highest category (>14) compared with patients with scores in the lowest category (<9.4).
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| Discussion |
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Responsiveness of the GPE-52 was demonstrated to some extent. Patients who returned to work obtained a larger magnitude of physical change compared with those still receiving work benefits; however, as illustrated in Figure 2, the difference in change between those who were working and those who were not working was most obvious in those patients with localized pain. The movement and respiration domains were shown to be responsive to clinically important change, and the findings in our study support the application of these domains as outcome measures in intervention studies. The movement domain showed interesting, although mixed, results. For the total sample, responsiveness was demonstrated, as indicated by the logistic outcome, and the odds of not having returned to work increased with increasing score categories. The findings were significant at 6 months, but at 18 months the sample size was too small, showing the same trend without statistical significance in the movement domain. The muscle domain scores did not show significant responsiveness in the logistic regression analysis, and, measured with ES, the difference between patients who were working and those who were not working was small. The posture domain scores differed little between patients who were working and those who were not working, and the skin domain showed no sign of responsiveness. Patients with long-lasting musculoskeletal pain, however, may not change much regarding posture and skin, as measured in this study.
In patients with pain initially localized only to the upper body (group 1), clinically important change, in this study measured in relation to work status, seemed to have occurred within the respiration and muscle domains, measured from the pretreatment examination to the 6-month follow-up examination (Fig. 2). Patients who later returned to work initially had more muscular problems, but obtained a moderate to large degree of change, indicated by effect size, in contrast to patients who remained on sick leave. Restrained basic respiration has been seen as a cause of recruiting auxiliary musculature, over time perpetuating problems.49 One cannot establish what comes first, but it is interesting to note that a positive change within the muscle and respiration domains was associated with work status for patients with pain in the upper body. However, patients who did not return to work changed more in the movement domain than patients who did return. The sample size in group 1 was small, and such findings warrant further investigation.
Patients with pain localized to the lower body (group 2) had physical findings that improved, even after treatment, resulting in a quicker return to work compared with patients with pain in the upper body. Furthermore, at 18 months, the return-to-work rate was higher in both groups who initially had localized pain compared with those with widespread pain (61% versus 41%), which conforms to previous findings.36,50 As in group 1, patients who later returned to work initially had more physical aberrations, but in group 2 this was found in the movement domain. In patients with localized pain, this finding could indicate a greater potential for change and successful outcome. Similar findings have been reported in a study of patients with low back pain, where people who returned to work initially had longer distances from fingertip to floor than people who did not return to work.51 It must be emphasized, however, that they were not more likely to return to work because they had room for improvement.
Patients with widespread pain (group 3) who later returned to work had fewer physical aberrations at the pretreatment examination, as measured with the GPE-52, mainly within movement domain, compared with patients who remained sick listed. At 6 months, patients who returned to work had still fewer physical aberrations compared with the patients who did not return to work, especially within the movement domain, although not significantly, when we controlled for the pretreatment values. Our findings show that patients with widespread pain had a high degree of physical problems, as measured by the GPE-52, compared with patients with localized pain, and this group had a lower percentage of patients who returned to work, which is in accordance with former studies.31,36,52
The effectiveness of treatment, or lack thereof, was not directly measured in this study. This study also did not focus on details of the treatment program or how the patients adhered to the treatment program, although such adherence could have affected the individual patient's response. The control group participating in the randomized controlled trial from which our study sample was taken34 was not examined with the GPE-52, and it is therefore difficult to infer that the changes seen were related to treatment. The design of this study, however, enables the physical therapist to map magnitude of change in physical findings, both within patients and between the different pain localization groups.32 The selection biases were minimized by the sampling procedure and the design of the randomized study.34 The findings reported in this article, therefore, should have some external validity in relation to domains that may be sensitive and responsive in evaluation of change in patients with long-lasting musculoskeletal pain. Except for sex and age, we did not focus on or control for other factors that may influence change such as education, activity level, cognitive factors, negative health beliefs, pain behavior, and psychosocial factors.5,53,54
Because no study has been performed to demonstrate magnitude of physical change by means of the GPE-52 or similar test batteries, our study can be conceived as a parameter estimation study, which is an important part of the validation process of new instruments.32 However, a test battery showing statistically significant change may not reflect clinically meaningful change. The results in this study suggest that only the respiration and movement domains, and possibly the muscle domain, can be appropriate as outcome measures in intervention studies for patients with long-lasting musculoskeletal pain. For many physical therapists, a barrier might be the time it takes to administer the complete GPE-52. Clinical practice has shown that it takes little time to train for reliable responses in use of the respiration domain and especially the movement domain,24,25 and it takes about 10 minutes to use this part of the instrument. The complete GPE-52, however, could be used as a generic screening battery, because it examines body structures and body function and covers a wide range of musculoskeletal disorders. It helps to answers questions such as: "What degree of physical problems does a patient have, and where do these problems occur?" and "Could the physical findings be possible perpetuating factors that should be addressed in treatment?" Generic scales allow comparisons across different disorders, severities of disorders, interventions, and perhaps even demographic and cultural groups.44
| Conclusion |
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The total GPE-52 score used alone only reflects degree of physical aberration, but it does not indicate where the physical aberration exists. The sum scores in the different domains, however, are much more informative than a total score. A shorter version of this examination instrument might still be adequate in future studies, especially in patients with localized pain. However, if some domains were to be omitted, such as the posture and skin domains, the scale might lose some of its validity because possible aberrations as well as unforeseen effects of an intervention may go undetected.
| Appendix |
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| Footnotes |
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This study was approved by the Regional Ethics Committee and the National Data Inspectorate and was performed according to the Helsinki Declaration.
A poster and abstract of this work were presented at the 10th World Congress on Pain; August 17-22, 2002; San Diego, Calif.
| References |
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