ORIGINAL ARTICLE

Translation, Cross-Cultural Adaptation, and Validity of the Korean Version of the Pain Sensitivity Questionnaire in Chronic Pain Patients Ho-Joong Kim, MD*; Ruth Ruscheweyh, MD†; Ji-Hyun Yeo, MD*; Hyeon-Guk Cho, MD*; Je-Min Yi, MD*; Bong-Soon Chang, MD‡; Choon-Ki Lee, MD‡; Jin S. Yeom, MD* *Spine Center and Department of Orthopaedic Surgery, Seoul National University College of Medicine and Seoul National University Bundang Hospital, Sungnam, Korea; †Department of Neurology, University of Munich, Munich, Germany; ‡Department of Orthopaedic Surgery, Seoul National University College of Medicine and Seoul National University Hospital, Seoul, Korea

& Abstract: The purpose of this study was to translate pain sensitivity questionnaires (PSQ) into the Korean language, perform a cross-cultural adaption of the PSQ, and validate the Korean version of PSQ in patients with degenerative spinal disease. The PSQ was translated forward and backward, cross-culturally adapted by 2 independent translators, and approved by an expert committee. The final Korean version of the PSQ was tested on 72 patients with degenerative spinal disease. Test–retest reliability was evaluated for 60 patients (83%) who completed the second assessment in an interval of 4 weeks. The mean PSQ-minor, PSQ-moderate, and PSQ-total (standard deviation [SD]) were 5.40 (2.02), 6.46 (1.98), and 5.93 (1.93), respectively. The PSQ-total, PSQ-minor, and PSQ-moderate of the Korean version showed very good internal consis-

Address correspondence and reprint requests to: Jin S. Yeom, MD, Spine Center and Department of Orthopaedic Surgery, Seoul National University College of Medicine, Seoul National University Bundang Hospital, 166 Gumiro, Bundang-gu, Sungnam, 463-707, Korea. E-mail: [email protected]. Submitted: June 21, 2013; Revision accepted: August 15, 2013 DOI. 10.1111/papr.12123

© 2013 World Institute of Pain, 1530-7085/13/$15.00 Pain Practice, Volume 14, Issue 8, 2014 745–751

tencies determined by the Cronbach’s a of 0.926, 0.869, and 0.877, respectively. For convergent validity, the PSQ scores of the Korean version showed significant correlations with pain catastrophizing scale (PCS) (r = 0.377, P = 0.002; r = 0.365, P = 0.003; r = 0.362, P = 0.003 for PSQ-total, PSQ-minor, and PSQ-moderate of the Korean version, respectively). For test–retest reliability, the intraclass correlation coefficients were 0.782 for PSQ-total, 0.752 for PSQminor, and 0.793 for PSQ-moderate. In conclusion, the validated Korean version of PSQ is a transculturally equivalent, reliable, and valid tool to assess individual pain sensitivity. & Key Words: pain, Korean language, pain intensity, pain sensitivity questionnaire, cross-cultural adaptation

INTRODUCTION It is well known that increased pain perception and sensitivity may constitute a risk factor for the development of chronic pain.1 Previous studies have shown that pain sensitivity is connected with the development of chronic pain disorders such as chronic low back pain,

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tension-type headache, chronic dysfunction of temporomandibular joint, and chronic fibromyalgia.2–4 Another study also suggested that pain sensitivity could be one of the determining factors for symptom severity in degenerative lumbar spinal stenosis.5 Moreover, greater pain sensitivity may also have an influence on the surgical results and outcomes because of differences in pain perception and processing.6,7 The importance of proper assessment of individual pain sensitivity has emerged. Pain sensitivity could possibly influence not only initial symptom severity, but also outcomes of various treatments, from conservative treatment to surgical intervention. Therefore, assessment of pain sensitivity should also be a critical concern for both disease prevention and improved treatment outcomes in groups at high risk of chronic pain.8–10 Hitherto, assessment of individual pain sensitivity mainly depends on experimental pain testing.11 Despite the significance of clinical pain sensitivity assessment, it is hardly being implemented. The reasons for this are requirements of special equipment, staff, time, and associated costs.11,12 Furthermore, subjects do not want painful stimuli by participation in experimental assessment. Recent research demonstrated the valid method for the assessment of individual pain sensitivity.12,13 Ruscheweyh et al. developed the pain sensitivity questionnaire (PSQ), which is composed of 17 items, each describing a daily life situation, asking the subject to rate their pain on a numeric rating scale ranging from 0 (not painful at all) to 10 (worst pain imaginable).12 This has been proven to be a valid assessment system for evaluation of pain sensitivity in both healthy and chronic pain patients.13 However, in order to use this assessment system in non-English-speaking countries, questionnaires have to undergo a standardized process of cross-cultural revalidation in terms of its ability to take into account culture-specific conditions prior to their administration.14 Therefore, the purposes of this study were to translate the PSQ into the Korean language, perform a cross-cultural adaption, and validate the Korean version in patients with chronic pain due to degenerative spinal disease.

plished by following guidelines as described in detail by Beaton et al.14 Translation and Synthesis Two bilingual translators whose mother tongue was Korean independently translated the original English version of PSQ from the study of Ruscheweyh.12 The 2 translators’ versions and the original version were compared and considered by the translators and an orthopedic professor. Thus, both translations were merged and analyzed in detail until consensus was achieved. The backtranslation was performed by 2 independent bilingual English speakers both of whom were professional translators and did not know the purpose of translation. Expert Committee Review All versions of the translation were collected with the original and discussed by an expert committee, which is comprised of the previous 4 translators involved in the process, 2 orthopedic surgeons, and a Korean translation expert. This committee evaluated semantic, idiomatic, experiential, and conceptual equivalence of all items and answers. All elements of the questionnaire were analyzed, and discrepancies between members were discussed until consensus was achieved. The prefinal version of PSQ was created. Test of the Prefinal Version The prefinal version was applied to a group of 30 patients with chronic back pain and leg pain caused by degenerative lumbar disease. After completing the questionnaire, patients were asked for opinions about the structure and content of the questionnaire. A report was then produced after findings were considered by a committee of the original reviewers. The committee approved the prefinal version for further use without any modification. Final Questionnaires

METHODS Study Design and Setting The hospital institutional review board approved this study. The translation and cross-cultural adaptation of the original English version of the PSQ were accom-

The final Korean version of this PSQ was included in a series of questionnaires that also contained a series of other pain-related questions to assess the validity of the Korean-translated version of PSQ. These measures were 0 to 10 VAS (visual analog pain scale) for back pain, 0 to 10 VAS for leg pain, and the previously validated

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Korean version of the pain catastrophizing scale (PCS).15 Patients Seventy-two patients were enrolled. Inclusion criteria included patients of age 50 to 85 years with good comprehension of the Korean language, visiting the outpatient facilities for chronic leg pain and/or back pain caused by degenerative spinal disease without any other musculoskeletal complaints (Table 1). In the present study, patients were considered to have chronic pain when the pain persisted beyond 3 months and for more than 14 days during a 1-month period. Fifty-four of the 72 patients had central spinal or lateral recess stenosis without spondylolisthesis, and 18 had grade I degenerative spondylolisthesis, combined with spinal stenosis in lumbar spine. According to Schizas et al.’s classification,16 19 and 28 patients were of grades A and B of canal stenosis, respectively. Grades C and D of canal stenosis were observed in 15 and 10 patients, respectively. When the degree of disk degeneration was graded from T2-weighted images with the Pfirrmann classification,17 grade III, IV, and V degeneration was observed in 32, 25, and 15 patients, respectively. Patients were excluded: if they had a history of psychological disorder or peripheral vascular disease; if they had fibromyalgia; drug/alcohol abuse; stroke; peripheral polyneuropathy; inflammatory CNS disease; if they had history of previous operation; or if there was any concurrent serious medical condition affecting disability and general health status, including uncontrolled diabetes, sepsis, or cancer. Sixty of 72 patients (83%) completed the second assessment in an interval of 4 weeks. During this period, all patients took medications for pain and physical therapy. However, there

were no therapeutic interventions such as an epidural steroid injection and surgery between applications. For patients who were lost to follow-up, a spine research coordinator tried to contact them via a cell phone tracer for the purpose of helping them to keep second application. Nine patients did not follow up due to improved symptoms, 2 patients moved to another region, and 1 patient could not be contacted. Statistical Analysis Test–retest reliability was assessed by comparing replies to the first and second administrations of PSQ. Reliability was analyzed using intraclass correlation coefficient (ICC). In order to estimate internal consistency, Cronbach’s alpha was used. Factor analysis was also performed to determine dimensions of the scale. For convergent validity, Pearson’s correlation was used by comparing the replies of PSQ with the results of validated Korean version of PCS. Floor and ceiling effects were measured as the percent of patients who reported a minimum or maximum score of PSQ-minor, PSQ-moderate, and PSQ-total, respectively. Desired value for both floor and ceiling effects is 0.5 on exactly 1 factor. The item analysis revealed that the Korean version of PSQ demonstrated the pattern similar to an original study by Ruscheweyh.12 Factor 1, which was constituted by the items of PSQ-moderate score (items 1, 2, 4, 8, 15, 16, 17), was rated more painful, on average, than factor 2, which corresponded to the items of PSQ-minor score (items 3, 6, 7, 10, 11, 12, 14) (Figure 1). However, the mean value of each item was higher than in a previous study.12 The Cronbach’s a of the internal consistency of PSQtotal, PSQ-minor, and PSQ-moderate, measuring to what extent items of a scale represent a common underlying variable, was 0.926, 0.869, and 0.877, respectively. The corrected item–total correlation showed the consistent correlation of each questionnaire score with the combined score of all other questionnaires throughout all questions and ranged from 0.581 to 0.779 in PSQ-total (Figure 2).

Figure 1. Factor analysis of the Korean version of PSQ demonstrated 2 factors that corresponded to mild pain and moderate pain situations, respectively. The 14 items of the Korean version of PSQ were ordered by mean values (PSQ; pain sensitivity questionnaires, SD; standard deviation).

Convergent Validity Convergent validity was evaluated by comparing the PSQ scores with the results of PCS, which had been used

Table 2. Factor Analysis. Primary Factors Loaded by Each Item are Bold-Faced Factor Analysis (n = 72) Item Number 1 2 3 4 6 7 8 10 11 12 14 15 16 17

Factor 1

Factor 2

0.735 0.782 0.145 0.510 0.428 0.229 0.767 0.186 0.160 0.482 0.352 0.657 0.547 0.701

0.293 0.218 0.871 0.488 0.586 0.757 0.305 0.793 0.795 0.550 0.529 0.290 0.435 0.446

Figure 2. Internal consistency of PSQ. Numbers indicate each questionnaire of the PSQ. (PSQ; pain sensitivity questionnaires)

for validation in an original study by Ruscheweyh et al.12 Our Korean version of PSQ scores showed significant correlations with the PCS (PSQ-total: r = 0.377, P = 0.002; PSQ-minor: r = 0.365, P = 0.003; PSQ-moderate: r = 0.362, P = 0.003) (Figure 3; Table 3). Test–Retest Reliability In an interval of 4 weeks, test–retest ICC (3,1) (95% confidence interval) was 0.782 (0.506–0.912) for PSQtotal, 0.752 (0.451–0.899) for PSQ-minor, and 0.793 (0.529–0.917) for PSQ-moderate (n = 60). Test–retest

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Figure 3. Correlation between PSQ-total score and PCS. Pearson’s correlation coefficients (r) are given (PSQ; pain sensitivity questionnaires, PCS; pain catastrophizing scale).

Table 3. Convergent Validity. Pearson’s Correlations Coefficient Between PSQ Scores and PCS PSQ-Minor PCS

r 0.365

P value 0.003

PSQ-Moderate r 0.362

P value 0.003

PSQ-moderate (items 1, 2, 4, 8, 15, 16, and 17) were rated as moderately painful scores, while the items of PSQ-minor (items 3, 6, 7, 10, 11, 12, and 14) were rated as causing minor pain scores on average. Interestingly, the scores of all items were higher than in previous studies,12,13 around 4. However, because the present study groups were completely different from those of a previous study, direct comparison of mean values per items between studies is ineffective. Nonetheless, it would be valuable to consider the ethnic disparities in clinical and experimental pain sensitivity.20 A previous study shows that Asians exhibit enhanced pain sensitivity to experimental pain relative to Caucasians.20 The Korean version of PSQ-total, PSQ-minor, and PSQmoderate showed very good internal consistencies, which was determined by the high values of Cronbach’s a (> 0.8) in all scores. These values are similar to those of the original study by Ruscheweyh et al.12 A value higher than 0.7 is considered acceptable for internal consistency analyses.21 All questions demonstrated good correlation.

PSQ-Total r 0.377

P value 0.002

PSQ, pain sensitivity questionnaire; PCS, pain catastrophizing scale; VAS, visual analog pain scale; R, correlation coefficient.

coefficients above 0.7 are generally accepted as sufficient and coefficients above 0.8 are considered as good.12,19

DISCUSSION Translation and Cross-Cultural Adaptation This study aimed at cross-cultural adaptation, reliability, and validity of the Korean version of the PSQ in subjects with chronic pain caused by degenerative spinal disease. The Korean version of PSQ seemed to be both easily understood and easily administered to the patients. The structure of the original PSQ was not changed, and all questions were maintained in the Korean version of PSQ. Therefore, the present results demonstrate this version to be a reliable, easy-tounderstand, and valid instrument for measuring generalized pain sensitivity in Korean people with degenerative lumbar disease. Further, its reliability was similar to that of the original version by Ruscheweyh et al.12,13 Item Analysis and Internal Consistency The item analysis of the Korean version of PSQ showed results similar to the original version of PSQ.12 Items of

Convergent Validity Our analysis of convergent validity of the Korean version of PSQ revealed satisfactory correlation with previously validated PCS. The correlation coefficients of the Korean version of PSQ with the PCS showed values higher than 0.3, and all were statistically significant. These values were similar to those in a previous study by Ruscheweyh et al., where the original version of PSQ had a significant correlation with the pain-specific measure PCS and nonsignificant correlations with the non-pain-specific measures of depression and anxiety.12 Therefore, these results show that the Korean version of PSQ correlates well with previously established tests measuring similar concepts. Test–Retest Reliability In this study, 60 patients completed questionnaires twice in an interval of 4 weeks. Compared to the original version of PSQ,12 the ICC (3,1) of PSQ scores were lower in the present study. This is likely to be due to longer interval than that in the previous study.12 The longer interval is related to deterioration of correlation coefficients.18 In addition, it could also be due to the fact that patients with chronic pain caused by degenerative lumbar disease (not healthy controls) were studied. Indeed, PSQ test–retest reliability assessed in chronic pain patients over a 4-week interval was very similar to

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that found in the present study (ICC 0.72 for the PSQtotal and 0.71 for the PSQ-minor).13

PSQ-TOTAL SCORES VS. PSQ SUBSCORES Previous results with the PSQ suggest that the PSQ-minor score is equivalent or even slightly superior to the PSQtotal score and significantly superior to the PSQ-moderate score for the prediction of experimental pain sensitivity.5,12,13 In the present study, no clear superiority emerges for any of the 3 scores (PSQ-total, PSQ-minor, and PSQmoderate) regarding their correlations with PCS. This means that all 3 scores are necessary to be collected and may not be cut down to only PSQ subscores or PSQ-total. This study has some limitations. First, the present study included patients with degenerative lumbar disease and did not include normal or healthy subjects. For this reason, the present study could not detect normal PSQ scores in Korean population, ROC curves, and cutoff points. However, given that the original version of PSQ also showed the validity of the PSQ for the assessment of pain perception in chronic pain patients,13 the present study would provide evidence for the reliability and validity of the Korean version of PSQ. Second, the current study should have included younger patients for the analysis. However, this was not feasible because degenerative spinal disease is a prevalent condition only in the elderly. Third, even though a simple forward–backward English translation of PSQ has been made, the original version is in the German language. Therefore, the translation should have been made from the original German version to the Korean version. This would make better the quality of the present results in terms of content validity.

CONCLUSION The current study highlights that the validated Korean version of PSQ is a transculturally equivalent, reliable, and valid tool to assess individual pain sensitivity. Even though the present study consisted of patients with degenerative lumbar disease, this Korean version of the PSQ can be utilized for future clinical studies and treatments in Korea.

ACKNOWLEDGEMENTS We thank and acknowledge Ms. Min-Ji Lee, a spine research coordinator at our institution, for her contributions to the project.

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Translation, cross-cultural adaptation, and validity of the Korean version of the pain sensitivity questionnaire in chronic pain patients.

The purpose of this study was to translate pain sensitivity questionnaires (PSQ) into the Korean language, perform a cross-cultural adaption of the PS...
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