Original Article Development and Validation of a Brazilian Version of the Short-Form McGill Pain Questionnaire (SF-MPQ) ---

-

From the *Multidisciplinary Pain Center, Hospital das Clinicas; † Instituto do Cancer do Estado de Sao Paulo, Sao Paulo, Brazil; ‡School of Nursing, University of Guarulhos (UnG), Guarulhos, Sao Paulo, Brazil; § Department of Neurology, School of Medicine, University of S~ ao Paulo, S~ ao Paulo, Brazil. Address correspondence to Karine Azevedo S~ ao Le~ ao Ferreira, PhD, RN, BSN, R. Anibal Borbola, 105, Parque dos Prıncipes. Sao Paulo, SP, Brazil. Zip Code: 05396-265. E-mail: [email protected] Received March 9, 2011; Revised April 13, 2011; Accepted April 21, 2011. 1524-9042/$36.00 Ó 2013 by the American Society for Pain Management Nursing http://dx.doi.org/10.1016/ j.pmn.2011.04.006

Karine Azevedo S~ ao Le~ ao Ferreira, PhD, RN, BSN,*,†,‡ Daniel Ciampi de Andrade, PhD, MD,*,†,§ and Manoel Jacobsen Teixeira, PhD, MD*,§

ABSTRACT:

The aim of this study was to develop and validate a short form of the Brazilian version of McGill Pain Questionnaire (SF-MPQ). Three hundred two patients with chronic pain filled out the validated Brazilian long form of the McGill Pain Questionnaire (LF-MPQ). Words chosen by $25% of the patients were selected to comprise the SF-MPQ. The Brazilian SF-MPQ consisted of 15 descriptors (8 sensory, 5 affective, and 2 evaluative) rated on a binary mode (present or absent). Four pain scores were derived by counting the words chosen by the patients for sensory, affective, evaluative, and total descriptors. The SF-MPQ showed poor internal consistency (KR-20 ¼ 0.52) but possibly acceptable because it showed discriminant validity to discriminate patients presenting different levels and mechanisms of pain, and it was strongly correlated with the LF-MPQ. The low KR-20 coefficient could result from the small number of items. The Brazilian version of the SF-MPQ proved to be a useful instrument to evaluate the different qualities of pain. It is a reliable option to the long-form MPQ. Ó 2013 by the American Society for Pain Management Nursing

Chronic pain has three main aspects: the sensory-discriminative, affectiveemotional, and cognitive-evaluative. These aspects are present in chronic pain patients in different proportions and may have a negative impact on quality of life. Also, these aspects may respond differently to treatment (Passard, Attal, Benadhira, Brasseur, Saba, Sichere, Perrot, Januel, & Bouhassira, 2007; Picarelli, Teixeira, de Andrade, Myczkowski, Luvisotto, Yeng, Fonoff, Pridmore, & Marcolin, 2010). The assessment of pain is probably one the most challenging areas of health measurement, because pain is an abstract, subjective, and multidimensional experience. Different tools have become available to assess pain in general, such as the Brief Pain Inventory (Ferreira, Teixeira, Mendonza, & Cleeland, 2010), and specific pain syndromes, such as neuropathic pain (Santos, Brito, de Andrade, Kaziyama, Ferreira, Souza, Teixeira, Bouhassira, & Baptista, Pain Management Nursing, Vol 14, No 4 (December), 2013: pp 210-219

Brazilian SF-MPQ

2010). However, despite the large number of pain questionnaires and scales available today, few tools are able to characterize its different aspects. The McGill Pain Questionnaire (MPQ) developed by Melzack (1975) assesses three major dimensions of pain; sensory-discriminative, motivational-affective, and cognitive-evaluative. The first version of the MPQ with 78 descriptors was published (Melzack, 1975). The MPQ was translated into the Brazilian-Portuguese language in 1996 (Pimenta & Teixeira, 1996). The MPQ takes 10 minutes to be filled out, which could be too long for some studies and for many clinical conditions (Melzack, 1975). Therefore, in 1987, a short form of the MPQ was proposed (Melzack, 1987). It consisted of 15 descriptors (11 sensory and 4 affective), one item for assessing the present pain intensity (PPI), and the visual analog scale (VAS). The short form was translated into different languages around the world (Burckhardt & Bjelle, 1994; Dudgeon, Raubertas, & Rosenthal, 1993; Georgoudis, Watson, & Oldham, 2000; Kitisomprayoonkul, Klaphajone, & Kovindha, 2006; Masedo & Esteve, 2000) and became a useful instrument to assess and describe pain in different groups of patients: elderly people (McDonald & Weiskopf, 2001), patients with osteoarthritis (Grafton, Foster, & Wright, 2005), and other pain syndromes (Grace & MacBride-Stewart, 2007). In Brazil, the shortform has not been validated. The aim of the present study was to develop and validate a short-form of the Brazilian version of the MPQ.

METHODS Sample A cross-sectional study at the Multidisciplinary Pain Center, Hospital das Clinicas, School of Medicine, University of S~ao Paulo, in S~ao Paulo, Brazil, was done after receiving approval by the institution’s Ethics Committee. Eligible patients were required to be 1) an outpatient at the institution; 2) diagnosed by a pain specialist as having chronic pain; 3) $18 years old; 4) a native Portuguese speaker; and 5) able to complete the questionnaire. If an eligible patient agreed to participate, a written informed consent was obtained. Data were obtained from patients by an interview performed by a health care provider specialized in pain (physician, nurse, or dentist). A convenience sample of 302 outpatients with chronic pain conditions were enrolled. A power calculation before the study was not done. The sample included patients with each of the following pain conditions: cancer-related (n ¼ 30), low-back

211

pain (n ¼ 30), fibromyalgia (n ¼ 30), postherpetic pain (n ¼ 20), phantom limb pain (n ¼ 10), complex regional pain syndrome (CRPS) (n ¼ 6), myofascial pain (n ¼ 28), visceral/abdominal pain (n ¼ 30), myelopathic syndromes (n ¼ 30), trigeminal neuralgia (n ¼ 30), burning mouth syndrome (n ¼ 28), and work-related pain syndromes (n ¼ 30). They were divided into three groups according to the major pain mechanism: musculoskeletal pain (low-back pain, fibromyalgia, myofascial pain syndrome), neuropathic pain (postherpetic, phantom limb pain, trigeminal neuralgia, burning mouth syndrome, complex regional pain syndrome, myelopathic pain), and other pain syndromes (cancer-related and visceral/abdominal pain). Although some studies strongly suggest that CRPS is not a typical neuropathic pain syndrome (Janig & Baron, 2006) and that fibromyalgia has also an important neuropathic component, in the present study, fibromyalgia was included in the musculoskeletal pain syndrome group and CRPS in the neuropathic pain group, because patients with fibromyalgia would probably describe their pain with words similar to patients with musculoskeletal pain and patients with CRPS would describe their pain similarly to patients in the neuropathic pain group. Development of the Brazilian Version of the Short-Form MPQ The development and validation of the short form of the Brazilian version of the MPQ (BV-SF-MPQ) occurred in two phases: 1) questionnaire development (item generation); and 2) evaluation of psychometric properties. Phase 1: Questionnaire Development—Item Generation. The strategy used to develop the BV-SF-MPQ was similar to that used during the development of the original version of the SF-MPQ (Melzack, 1987). A few representative numbers of words from the sensory, affective, evaluative, and miscellaneous categories of the long form of the McGill Pain Questionnaire (LF-MPQ) were selected and a numeric rating scale was used to provide the overall pain intensity. Patients completed the Brazilian version of the LF-MPQ (BV-LF-MPQ) (Pimenta & Teixeira, 1996). The descriptors chosen by $25% of patients were selected to compose the BV-SF-MPQ. The criterion of 25% was adopted because the descriptors electric-shock and sharp have appeared on the representative word list of some earlier studies with patients with neuropathic pain syndromes (M. Bennett, 2001; M. I. Bennett, Smith, Torrance, & Potter, 2005; Bouhassira, Attal, Alchaar, Boureau, Brochet, Bruxelle, Cunin, Fermanian, Ginies, Grun-Overdyking, JafariSchluep, Lanteri-Minet, Laurent, Mick, Serrie, Valade,

212

Ferreira et al.

& Vicaut, 2005). In the present study, these descriptors were reported by 24.8% and 25.2%, respectively, of the total sample. They did not reach the criterion of 33% adopted by Melzack (1987). In addition, the words sore or aching have been associated with nonneuropathic pain syndromes in other studies (Hoffman et al., 2005; Lin, Kupper, Gammaitoni, Galer, & Jensen, 2011). In the present study, these descriptors were reported by 25.8% and 19.2%, respectively, of the total sample. In Brazilian Portuguese, these words are often used interchangeably. The authors considered that descriptors such as electric-shock, sharp, sore, and aching had to be included in the BV-SF-MPQ, because they have the potential to be of use for discriminating neuropathic from nonneuropathic pain. The resulting questionnaire was pilot tested among patients with chronic pain. They evaluated each word as present or absent. The LF-MPQ includes 78 pain descriptors arranged in three major classes and 20 subclasses, measuring the sensory-discriminative (items 1-10), affective-motivational (items 11-15), and evaluativecognitive (item 16) aspects of pain (Melzack, 1975). There is a class called miscellaneous (items 17-20), that includes items that could not be included in the other three classes (dimensions of pain). Each word from these classes has a rank value indicative of the relative intensity of the descriptor. Different scores can be obtained from the MPQ. The simplest score is the number of words chosen (NWC), which has a range of 0-78, and the rank values of each word are added to obtain a pain rating index (PRI) for each dimension as well as a total score. In the present study, the LF-MPQ was scored according to the NWC as well as rank values of the words selected using the PRIs for the sensory (PRI-S), affective (PRI-A), evaluative (PRI-E), and miscellaneous (PRI-M) groups as well as for the total (PRI-T). In the present study, the LF-MPQ demonstrated internal consistency when measured by the Cronbach alpha coefficient for all 20 subgroups of words (Cronbach alpha ¼ 0.87) and for sensory and affective dimensions (sensory ¼ 0.73; affective ¼ 0.80). The reliability was not good for the miscellaneous class (Cronbach alpha ¼ 0.54). Phase 2: Evaluation of the Psychometric Properties. The validity and reliability of the BV-SF-MPQ were measured according to the definitions and instructions proposed by Nunnaly and Bernstein (1994) and McDowell and Newell (1996). Statistical Analysis Data were stored and analyzed with the use of SPSS 13.0. Descriptive statistics were generated for all variables. The internal consistency reliability of the SF-

MPQ was evaluated by Kuder-Richardson 20 (KR-20) coefficient, because the BV-SF-MPQ questions had dichotomous items (presence or absence). This coefficient was computed for the total items. Spearman correlation coefficients were calculated to assess convergent validity between the BV-SF-MPQ, LF-MPQ, and the numeric rating scale (11 points). Construct validity was determined by known-group validity and discriminant validity. Known-group validity was evaluated by comparing subgroups of patients known to differ in clinical variables with the use of one-way analyses of variance or Kruskal-Wallis tests depending on their adherence to normal distribution. Post hoc contrasts were done with the Bonferroni procedure to control all family alpha levels at .05. We hypothesized that patients with a higher intensity of pain would choose a greater number of words in the SF-MPQ. The patients were classified into three levels of pain intensity, according to the optimal cutoff points on a 0– 10-point numeric rating scale proposed by Serlin, Mendoza, Nakamura, Edwards, and Cleeland, 1995: mild (1-4), moderate (5-6), and severe pain (7-10). A multiple discriminant analysis was performed on the sample to identify which SF-MPQ dimensions contributed significantly to discriminate among different intensity of pain and pain syndromes (neuropathic, musculoskeletal, and other). For all tests, a p value of 25% of the patients (Table 2). Twelve descriptors were selected equally by 25% of the patients presenting both types of pain syndromes. The other six descriptors (flashing, sharp, spreading, exhausting, blinding, and troublesome) were selected by $25% of the patients of either neuropathic or musculoskeletal pain syndromes (Table 2). These 18 descriptors represented the four classes of the LF-MPQ. They were then kept for analysis and were included in the first version of the BV-SF-MPQ, which comprised the following words: sensory (throbbing, jumping, flashing, sharp, pricking, tugging, burning, and sore), affective (tiring, exhausting, sickening, suffocating, blinding, and frightful), evaluative (troublesome and unbearable), and miscellaneous (spreading and nagging).

Brazilian SF-MPQ

TABLE 1. Characteristics of Pain Characteristic Intensity of pain Mild Moderate Severe Pain syndromes Musculoskeletal Neuropathic Other

Present pain intensity LF-MPQ PRI-MPQ PRI-Sensory PRI-Affective PRI-Evaluative NWC-MPQ (total score) NWC-Sensory NWC-Affective NWC-Evaluative SF-MPQ NWC-MPQ (total score) NWC-Sensory NWC-Affective NWC-Evaluative

n

%

22 51 230

7.17 16.73 76.10

118 124 60

39.07 41.06 19.87

Mean

SD

7.66

2.17

28.21 14.72 2.98 5.61 12.39 6.17 3.13 0.92

14.42 7.74 1.62 3.97 5.42 2.85 1.78 0.27

5.82 2.91 2.30 0.60

2.53 1.60 1.20 0.49

PRI ¼ pain rating index (sum of given values of all words chosen); NWC ¼ number of words chosen.

Similar to the procedure used in the development of the English short form of the LF-MPQ, some words were grouped: tiring-exhausting, sharp-pricking, and frightful-blinding. The remaining 15 items were grouped in three pain dimensions: sensory, evaluative, and affective (Table 3). The final version of the SF-MPQ with 15 items was used for the following analyses. In this version, four different scores were calculated: the total score (sum of the rankings of all words chosen); the affective score (sum of the rankings of words chosen in the affective dimension of pain experience); the sensory score (sum of the rankings of words chosen in the sensory dimension); and the evaluative score (sum of the rankings of words chosen in the evaluative dimension). These results are summarized in Table 1. The highest score was obtained in the sensory dimension of pain experience (mean 5.82). Convergent Validity As expected, the sensory, affective, evaluative, and total scores of the short and long forms of the MPQ were significantly correlated. Positive and moderate to

213

strong correlations were obtained among the sensory, affective, and total scores of the short form and the sensory, affective, and total scores of the long form (Table 4). However, the evaluative dimension of both short and long forms was weakly correlated with the other dimensions and the total score. The correlations among numeric rating scale and sensory, evaluative, affective and total scores of the short and long forms were significant, though weak (Table 4). Reliability The reliability of the BV-SF-MPQ was evaluated by the internal consistency. To measure the internal consistency, the KR-20 coefficient of the BV-SF-MPQ with 15 items was performed. The KR-20 coefficient for the total score was 0.52. The low number of items in the questionnaire may partially account for this modest coefficient. Construct Validity The construct validity was measured by the knowngroup validity. It was examined by comparing the sensory, affective, evaluative, and total scores of the short form of the MPQ according to types of pain (pain syndromes) and intensity of pain (mild, moderate, and severe). Except for the evaluative dimension, the scores of the SF-MPQ dimensions differed significantly among subgroups. Patients with severe pain had greater total, sensory, and affective scores than those with moderate or mild pain. These results indicated that SF-MPQ was able to distinguish patients according to their intensity of pain and pain syndrome (Table 5). The construct validity was also examined by multiple discriminant analyses. Results indicated that sensory, affective, and total scores were significantly able to discriminate different intensities of pain (Wilk lambda: sensory ¼ 0.91 [p ¼ .000]; affective ¼ 0.93 [p ¼ .000], and total score ¼ 0.89 [p ¼ .000]); and pain syndromes (Wilk lambda: sensory ¼ 0.97 [p ¼ .037]; affective ¼ 0.91 [p ¼ .000]; and total score ¼ 0.95 [p ¼ .001]).

DISCUSSION Brazilian health care providers have indicated a need for a short instrument that helps to identify sensory, affective, and evaluative descriptors of pain experience. The BV-SF-MPQ proved to be a reliable and simple tool to identify descriptors of pain and to measure pain intensity in patients with neuropathic and musculoskeletal pain conditions. The results of this study showed that sensory, affective, and total scores of BV-SF-MPQ were capable of

214

Ferreira et al.

TABLE 2. Number and Percentage Use of Pain Descriptors by Pain Syndromes Total Sample Pain Descriptor Sensory ~o (flickering) Vibrac¸a Tremor (quivering) Pulsante (pulsing) Latejante (throbbing) Como batida (beating) Como pancada (pounding) Pontada (jumping) Choque (electric-shock) Tiro (shooting) Agulhada (pricking) Perfurante (boring) Facada (drilling) Punhalada (stabbing) Em lanc¸a (lancinating) Fina (sharp) Cortante (cutting) Estrac¸alha (lacerating) ~o (pinching) Belisca Aperto (pressing) Mordida (gnawing)  lica (cramping) Co Esmagamento (crushing) Fisgada (tugging) ~o (pulling) Puxa ~o (wrenching) Em torc¸a Calor (hot) ~o (burning) Queimac¸a Fervente (scalding) Em brasa (searing) Formigamento (tingling) Coceira (itchy) Ardor (smarting) Ferroada (stinging) Mal localizada (dull) Dolorida (sore) Machucada (hurting) Doida (aching) Pesada (heavy) Sensıvel (tender) Esticada (taut) Esfolante (rasping) Rachado (splitting) Evaluative Chata (annoying) Que incomoda (troublesome) Desgastante (miserable) Forte (intense) vel (unbearable) Insuporta Affective Cansativa (tiring) Exaustiva (exhausting) Enjoada (sickening) Sufocante (suffocating) Amedrontadora (fearful)

Neuropathic

Musculoskeletal

Other c2

p Value

n

%

n

%

n

%

n

%

7 7 22 148 6 15 117 75 1 102 18 22 10 5 76 39 36 32 37 7 39 37 104 32 45 48 138 11 20 63 31 68 49 24 78 10 58 72 70 40 11 31

2.3 2.3 7.3 49.0 2.0 5.0 38.7 24.8 0.3 33.8 6.0 7.3 3.3 1.7 25.2 12.9 11.9 10.6 12.3 2.3 12.9 12.3 34.4 10.6 14.9 15.9 45.7 3.6 6.6 20.9 10.3 22.5 16.2 7.9 25.8 3.3 19.2 23.8 23.2 13.2 3.6 10.3

1 1 7 55 — 5 36 37 — 36 4 10 3 2 24 14 8 20 8 4 2 9 35 11 9 17 62 4 9 16 16 34 16 5 28 4 16 30 30 9 2 11

0.8 0.8 5.6 44.4 — 4.0 29.0 29.8 — 29.0 3.2 8.1 2.4 1.6 19.4 11.3 6.5 16.1 6.5 3.2 1.6 7.3 28.2 8.9 7.3 13.7 50.0 3.2 7.3 12.9 12.9 27.4 12.9 4.0 22.6 3.2 12.9 24.2 24.2 7.3 1.6 8.9

5 5 12 61 2 9 54 28 1 45 6 9 3 1 32 14 23 6 24 1 17 24 48 15 23 24 51 6 7 43 9 21 19 12 34 2 25 31 28 21 3 14

4.2 4.2 10.2 51.7 1.7 7.6 45.8 23.7 0.8 38.1 5.1 7.6 2.5 0.8 27.1 11.9 19.5 5.1 20.3 0.8 14.4 20.3 40.7 12.7 19.5 20.3 43.2 5.1 5.9 36.4 7.6 17.8 16.1 10.2 28.8 1.7 21.2 26.3 23.7 17.8 2.5 11.9

1 1 3 32 4 1 27 10 — 21 8 3 4 2 20 11 5 6 5 2 20 4 21 6 13 7 25 1 4 4 6 13 14 7 16 4 17 11 12 10 6 6

1.7 1.7 5.0 53.3 6.7 1.7 45.0 16.7 — 35.0 13.3 5.0 6.7 3.3 33.3 18.3 8.3 10.0 8.3 3.3 33.3 6.7 35.0 10.0 21.7 11.7 41.7 1.7 6.7 6.7 10.0 21.7 23.3 11.7 26.7 6.7 28.3 18.3 20.0 16.7 10.0 10.0

3.28 3.28 2.41 1.86 9.31 3.38 8.38 3.88 1.56 2.29 7.63 0.60 2.64 1.51 4.59 1.97 10.71 7.81 11.92 1.85 36.56 11.79 4.16 0.97 9.84 2.98 1.61 1.42 0.17 29.43 1.83 3.24 3.24 4.53 1.25 3.08 6.69 1.39 0.43 6.61 8.87 0.59

.19 .19 .30 .40 .01* .18 .01* .14 .46 .32 .02* .74 .27 .47 .10 .37 .005* .02* .003* .40 .001* .003* .12 .62 .01* .22 .48 .49 .92 .001* .40 .20 .20 .10 .53 .21 .03* .50 .81 .04* .01* .74

35 92 33 29 89

11.6 30.5 10.9 9.6 29.5

14 45 8 10 33

11.3 36.3 6.5 8.1 26.6

10 34 20 13 33

8.5 28.8 16.9 11.0 28.0

11 13 5 6 23

18.3 21.7 8.3 10.0 38.3

3.79 4.33 7.36 0.62 2.88

.15 .11 .02* .73 .24

145 81 122 92 50

48.0 26.8 40.4 30.5 16.6

47 23 43 32 12

37.9 18.5 34.7 25.8 9.7

61 45 52 43 20

51.7 38.1 44.1 36.4 16.9

37 13 27 17 18

61.7 21.7 45.0 28.3 30.0

10.20 .01* 12.83 .002* 2.87 .24 3.39 .18 12.11 .002* (Continued )

215

Brazilian SF-MPQ

TABLE 2. Continued Total Sample Pain Descriptor Apavorante (frighful) Aterrorizante (terrifying) Castigante (punishing) Atormenta (gruelling) Cruel (cruel) Maldita (vicious) Mortal (killing) vel (wretched) Misera Enlouquecedora (blinding) Miscellaneous Espalha (spreading) Irradia (radiating) Penetra (penetrating) Atravessa (piercing) Aperta (tight) Adormece (numb) Repuxa (drawing) Espreme (squeezing) Rasga (tearing) Fria (cool) Gelada (cold) Congelante (freezing) Aborrecida (nagging) da nausea (nauseating) Agonizante (agonizing) Pavorosa (dreadful) Torturante (torturing)

Neuropathic

Musculoskeletal

Other

n

%

n

%

n

%

n

%

c2

p Value

109 59 40 46 23 30 20 39 88

36.1 19.5 13.2 15.2 7.6 9.9 6.6 12.9 29.1

37 20 10 18 8 8 6 10 29

29.8 16.1 8.1 14.5 6.5 6.5 4.8 8.1 23.4

49 30 24 20 8 15 9 20 40

41.5 25.4 20.3 16.9 6.8 12.7 7.6 16.9 33.9

23 9 6 8 7 7 5 9 19

38.3 15.0 10.0 13.3 11.7 11.7 8.3 15.0 31.7

3.74 4.30 8.61 0.49 1.75 2.90 1.11 4.53 3.48

.15 .12 .01* .78 .42 .23 .57 .10 .18

84 56 31 17 51 52 67 10 16 38 16 5 90 25 19 20 60

27.8 18.5 10.3 5.6 16.9 17.2 22.2 3.3 5.3 12.6 5.3 1.7 29.8 8.3 6.3 6.6 19.9

27 14 15 6 6 27 21 3 5 13 6 — 35 4 5 4 25

21.8 11.3 12.1 4.8 4.8 21.8 16.9 2.4 4.0 10.5 4.8 — 28.2 3.2 4.0 3.2 20.2

41 31 9 10 30 22 32 5 8 19 6 3 39 11 9 9 27

34.7 26.3 7.6 8.5 25.4 18.6 27.1 4.2 6.8 16.1 5.1 2.5 33.1 9.3 7.6 7.6 22.9

16 11 7 1 15 3 14 2 2 6 4 2 16 10 5 7 8

26.7 18.3 11.7 1.7 25.0 5.0 23.3 3.3 3.3 10.0 6.7 3.3 26.7 16.7 8.3 11.7 13.3

5.12 8.98 1.47 3.72 21.76 8.26 3.69 0.62 0.92 2.19 0.29 3.69 1.02 9.89 1.85 4.97 2.30

.08 .01* .48 .16 .001* .02* .16 .73 .63 .33 .87 .16 .60 .01* .39 .08 .32

*Significant difference at the level of p < .05.

discriminating groups of patients with different intensities of pain (mild, moderate, and severe) and different pain syndromes. The BV-SF-MPQ showed convergent validity, because it was highly correlated with the PRI and NWC of the BV-LF-MPQ. Although it did not show good internal consistency when measured by KR-20 coefficient, the BV-SF-MPQ showed results similar to those obtained with the LF-MPQ. Taking these results into account it can be questioned whether the BV-SF-MPQ evaluates the three dimensions of pain (sensory, affective, and evaluative) with equal sensitivity. These data suggest that the sensory and affective dimensions could be well discriminated, but weak evidence was found for the evaluative dimension of pain. It is interesting to notice that similar results were found in the short form of the Spanish LF-MPQ (Masedo & Esteve, 2000). It remains to be evaluated whether these differences are due to the low number of descriptors in the short form for this aspect of chronic pain, or to an intrinsic limitation of the

questionnaire itself to evaluate such complex phenomenon. The criterion adopted to select descriptors to the BV-SF-MPQ was not the same one adopted by Melzack in the development of the original version of the SFMPQ (Melzack, 1987). If the Melzack’s criterion was used (select the descriptors chosen by $33% of patients), only eight descriptors would have been selected (throbbing, jumping, pricking, tugging, burning, tiring, sickening, and frightful). Melzack did not explain the reason he established 33% as a cutoff point for selecting the descriptors. In the Swedish translation, focused on rheumatoid arthritis patients, only eight of the 15 descriptors met the criterion of 33% (Burckhardt & Bjelle, 1994). Also in the validation of the Thai version (Kitisomprayoonkul, Klaphajone, & Kovindha, 2006), three pain descriptors (stabbing, gnawing, and splitting) did not meet the 33% cutoff. Interestingly, a study showed that older people used a number of additional words not usually found in the SF-MPQ to describe their pain (Bergh, Gunnarsson,

216

Ferreira et al.

TABLE 3. The Short-Form McGill Pain Questionnaire (Brazilian Version)* Dimension

Presence

Absence

Sensory 1. Latejante (throbbing) 2. pontada (jumping) 3. choque (flashing) 4. fina-agulhada (sharp-pricking) 5. fisgada (tugging) ~o (burning) 6. queimac¸a 7. espalha (spreading) 8. dolorida/doida (sore/aching)

() () () () () () () ()

() () () () () () () ()

()

()

Affective 9. cansativa-exaustiva (tiringexhausting) 10. enjoada (sickening) 11. sufocante (suffocating) 12. apavorante-enlouquecedora (frightful-blinding) 13. aborrecida (nagging)

() () ()

() () ()

()

()

Evaluative 14. que incomoda (troublesome) vel (unbearable) 15. insuporta

() ()

() ()

Localization of pain

*The actual scale used by the subjects was that the VAS line was 10 cm in length.

Allwood, Oden, Sjostrom, & Steen, 2005), indicating that special populations might require a specific version of the SF-MPQ. BV-SF-MPQ had only six words in common with Melzack’s original SF-MPQ: throbbing, sickening,

sharp, burning, and tiring-exhausting. This could reflect cultural differences between Brazilian and Canadian individuals unrelated to overall pain intensity, because ethnicity was identified as a moderating variable for five items of the SF-MPQ (gnawing, aching,

TABLE 4. Correlation Coefficients Between Brazilian Version of the SF-MPQ Scores, LF-MPQ Scores, and Numeric Pain Rating Scale, r (p Value) Brazilian Version of SF-MPQ Variable LF-MPQ (PRI)* Total score PRI- Sensory PRI- Affective PRI- Evaluative LF-MPQ (NWC) Total score NWC- Sensory NWC- Affective NWC- Evaluative SF-MPQ (NWC) Total score NWC- Sensory NWC- Affective NWC- Evaluative

Total score

Sensory

Evaluative

Affective

Numeric Rating Scale

0.66 (.000) 0.60 (.000) 0.61 (.000) 0.31 (.000)

0.50 (.000) 0.51 (.000) 0.41 (.000) 0.20 (.001)

0.20 (.000) 0.13 (.029) 0.18 (.001) 0.39 (.000)

0.63 (.000) 0.53 (.000) 0.70 (.000) 0.30 (.000)

0.46 (.000) 0.37 (.000) 0.43 (.000) 0.38 (.000)

0.75 (.000) 0.73 (.000) 0.65 (.000) 0.32 (.000)

0.61 (.000) 0.67 (.000) 0.43 (.000) 0.21 (.000)

0.16 (.004) 0.13 (.019) 0.19 (.001) 0.36 (.000)

0.69 (.000) 0.58 (.000) 0.72 (.000) 0.29 (.000)

0.42 (.000) 0.37 (.000) 0.38 (.000) 0.20 (.001)

1.00 — — —

0.90 (.000) 1.00 0.50 (.000) 0.10 (.078)

0.31 (.000) 0.10 (.078) 0.12 (.033) 1.00

0.78 (.000) 0.47 (.000) 1.00 0.12 (.033)

0.31 (.000) 0.21 (.000) 0.28 (.001) 0.19 (.002)

PRI ¼ pain rating index (sum of given values of all words chosen); NWC ¼ number of words chosen.

217

Brazilian SF-MPQ

TABLE 5. Comparison of the Mean Number of Words Chosen in the Brazilian Version of the Short-Form McGill Pain Questionnaire (SF-MPQ) According to Pain Syndromes and Intensity of Pain Pain Syndrome Total Sample

Neuropathic (N)

Mean

SD

Mean

SD

Mean

SD

Mean

Total score

5.82

2.53

5.17

2.77

6.41

2.31

6.00

Sensory dimension

2.91

1.60

2.65

1.52

3.17

1.65

2.97

Affective dimension

2.30

1.20

1.90

1.41

2.67

1.00

2.43

Evaluative dimension

0.60

0.49

0.63

0.49

0.57

0.50

0.60

SF-MPQ

Musculoskeletal (M)

Other (O) SD

Test

p Value, Post Hoc Contrasts

7.767† .001*, N < M p ¼ .000, N < O p ¼ .002 1.64 6.16‡ .037*, N < M p ¼ .033, N < O p ¼ .002 0.77 20.01‡ .001*, N < M p ¼ .000, N < O p ¼ .001 0.49 0.94‡ .62 2.11

Level of Pain Intensity Mild

Moderate

Severe

Mean

SD

Mean

SD

Mean

SD

Total score





3.22

2.18

5.05

2.64

6.22

2.40

15.04†

Sensory dimension





1.50

1.20

2.55

1.66

3.18

1.54

7.86‡

Affective dimension Evaluative dimension





1.33

1.41

1.98

1.35

2.44

1.10

14.51‡





0.39

0.50

0.52

0.51

0.60

0.49

3.55‡

.01*, mild < moderate p ¼ .024, mild

Development and validation of a Brazilian version of the short-form McGill pain questionnaire (SF-MPQ).

The aim of this study was to develop and validate a short form of the Brazilian version of McGill Pain Questionnaire (SF-MPQ). Three hundred two patie...
315KB Sizes 0 Downloads 0 Views