Cultural Differences 1

Running head: CULTURAL DIFFERENCES IN PAIN EXPRESSION

Cultural Differences in Pain Expression in a Cold Pressor Task

Nancy Alvarado

California State Polytechnic University, Pomona

Ralph B. Jester

University of California, Irvine

Christine R. Harris

University of California, San Diego

Julia F. Whitaker

University of Utah, Health Sciences Center

Abstract

Studies have documented the under-treatment of pain in members of ethnic and racial minority groups. This study investigated cultural differences in pain attitudes and physiological responses, self-report, and facial expression during a cold pressor task to investigate possible reasons for undertreatment of pain. Subjects were healthy undergraduates in four subcultures: African American, Hispanic, Asian American and European American. Beyond sex differences, no significant group differences were found in measures of physiological pain. Significant group differences were found in pain attitudes and beliefs and in affective responses, including self report and FACS-coded facial expression. Smiling during pain was more frequent for Hispanic and African American women. Misinterpretation of such cultural differences seems likely to be a partial explanation for under-treatment of minority pain.


Cultural Differences in Pain Expression in a Cold Pressor Task

Numerous studies have documented that members of ethnic and racial minority groups, and women, are more likely to be under-treated for pain (Bonham, 2001; Weisse, Sorum & Dominguez, 2003; Hoffman & Tarzian, 2001). Under-treatment has been reported in emergency treatment of bone fractures (Todd, Deaton, D’Adamo, & Goe, 2000; Todd, Samaroo & Hoffman, 1993), cancer pain (Cleeland, Gonin, Baez, Loehrer & Pandya, 1997; Cleeland, Gonin, Hatfield, Edmonson, Blum, Stewart & Pandya, 1994) and postsurgical care (McDonald, 1994). Further, even when treated, they are less likely to be given stronger opioid drugs (Pletcher, Kertesz, Cohn & Gonzales, 2008). Williams (2002; Kappesser & Williams, 2002; Kappesser, Williams & Prkachin, 2007) suggested that this under-treatment may arise from physician bias, a tendency to underestimate a person’s pain and thus under-prescribe pain medication, or even misdiagnose the underlying condition. Prkachin (Prkachin, Berzins & Mercer, 1994; Prkachin, Mass & Mercer, 2004; Prkachin, Solomon, Hwang & Mercer, 2001) documented a systematic underestimation of pain that was greater among experienced health care providers than untrained observers. In this research, we investigated whether members of racial and ethnic minority groups (here called subcultures) were likely to show differences in their pain expressivity, self-report or physiology that might be misinterpreted by physicians and result in under-treatment for pain.

The tradeoffs between detection of malingering and accurate appraisal of pain may contribute to physician underestimation bias (Williams, 2002). When physicians become too suspicious, their failure to accurately assess pain may contribute to a vicious circle in which chronic pain sufferers exaggerate their pain in order to be adequately treated while physicians respond to the exaggeration by increasingly discounting their expressions of pain. Studies of chronic pain sufferers suggest that individuals may over time exaggerate their expressions in an attempt to more effectively communicate with health care deliverers, even showing pain expressions when no pain is felt (Prkachin, Berzins & Mercer, 1994; Prkachin, 2005). Historically, physicians have been suspicious of higher pain reports. Mendelson and Mendelson (2004) cite Miller and Cartlidge (1974) who defined malingering as not only simulation of disease or disability not present, but also, a much more frequent gross exaggeration of minor disability. Mendelson & Mendelson (2004) stated, “Given the subjective nature of pain, it therefore becomes problematic to determine what would be the “expected” extent of pain associated with a particular physical lesion…” (p. 425). Physicians are reported to become less sympathetic, even angry, if they believe that patients are exaggerating their pain symptoms or reports (Poole & Craig, 1992; Prkachin & Craig, 1995). Keefe & Dunsmore (1992) noted, “Conscious efforts to communicate pain through guarded movements, facial expressions, or extreme ratings of pain upset and even enrage clinicians.” (p. 97, quoted by Prkachin & Craig, 1995, p. 202).

Thus, difficulties can arise for members of minority subcultures if their expression and self report of pain is divergent from that of the majority of patients. Such differences may lead physicians to suspect dissimulation and give rise to discounting of self report or facial expression or even suspicion of malingering. The actual experience of pain among minority group members is not as well studied as among non-minorities but recent investigations suggest that real differences may exist in pain experiences among African Americans; Hispanics, and Asians (Lipton & Marbach, 1984; Edwards & Fillingim, 1999; Breitbart & McDonald, 1996; Sheffield, Biles, Orom, Maixner & Sheps, 2000; Bates, Edwards & Anderson, 1993; Brena, Sanders & Motoyama, 1990; McCracken, Matthews, Tang & Cuba, 2001; Weisenberg, Kreindler, Schacht & Werboff, 1975; Barak, Weisenberg, 1988; Faucett, Gordon & Levine, 1994; Sternbach & Tursky, 1965). To complicate matters, opioid-induced hyperalgesia (a greater sensitivity to pain-inducing experience) may be expected to affect minority group members differentially if their exposure to such drugs differs from that of other groups. Differences in emotional response to clinical situations, including pain-related anxiety, have also been documented in African American patients (Fillingim, Edwards, & Doleys, 2002; McCracken, Matthews, Tang & Cuba, 2001). These studies suggest that increased ratings of pain can result from several sources. Greater awareness of sex differences in pain experience has led to a consequent correction in physician expectations (Weisse, Sorum & Dominguez, 2003). Awareness of cultural differences may lead to a similar correction in physician expectations about minority group pain.

Stereotypes about the expression of pain complicate actual differences in pain expression and report. Early studies of pain expression were often impressionistic rather than scientific because researchers had no method for objectively and systematically describing facial action, as now exists with Ekman and Friesen’s Facial Action Coding System (FACS) (1978). Studies of “Yankee” (Northeastern American) and Jewish subgroups (Tursky & Sternbach, 1967; Sternbach & Tursky, 1965) described Yankees as stoic whereas “Mediterranean” people were described as “dramatic.” Today Asians are stereotypically thought to be more stoic than European-Americans (Chang, 2003).

Whether cultural differences in expression exist or not, wide individual variability implies that an entirely genuine pain response may be inappropriately treated if the physician holds mistaken expectations about the amount of pain a patient should be expressing. To complicate matters, stereotypes differ for males and females due to gender role expectations in some subcultures. For example, Hispanic patients are stereotypically judged as histrionic or overly expressive when female but an expressive Hispanic man may be judged as malingering if his expressions are inconsistent with expectations for male macho stoicism. Or he, himself, may conceal and under-rate his own pain because he considers it unmanly to reveal pain. African-American and Asian stereotypes have historically included insensitivity to pain as part of the justification for mistreatment during enslavement or “Coolie” indentured servitude (Chang, 2003). Such stereotype-driven expectations conflict with the observed greater sensitivity to pain reviewed above. Physician attitudes about malingering or misuse of emergency room services by immigrant groups such as Hispanics and Asians with low socioeconomic status may contribute to resentment and lessened sympathy among physicians. Further, immigrant patients may believe that the way to be a “good patient” is to suffer without complaint, leading to misdiagnosis or under-treatment.

Although physicians routinely deal with pain, they may not be pain experts. Because assessment of pain is generally a holistic judgment with several inputs, physicians may be unaware of the extent to which their own cultural stereotypes and beliefs can affect their interpretation of pain indicators. As Prkachin & Craig (1995) noted, even when beliefs about pain are explicit, “Stereotypes fail to recognize tremendous within-group differences and small between-group differences that call into question their utility.” (p. 198). Thus, understanding the nature of real and assumed differences among groups is crucial to: (a) accurate interpretation of pain self-report and facial expression; and (b) accurate identification of medication-seeking, malingering and other deception. Optimal treatment for members of minority subcultures relies upon accurate estimation of pain whichever indicators are used.

This exploratory research used multiple measures to assess pain expressivity on a cold pressor task across four subcultures within the student population: (1) African Americans; (2) Asian Americans and Asian immigrants; (3) Hispanic; and (4) European Americans. The dependent variables included: (1) autonomic measures; (2) facial expressivity; (3) self report using several types of scales; (4) measurement of pain attitudes by questionnaire; and (5) measurement of acculturation by questionnaire. Our goal was to examine similarities and differences on these measures across the four groups in order to identify any differences that might be linked to stereotypes or the systematic under-treatment by physicians and other health care professionals.

Method

Participants

We recruited university students in order to increase the likelihood of finding healthy subjects without chronic pain or drug use. Participants included: 32 African Americans (17 female, 15 male); 50 Asian Americans (25 female, 25 male), 48 European Americans (22 female, 26 male) and 53 Hispanics (29 female, 24 male). All subjects were students at the ethnically diverse campus of California State Polytechnic University, Pomona, ranging in age from 18 to 53 (mean = 22.1, median = 21, sd = 4.0), with predominantly middle class socioeconomic status (SES) for all four groups. About 12% learned English as a second language, after the age of 6. Subjects were recruited using an online human subjects pool signup system or via flyer and were given course credit or paid $10 for their participation. Subjects were screened for the following self-reported conditions: (1) sores or injury to the hand to be immersed in water; (2) use of medications (such as cold medications or NSAIDs, antidepressants or antipsychotics), and (3) health problems that might interfere with their ability to experience pain or produce facial expressions (including arthritis, heart disease, any circulatory problem, hypertension, liver disease, seizure disorder, diabetes, renal disease, severe asthma, dizzy spells or fainting and cerebrovascular disease). Subjects gave written informed consent and were treated according to ethical guidelines. No subject declined to participate. This study was authorized by the university Institutional Review Board.

Materials

The cold pressor task was administered using a Jeio Tech RW-0525G refrigerated circulating bath which maintained water temperature at 3o Centigrade within two tenths of a degree. A Biopac MP100WS system was used to record heart rate, blood pressure and electrodermal activity. A Vasotrac system was used to continuously measure blood pressure via a wrist cuff. A Sony 900 digital video camera was used to record facial expressivity during a 10 minute baseline and throughout the cold pressor task.

We could find no existing measures of cultural differences in pain attitudes in the literature. Thus, to identify possible cultural differences in pain beliefs and attitudes, a set of standard questions were developed from a thorough reading of the psychology and anthropology literature on pain. These were then presented to four focus groups, asking subjects about their family attitudes and beliefs about pain (Englert, Jester, Alvarado, Harris & Whitaker, 2010). Subjects were recruited in the same manner and from the same pool as for the cold pressor task. Themes and points of difference emerging in the four focus groups were used as the basis for an exploratory pain attitudes questionnaire consisting of 60 questions assessing cultural beliefs about pain and its appropriate expression.

Self-report measures included (1) a series of seven-point scales anchored by emotion terms, (2) the McGill Pain Questionnaire, and (3) a seven-point pain rating scale. Because subjects were not expected to be homogeneous with respect to culture, their acculturation was measured using an inventory appropriate to each subject’s self-described cultural background. For Asian Americans, we presented the SL-ASIA (Suinn, Rickard-Figueroa, Lew, & Vigil, 1987). For Hispanics, we presented the Short Acculturation Scale for Hispanics (Marin, Sabogal, Marin, Otero-Sabogal & Perez-Stable, 1987). For African Americans, we presented the revised African-American Acculturation Scale AAAS-R (Klonoff & Landrine, 2000) and the Black Racial Identity Attitudes Scale (Form RIAS-B) (Helms & Parham, 1990). For European Americans we presented the White Racial Identity Attitudes Scale (Form WRIAS) (Helms & Carter, 1990).

Procedures

Subjects were seated inside a cubicle in a chair facing a screened video camera while an experimenter affixed sensors to monitor heart rate at ankles and wrist, blood pressure and electrodermal activity. The subject was then left alone for a 10 min videorecorded baseline period to permit the subject to become accustomed to the camera and sensors. The experimenter returned and placed a doorbell-type signal in the participant’s right hand, asking the subject to press it, to demonstrate its operation. The subject was instructed to signal at the first sign of pain and again when the pain became intolerable. Subjects were asked to tolerate the water as long as possible, but were also told they could remove the hand whenever they wished. The experimenter left the cubicle and from outside, told the subject to start the task by placing his or her hand in the cold water up to the wrist, with fingers open but not touching the sides or bottom of the tank. The task ended at the second signal or after 3 minutes of immersion. Immediately following the task, the subject was asked to complete the McGill Pain Questionnaire. Following that, the subject was moved to a computer to complete the other pain rating scales and inventories, followed by the pain attitudes questionnaire and then the acculturation questionnaire.

Results

Unless otherwise noted, all analyses used design-appropriate ANOVA and two-tailed t-tests with a significance level of p < .05. Qualitative data was analyzed using the Chi-Square statistic, p < .05.

Cold Threshold and Tolerance

The cold threshold was measured as the time from first immersion in cold water to the time the signal button was pressed for the first time. Cold tolerance was measured as the time from the first button press to signal pain until the second button press to request removal of the hand from the water. A time-out was recorded when the subject left the hand in the water for 3 minutes, at which point the task was ended by the experimenter. No significant differences were found across the four subcultures for threshold, tolerance, or total time in water. However, 12 timeouts were observed in the European American group compared to 6 for Asian American and 4 for the other groups. This contributed to a nearly significant difference in total time in water, F(3,179)=2.126, p=.099, h2 = .03, but did not affect tolerance or threshold. With timeouts removed from all four groups, there was no significant difference in mean pain threshold, tolerance or total time in water across groups. Based on debriefing interviews, the higher number of timeouts among European Americans may have been due to inclusion of a high number of athletes who reported surfing and swimming in cold water or using cold water hydrotherapy to treat sports injuries. A consistent sex difference was found for threshold, t(181)=4.188, p=.000 and total time in water, F(1,155)=7.715, p=.006, h2 = .07, but no significant sex difference was found for tolerance, t(181)=1.265, p=.207.