Ò
PAIN 155 (2014) 439–440
www.elsevier.com/locate/pain
Commentary
Attentional biases in pain: More complex than originally thought? Attentional biases refer to the tendency for people to prioritize information that is of most salience to them. However, attentional biases can be due to facilitated orienting toward a stimulus when first presented (engagement or orienting bias), or due to sustained attention once the stimuli have captured attention (difficulty disengaging). Despite early mixed results, 2 meta-analyses have now demonstrated that chronic pain patients do have attentional biases to pain-related stimuli, at least for sensory pain words [1,9]. Larger effect sizes have been observed at longer latencies using the dot-probe task [9], which are thought to assess sustained attentional processes and on the spatial cuing paradigm, which assesses difficulties disengaging [1]. This pattern of findings has led some authors to suggest that the attentional biases observed in chronic pain samples are most likely accounted for by difficulties in disengaging from pain-related stimuli (eg, [9]). Indeed, in the 2 studies that have been attempted, using the dot-probe paradigm to disambiguate facilitation of processing on congruent trials (engagement biases) vs slowed responding on incongruent trials (disengagement biases), findings of both studies have supported the interpretation that biases are likely to be associated with difficulties disengaging [2,10], with only Haggman and colleagues [2] finding any evidence for engagement biases. The majority of the literature, however, has relied on reaction times to experimental tasks to infer attentional biases, rather than employing more direct methods of assessment, such as eye-tracking methodology. In this issue, Liossi and colleagues [6] use eyetracking methodology to determine (1) whether chronic headache patients show differences in the allocation of attention to painful faces in comparison to healthy controls; and (2) whether this bias is specific to painful faces or generalizes to other emotional contexts (eg, anger and happiness). Their results confirm specific biases in initial orienting toward painful faces (ie, engagement biases) in a group of chronic headache patients compared to healthy controls. Further, Liossi and colleagues [6] failed to find any evidence of difficulty disengaging from painful faces. Rather, they found a nonsignificant trend indicating that headache patients tended to fixate for briefer periods on painful faces, suggestive of a process of subsequent avoidance of painful faces. These results are important because this is the first demonstration in the chronic pain literature that clearly demonstrates biases in the engagement of attention toward painful stimuli in a group of patients experiencing pain. In the only previous study to use eye tracking to examine the attentional biases of patients with chronic pain vs healthy controls, Yang et al. [13] compared 24 patients and 24 controls on their response to a dot-probe task using word stimuli. While they did not find differences between patients with
q
chronic pain and controls, they did find that those patients high in fear of pain were more likely to initially allocate their attention to health catastrophe words. Health catastrophe words reflect words that are associated with a health-related threat, such as paralysis. Further, they also found that patients with chronic pain who were highly fearful of pain engaged in a pattern of early disengagement (avoidance) and subsequent re-engagement with sensory pain words. Hence, there is some concordance between the results of the 2 studies, indicating a pattern of attention biases characterized by early engagement with pain stimuli, which is likely followed by subsequent avoidance (and re-engagement). As Liossi [5] herself argued recently, the demonstration of biases in a cross-sectional sample of patients with chronic pain does not answer the question of whether attentional biases are of theoretical significance in chronic pain. To demonstrate the importance of attentional biases, the literature needs to show either (1) that these biases predict subsequent pain outcomes; and/or (2) that modifying these biases can change subsequent pain outcomes. However, the clear demonstration of initial orienting biases indicates that the assumption that attentional biases are associated with difficulties disengaging from pain stimuli may be incorrect. This finding paves the way for the use of eye-tracking methodologies to investigate the theoretical importance of these attentional processes. To date, a handful of studies have shown that attentional biases are associated with future pain in patients with acute low back pain, cancer patients awaiting surgery, and patients with chest malformations awaiting surgery (eg, [3,4,11]). These studies have highlighted avoidance of negative or affective pain-related stimuli, or excessive engagement with positive stimuli as predictive of worse outcomes. However, none of these studies have assessed early attentional processes. Hence, one explanation for these findings, which are consistent with the emerging eye-tracking literature [6,13], is that a pattern of vigilance-avoidance may be important in the development of chronic pain. While speculative at this juncture, research to clarify these processes is needed, and eye-tracking technology can provide a vehicle to better understand these processes. This is particularly important as there is preliminary research showing that modifying attentional biases can change pain outcomes, both in the laboratory [7] and in clinical samples [8,12]. These paradigms are based on the principal that if patients who are currently experiencing pain demonstrate biases toward painrelated stimuli and we can train patients to attend away from those stimuli, then subsequent pain outcomes will improve. However, if the pattern of attentional biases is shown to be characterized by early engagement biases and subsequent avoidance, then it is likely that these training paradigms are not optimal.
DOI of original article: http://dx.doi.org/10.1016/j.pain.2013.11.014
0304-3959/$36.00 Ó 2013 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.pain.2013.12.020
440
Ò
Commentary / PAIN 155 (2014) 439–440
The use of eye-tracking methodology is essential for understanding these mechanisms, which have been difficult to demonstrate in clinical samples (see [12]). As with most individual studies, the results presented by Liossi and colleagues [6] in this issue of PAINÒ raise more questions than they are able to answer. However, the results clearly indicate the presence of initial biases associated with early attentional engagement. Further, there is some suggestion that these initial biases may be followed by avoidance of these stimuli. While these results need to be replicated and extended, they lay the foundations for a better understanding of attentional processing in pain, which appears to be more complex than originally thought. Conflict of interest
[5] [6]
[7]
[8] [9]
[10]
[11]
The author has no conflicts of interest regarding this manuscript.
[12]
Acknowledgements
[13]
Louise Sharpe is supported by a National Health and Medical Research Council Senior Research Fellowship. References [1] Crombez G, Van Ryckenghem DML, Eccleston C, Van Damme S. Attentional bias to pain-related information: a meta-analysis. PAINÒ 2012;154:497–510. [2] Haggman SP, Sharpe L, Nicholas MK, Refshauge KM. Attentional biases towards sensory pain words in acute and chronic pain patients. J Pain 2010;11:1136–45. [3] Lautenbacher S, Huber C, Baum C, Rossaint R, Hochrein S, Heesen M. Attentional avoidance of negative experiences as predictor of postoperative pain ratings and consumption of analgesics: comparison with other psychological predictors. Pain Med 2011;12:645–53. [4] Lautenbacher S, Huber C, Schofer D, Kunz M, Parthum A, Weber PG, Roman C, Griessinger N, Sitti R. Attentional and emotional mechanisms related to pain as
predictors of chronic postoperative pain: a comparison with other psychological and physiological predictors. PAINÒ 2012;151:722–31. Liossi C. Attentional biases in chronic pain: do they exist and does it really matter? PAINÒ 2012;153:9–10. Liossi C, Schoth DE, Godwin HJ, Liversedge SP. Using eye movements to investigate selective attention in chronic daily headache. PAINÒ 2014;155:503–10. McGowan N, Sharpe L, Refshauge K, Nicholas MK. The effect of attentional retraining and threat expectancy in response to acute pain. PAINÒ 2009;142:101–7. Schoth DE, Georgallis T, Liossi C. Attentional bias modification in people with chronic pain: a proof of concept study. Cogn Behav Ther 2013;42:233–43. Schoth DE, Nunes V, Liossi C. Attentional bias towards pain-related information in chronic pain; a meta-analysis of visual-probe investigations. Clin Psychol Rev 2012;32:13–25. Sharpe L, Dear BF, Schrieber L. Attentional biases in chronic pain associated with rheumatoid arthritis: hypervigilance or difficulty disengaging? J Pain 2009;10:329–35. Sharpe L, Haggman S, Nicholas M, Dear BF, Refshauge K. Avoidance of affective pain stimuli predicts chronicity in patients with acute low back pain. PAINÒ 2014;155:45–52. Sharpe L, Ianello M, Dear BF, Nicholson Perry K, Refshauge K, Nicholas MK. Is there a potential role for attention bias modification in pain patients? Results of 2 randomized, controlled trials. PAINÒ 2012;153:722–31. Yang Z, Jackson T, Chen H. Effects of chronic pain and pain-related fear on orienting and maintenance of attention: an eye movement study. J Pain 2013;14:1148–57.
⇑
Louise Sharpe School of Psychology, Clinical Psychology Unit F12, The University of Sydney, Sydney, NSW 2006, Australia ⇑ Tel.: +61 2 9351 4558; fax: +61 2 9351 7328. E-mail addresses: [email protected], [email protected]
PAIN 155 (2014) 439–440
www.elsevier.com/locate/pain
Commentary
Attentional biases in pain: More complex than originally thought? Attentional biases refer to the tendency for people to prioritize information that is of most salience to them. However, attentional biases can be due to facilitated orienting toward a stimulus when first presented (engagement or orienting bias), or due to sustained attention once the stimuli have captured attention (difficulty disengaging). Despite early mixed results, 2 meta-analyses have now demonstrated that chronic pain patients do have attentional biases to pain-related stimuli, at least for sensory pain words [1,9]. Larger effect sizes have been observed at longer latencies using the dot-probe task [9], which are thought to assess sustained attentional processes and on the spatial cuing paradigm, which assesses difficulties disengaging [1]. This pattern of findings has led some authors to suggest that the attentional biases observed in chronic pain samples are most likely accounted for by difficulties in disengaging from pain-related stimuli (eg, [9]). Indeed, in the 2 studies that have been attempted, using the dot-probe paradigm to disambiguate facilitation of processing on congruent trials (engagement biases) vs slowed responding on incongruent trials (disengagement biases), findings of both studies have supported the interpretation that biases are likely to be associated with difficulties disengaging [2,10], with only Haggman and colleagues [2] finding any evidence for engagement biases. The majority of the literature, however, has relied on reaction times to experimental tasks to infer attentional biases, rather than employing more direct methods of assessment, such as eye-tracking methodology. In this issue, Liossi and colleagues [6] use eyetracking methodology to determine (1) whether chronic headache patients show differences in the allocation of attention to painful faces in comparison to healthy controls; and (2) whether this bias is specific to painful faces or generalizes to other emotional contexts (eg, anger and happiness). Their results confirm specific biases in initial orienting toward painful faces (ie, engagement biases) in a group of chronic headache patients compared to healthy controls. Further, Liossi and colleagues [6] failed to find any evidence of difficulty disengaging from painful faces. Rather, they found a nonsignificant trend indicating that headache patients tended to fixate for briefer periods on painful faces, suggestive of a process of subsequent avoidance of painful faces. These results are important because this is the first demonstration in the chronic pain literature that clearly demonstrates biases in the engagement of attention toward painful stimuli in a group of patients experiencing pain. In the only previous study to use eye tracking to examine the attentional biases of patients with chronic pain vs healthy controls, Yang et al. [13] compared 24 patients and 24 controls on their response to a dot-probe task using word stimuli. While they did not find differences between patients with
q
chronic pain and controls, they did find that those patients high in fear of pain were more likely to initially allocate their attention to health catastrophe words. Health catastrophe words reflect words that are associated with a health-related threat, such as paralysis. Further, they also found that patients with chronic pain who were highly fearful of pain engaged in a pattern of early disengagement (avoidance) and subsequent re-engagement with sensory pain words. Hence, there is some concordance between the results of the 2 studies, indicating a pattern of attention biases characterized by early engagement with pain stimuli, which is likely followed by subsequent avoidance (and re-engagement). As Liossi [5] herself argued recently, the demonstration of biases in a cross-sectional sample of patients with chronic pain does not answer the question of whether attentional biases are of theoretical significance in chronic pain. To demonstrate the importance of attentional biases, the literature needs to show either (1) that these biases predict subsequent pain outcomes; and/or (2) that modifying these biases can change subsequent pain outcomes. However, the clear demonstration of initial orienting biases indicates that the assumption that attentional biases are associated with difficulties disengaging from pain stimuli may be incorrect. This finding paves the way for the use of eye-tracking methodologies to investigate the theoretical importance of these attentional processes. To date, a handful of studies have shown that attentional biases are associated with future pain in patients with acute low back pain, cancer patients awaiting surgery, and patients with chest malformations awaiting surgery (eg, [3,4,11]). These studies have highlighted avoidance of negative or affective pain-related stimuli, or excessive engagement with positive stimuli as predictive of worse outcomes. However, none of these studies have assessed early attentional processes. Hence, one explanation for these findings, which are consistent with the emerging eye-tracking literature [6,13], is that a pattern of vigilance-avoidance may be important in the development of chronic pain. While speculative at this juncture, research to clarify these processes is needed, and eye-tracking technology can provide a vehicle to better understand these processes. This is particularly important as there is preliminary research showing that modifying attentional biases can change pain outcomes, both in the laboratory [7] and in clinical samples [8,12]. These paradigms are based on the principal that if patients who are currently experiencing pain demonstrate biases toward painrelated stimuli and we can train patients to attend away from those stimuli, then subsequent pain outcomes will improve. However, if the pattern of attentional biases is shown to be characterized by early engagement biases and subsequent avoidance, then it is likely that these training paradigms are not optimal.
DOI of original article: http://dx.doi.org/10.1016/j.pain.2013.11.014
0304-3959/$36.00 Ó 2013 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.pain.2013.12.020
440
Ò
Commentary / PAIN 155 (2014) 439–440
The use of eye-tracking methodology is essential for understanding these mechanisms, which have been difficult to demonstrate in clinical samples (see [12]). As with most individual studies, the results presented by Liossi and colleagues [6] in this issue of PAINÒ raise more questions than they are able to answer. However, the results clearly indicate the presence of initial biases associated with early attentional engagement. Further, there is some suggestion that these initial biases may be followed by avoidance of these stimuli. While these results need to be replicated and extended, they lay the foundations for a better understanding of attentional processing in pain, which appears to be more complex than originally thought. Conflict of interest
[5] [6]
[7]
[8] [9]
[10]
[11]
The author has no conflicts of interest regarding this manuscript.
[12]
Acknowledgements
[13]
Louise Sharpe is supported by a National Health and Medical Research Council Senior Research Fellowship. References [1] Crombez G, Van Ryckenghem DML, Eccleston C, Van Damme S. Attentional bias to pain-related information: a meta-analysis. PAINÒ 2012;154:497–510. [2] Haggman SP, Sharpe L, Nicholas MK, Refshauge KM. Attentional biases towards sensory pain words in acute and chronic pain patients. J Pain 2010;11:1136–45. [3] Lautenbacher S, Huber C, Baum C, Rossaint R, Hochrein S, Heesen M. Attentional avoidance of negative experiences as predictor of postoperative pain ratings and consumption of analgesics: comparison with other psychological predictors. Pain Med 2011;12:645–53. [4] Lautenbacher S, Huber C, Schofer D, Kunz M, Parthum A, Weber PG, Roman C, Griessinger N, Sitti R. Attentional and emotional mechanisms related to pain as
predictors of chronic postoperative pain: a comparison with other psychological and physiological predictors. PAINÒ 2012;151:722–31. Liossi C. Attentional biases in chronic pain: do they exist and does it really matter? PAINÒ 2012;153:9–10. Liossi C, Schoth DE, Godwin HJ, Liversedge SP. Using eye movements to investigate selective attention in chronic daily headache. PAINÒ 2014;155:503–10. McGowan N, Sharpe L, Refshauge K, Nicholas MK. The effect of attentional retraining and threat expectancy in response to acute pain. PAINÒ 2009;142:101–7. Schoth DE, Georgallis T, Liossi C. Attentional bias modification in people with chronic pain: a proof of concept study. Cogn Behav Ther 2013;42:233–43. Schoth DE, Nunes V, Liossi C. Attentional bias towards pain-related information in chronic pain; a meta-analysis of visual-probe investigations. Clin Psychol Rev 2012;32:13–25. Sharpe L, Dear BF, Schrieber L. Attentional biases in chronic pain associated with rheumatoid arthritis: hypervigilance or difficulty disengaging? J Pain 2009;10:329–35. Sharpe L, Haggman S, Nicholas M, Dear BF, Refshauge K. Avoidance of affective pain stimuli predicts chronicity in patients with acute low back pain. PAINÒ 2014;155:45–52. Sharpe L, Ianello M, Dear BF, Nicholson Perry K, Refshauge K, Nicholas MK. Is there a potential role for attention bias modification in pain patients? Results of 2 randomized, controlled trials. PAINÒ 2012;153:722–31. Yang Z, Jackson T, Chen H. Effects of chronic pain and pain-related fear on orienting and maintenance of attention: an eye movement study. J Pain 2013;14:1148–57.
⇑
Louise Sharpe School of Psychology, Clinical Psychology Unit F12, The University of Sydney, Sydney, NSW 2006, Australia ⇑ Tel.: +61 2 9351 4558; fax: +61 2 9351 7328. E-mail addresses: [email protected], [email protected]
