1
|
Pavy F, Zaman J, Van den Noortgate W, Scarpa A, von Leupoldt A, Torta DM. The effect of unpredictability on the perception of pain: a systematic review and meta-analysis. Pain 2024; 165:1702-1718. [PMID: 38422488 DOI: 10.1097/j.pain.0000000000003199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 01/11/2024] [Indexed: 03/02/2024]
Abstract
ABSTRACT Despite being widely assumed, the worsening impact of unpredictability on pain perception remains unclear because of conflicting empirical evidence, and a lack of systematic integration of past research findings. To fill this gap, we conducted a systematic review and meta-analysis focusing on the effect of unpredictability on pain perception. We also conducted meta-regression analyses to examine the moderating effect of several moderators associated with pain and unpredictability: stimulus duration, calibrated stimulus pain intensity, pain intensity expectation, controllability, anticipation delay, state and trait negative affectivity, sex/gender and age of the participants, type of unpredictability (intensity, onset, duration, location), and method of pain induction (thermal, electrical, mechanical pressure, mechanical distention). We included 73 experimental studies with adult volunteers manipulating the (un)predictability of painful stimuli and measuring perceived pain intensity and pain unpleasantness in predictable and unpredictable contexts. Because there are insufficient studies with patients, we focused on healthy volunteers. Our results did not reveal any effect of unpredictability on pain perception. However, several significant moderators were found, ie, targeted stimulus pain intensity, expected pain intensity, and state negative affectivity. Trait negative affectivity and uncontrollability showed no significant effect, presumably because of the low number of included studies. Thus, further investigation is necessary to clearly determine their role in unpredictable pain perception.
Collapse
Affiliation(s)
- Fabien Pavy
- Research Group Health Psychology, Faculty of Psychology and Educational Sciences, KU Leuven, Belgium
| | - Jonas Zaman
- Research Group Health Psychology, Faculty of Psychology and Educational Sciences, KU Leuven, Belgium
- Centre for the Psychology of Learning and Experimental Psychopathology, Faculty of Psychology and Educational Sciences, KU Leuven, Belgium
- School of Social Sciences, Hasselt University, Hasselt, Belgium
| | - Wim Van den Noortgate
- Methodology of Educational Sciences, Faculty of Psychology and Educational Sciences, & Itec, an Imec Research Group, KU Leuven, Belgium
| | - Aurelia Scarpa
- Research Group Health Psychology, Faculty of Psychology and Educational Sciences, KU Leuven, Belgium
| | - Andreas von Leupoldt
- Research Group Health Psychology, Faculty of Psychology and Educational Sciences, KU Leuven, Belgium
| | - Diana M Torta
- Research Group Health Psychology, Faculty of Psychology and Educational Sciences, KU Leuven, Belgium
| |
Collapse
|
2
|
Sean M, Coulombe-Lévêque A, Nadeau W, Charest AC, Martel M, Léonard G, Tétreault P. Counting your chickens before they hatch: improvements in an untreated chronic pain population, beyond regression to the mean and the placebo effect. Pain Rep 2024; 9:e1157. [PMID: 38689593 PMCID: PMC11057814 DOI: 10.1097/pr9.0000000000001157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 01/22/2024] [Accepted: 02/20/2024] [Indexed: 05/02/2024] Open
Abstract
Introduction Isolating the effect of an intervention from the natural course and fluctuations of a condition is a challenge in any clinical trial, particularly in the field of pain. Regression to the mean (RTM) may explain some of these observed fluctuations. Objectives In this paper, we describe and quantify the natural trajectory of questionnaire scores over time, based on initial scores. Methods Twenty-seven untreated chronic low back pain patients and 25 healthy controls took part in this observational study, wherein they were asked to complete an array of questionnaires commonly used in pain studies during each of 3 visits (V1, V2, V3) at the 2-month interval. Scores at V1 were classified into 3 subgroups (extremely high, normal, and extremely low), based on z-scores. The average delta (∆ = V2 - V1) was calculated for each subgroup, for each questionnaire, to describe the evolution of scores over time based on initial scores. This analysis was repeated with the data for V2 and V3. Results Our results show that high initial scores were widely followed by more average scores, while low initial scores tended to be followed by similar (low) scores. Conclusion These trajectories cannot be attributable to RTM alone because of their asymmetry, nor to the placebo effect as they occurred in the absence of any intervention. However, they could be the result of an Effect of Care, wherein participants had meaningful improvements simply from taking part in a study. The improvement observed in patients with high initial scores should be carefully taken into account when interpreting results from clinical trials.
Collapse
Affiliation(s)
- Monica Sean
- Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
- Department of Anesthesiology, Sherbrooke, QC, Canada
- Centre de Recherche du CHUS, Sherbrooke, QC, Canada
| | - Alexia Coulombe-Lévêque
- Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
- School of Rehabilitation, Sherbrooke, QC, Canada
- Research Centre on Aging, Sherbrooke, QC, Canada
| | - William Nadeau
- Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Anne-Catherine Charest
- Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Marylie Martel
- Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
- Centre de Recherche du CHUS, Sherbrooke, QC, Canada
| | - Guillaume Léonard
- Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
- School of Rehabilitation, Sherbrooke, QC, Canada
- Research Centre on Aging, Sherbrooke, QC, Canada
| | - Pascal Tétreault
- Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
- Department of Anesthesiology, Sherbrooke, QC, Canada
- Centre de Recherche du CHUS, Sherbrooke, QC, Canada
- Department of Nuclear Medicine and Radiobiology, Sherbrooke, QC, Canada
| |
Collapse
|
3
|
Li CN, Keay KA, Henderson LA, Mychasiuk R. Re-examining the Mysterious Role of the Cerebellum in Pain. J Neurosci 2024; 44:e1538232024. [PMID: 38658164 PMCID: PMC11044115 DOI: 10.1523/jneurosci.1538-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Revised: 03/06/2024] [Accepted: 03/06/2024] [Indexed: 04/26/2024] Open
Abstract
Pain is considered a multidimensional experience that embodies not merely sensation, but also emotion and perception. As is appropriate for this complexity, pain is represented and processed by an extensive matrix of cortical and subcortical structures. Of these structures, the cerebellum is gaining increasing attention. Although association between the cerebellum and both acute and chronic pain have been extensively detailed in electrophysiological and neuroimaging studies, a deep understanding of what functions are mediated by these associations is lacking. Nevertheless, the available evidence implies that lobules IV-VI and Crus I are especially pertinent to pain processing, and anatomical studies reveal that these regions connect with higher-order structures of sensorimotor, emotional, and cognitive function. Therefore, we speculate that the cerebellum exerts a modulatory role in pain via its communication with sites of sensorimotor, executive, reward, and limbic function. On this basis, in this review, we propose numerous ways in which the cerebellum might contribute to both acute and chronic pain, drawing particular attention to emotional and cognitive elements of pain. In addition, we emphasise the importance of advancing our knowledge about the relationship between the cerebellum and pain by discussing novel therapeutic opportunities that capitalize on this association.
Collapse
Affiliation(s)
- Crystal N Li
- Department of Neuroscience, School of Translational Medicine, Monash University, Melbourne, VIC 3004, Australia
| | - Kevin A Keay
- School of Medical Sciences (Neuroscience) and Brain and Mind Centre, University of Sydney, NSW 2006, Australia
| | - Luke A Henderson
- School of Medical Sciences (Neuroscience) and Brain and Mind Centre, University of Sydney, NSW 2006, Australia
| | - Richelle Mychasiuk
- Department of Neuroscience, School of Translational Medicine, Monash University, Melbourne, VIC 3004, Australia
| |
Collapse
|
4
|
Crawford LS, Mills EP, Peek A, Macefield VG, Keay KA, Henderson LA. Function and biochemistry of the dorsolateral prefrontal cortex during placebo analgesia: how the certainty of prior experiences shapes endogenous pain relief. Cereb Cortex 2023; 33:9822-9834. [PMID: 37415068 PMCID: PMC10472490 DOI: 10.1093/cercor/bhad247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 06/15/2023] [Accepted: 06/17/2023] [Indexed: 07/08/2023] Open
Abstract
Prior experiences, conditioning cues, and expectations of improvement are essential for placebo analgesia expression. The dorsolateral prefrontal cortex is considered a key region for converting these factors into placebo responses. Since dorsolateral prefrontal cortex neuromodulation can attenuate or amplify placebo, we sought to investigate dorsolateral prefrontal cortex biochemistry and function in 38 healthy individuals during placebo analgesia. After conditioning participants to expect pain relief from a placebo "lidocaine" cream, we collected baseline magnetic resonance spectroscopy (1H-MRS) at 7 Tesla over the right dorsolateral prefrontal cortex. Following this, functional magnetic resonance imaging scans were collected during which identical noxious heat stimuli were delivered to the control and placebo-treated forearm sites. There was no significant difference in the concentration of gamma-aminobutyric acid, glutamate, Myo-inositol, or N-acetylaspartate at the level of the right dorsolateral prefrontal cortex between placebo responders and nonresponders. However, we identified a significant inverse relationship between the excitatory neurotransmitter glutamate and pain rating variability during conditioning. Moreover, we found placebo-related activation within the right dorsolateral prefrontal cortex and altered functional magnetic resonance imaging coupling between the dorsolateral prefrontal cortex and the midbrain periaqueductal gray, which also correlated with dorsolateral prefrontal cortex glutamate. These data suggest that the dorsolateral prefrontal cortex formulates stimulus-response relationships during conditioning, which are then translated to altered cortico-brainstem functional relationships and placebo analgesia expression.
Collapse
Affiliation(s)
- Lewis S Crawford
- School of Medical Sciences (Neuroscience), Brain and Mind Centre, University of Sydney, Sydney 2006, Australia
| | - Emily P Mills
- School of Medical Sciences (Neuroscience), Brain and Mind Centre, University of Sydney, Sydney 2006, Australia
| | - A Peek
- School of Medical Sciences (Neuroscience), Brain and Mind Centre, University of Sydney, Sydney 2006, Australia
| | | | - Kevin A Keay
- School of Medical Sciences (Neuroscience), Brain and Mind Centre, University of Sydney, Sydney 2006, Australia
| | - Luke A Henderson
- School of Medical Sciences (Neuroscience), Brain and Mind Centre, University of Sydney, Sydney 2006, Australia
| |
Collapse
|
5
|
Cha M, Eum YJ, Kim K, Kim L, Bak H, Sohn JH, Cheong C, Lee BH. Diffusion tensor imaging reveals sex differences in pain sensitivity of rats. Front Mol Neurosci 2023; 16:1073963. [PMID: 36937048 PMCID: PMC10017469 DOI: 10.3389/fnmol.2023.1073963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 02/06/2023] [Indexed: 03/06/2023] Open
Abstract
Studies on differences in brain structure and function according to sex are reported to contribute to differences in behavior and cognition. However, few studies have investigated brain structures or used tractography to investigate gender differences in pain sensitivity. The identification of tracts involved in sex-based structural differences that show pain sensitivity has remained elusive to date. Here, we attempted to demonstrate the sex differences in pain sensitivity and to clarify its relationship with brain structural connectivity. In this study, pain behavior test and brain diffusion tensor imaging (DTI) were performed in male and female rats and tractography was performed on the whole brain using fiber tracking software. We selected eight brain regions related to pain and performed a tractography analysis of these regions. Fractional anisotropy (FA) measurements using automated tractography revealed sex differences in the anterior cingulate cortex (ACC)-, prefrontal cortex (PFC)-, and ventral posterior thalamus-related brain connections. In addition, the results of the correlation analysis of pain sensitivity and DTI tractography showed differences in mean, axial, and radial diffusivities, as well as FA. This study revealed the potential of DTI for exploring circuits involved in pain sensitivity. The behavioral and functional relevance's of measures derived from DTI tractography is demonstrated by their relationship with pain sensitivity.
Collapse
Affiliation(s)
- Myeounghoon Cha
- Department of Physiology, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Young-Ji Eum
- Bio-Chemical Analysis Team, Korea Basic Science Institute, Cheongju, Republic of Korea
| | - Kyeongmin Kim
- Department of Physiology, Yonsei University College of Medicine, Seoul, Republic of Korea
- Graduate School of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Leejeong Kim
- Department of Physiology, Yonsei University College of Medicine, Seoul, Republic of Korea
- Graduate School of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Hyeji Bak
- Department of Physiology, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Jin-Hun Sohn
- Department of Physiology, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Chaejoon Cheong
- Bio-Chemical Analysis Team, Korea Basic Science Institute, Cheongju, Republic of Korea
- *Correspondence: Chaejoon Cheong,
| | - Bae Hwan Lee
- Department of Physiology, Yonsei University College of Medicine, Seoul, Republic of Korea
- Graduate School of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul, Republic of Korea
- Bae Hwan Lee,
| |
Collapse
|
6
|
Barjola P, Peláez I, Ferrera D, González-Gutiérrez JL, Velasco L, Peñacoba-Puente C, López-López A, Fernandes-Magalhaes R, Mercado F. Electrophysiological indices of pain expectation abnormalities in fibromyalgia patients. Front Hum Neurosci 2022; 16:943976. [PMID: 36248693 PMCID: PMC9562711 DOI: 10.3389/fnhum.2022.943976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Accepted: 09/12/2022] [Indexed: 11/13/2022] Open
Abstract
Fibromyalgia is a chronic pain syndrome characterized by dysfunctional processing of nociceptive stimulation. Neuroimaging studies have pointed out that pain-related network functioning seems to be altered in these patients. It is thought that this clinical symptomatology may be maintained or even strengthened because of an enhanced expectancy for painful stimuli or its forthcoming appearance. However, neural electrophysiological correlates associated with such attentional mechanisms have been scarcely explored. In the current study, expectancy processes of upcoming laser stimulation (painful and non-painful) and its further processing were explored by event-related potentials (ERPs). Nineteen fibromyalgia patients and twenty healthy control volunteers took part in the experiment. Behavioral measures (reaction times and subjective pain perception) were also collected. We manipulated the pain/no pain expectancy through an S1–S2 paradigm (cue-target). S1 (image: triangle or square) predicted the S2 appearance (laser stimulation: warmth or pinprick sensation). Laser stimuli were delivered using a CO2 laser device. Temporal and spatial principal component analyses were employed to define and quantify the ERP component reliability. Statistical analyses revealed the existence of an abnormal pattern of pain expectancy in patients with fibromyalgia. Specifically, our results showed attenuated amplitudes at posterior lCNV component in anticipation of painful stimulation that was not found in healthy participants. In contrast, although larger P2 amplitudes to painful compared to innocuous events were shown, patients did not show any amplitude change in this laser-evoked response as a function of pain predictive cues (as occurred in the healthy control group). Additionally, analyses of the subjective perception of pain and reaction time indicated that laser stimuli preceded by pain cues were rated as more painful than those signaling non-pain expectancy and were associated with faster responses. Differences between groups were not found. The present findings suggest the presence of dysfunction in pain expectation mechanisms in fibromyalgia that eventually may make it difficult for patients to correctly interpret signs that prevent pain symptoms. Furthermore, the abnormal pattern in pain expectancy displayed by fibromyalgia patients could result in ineffective pain coping strategies. Understanding the neural correlates of pain processing and its modulatory factors is crucial to identify treatments for chronic pain syndromes.
Collapse
|
7
|
Pain is Not a "thing": How That Error Affects Language and Logic in Pain Medicine. THE JOURNAL OF PAIN 2022; 23:1283-1293. [PMID: 35427806 DOI: 10.1016/j.jpain.2022.03.235] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 03/08/2022] [Accepted: 03/17/2022] [Indexed: 02/06/2023]
Abstract
Effectiveness in academic and clinical communication depends upon agreement on what words and concepts denote and on the consequent ability to argue logically and accurately. In the pain medicine literature there are many examples of imprecision and confusion in this respect, including misnomers and fallacies in reasoning. This article firstly critically examines some of these misnomers. Identified themes include pain being conceptualised as a "thing," conflation between nociception and pain, and confusion between stimulus and response and between the perspectives of the experiencer and the observer of "pain." Secondly, fallacies in reasoning are identified that contribute to imprecision and confusion. These include reification of pain, attributing to the brain functions that belong to whole organisms, and the illusory truth effect. Thirdly, these themes are identified also in constructs that are shown to be based more on speculation than on fact. Taken together, these observations reveal a need to review and, where necessary, modify terminology and concepts used in Pain Medicine. PERSPECTIVE: This article examines a number of words and constructs commonly found in the pain literature from the perspective of accuracy in terms of their consistency of usage, concordance with fact, degree of speculation and logical argument. A common major theme is the error of considering pain as a "thing" that has agentive properties. A need to clarify much of the language used in Pain Medicine is identified.
Collapse
|
8
|
Abstract
PURPOSE OF REVIEW In this review, we illustrate and discuss the recent findings regarding the epidemiology and pathophysiology of migraine triggers and their implications in clinical practice. RECENT FINDINGS Data from the literature suggest that individual triggers fail to provoke migraine attack in experimental settings. It is therefore possible that more triggers acting in combination are needed to induce an attack by promoting some degree of brain dysfunction and thus increasing the vulnerability to migraine. Caution is however needed, because some of the factors rated as triggers by the patients may actually be a component of the clinical picture of migraine attacks. SUMMARY Trigger factors of migraine are endogenous or exogenous elements associated with an increased likelihood of an attack in a short period of time and are reported by up to 75.9% of patients. Triggers must be differentiated from premonitory symptoms that precede the headache phase but do not have a causative role in attack provocation, being rather the very first manifestations of the attack. Identification of real triggers is an important step in the management of migraine. Vice versa, promoting an active avoiding behaviour toward factors whose role as triggers is not certain would be ineffective and even frustrating for patients.
Collapse
|
9
|
Temporal–spectral signaling of sensory information and expectations in the cerebral processing of pain. Proc Natl Acad Sci U S A 2022; 119:2116616119. [PMID: 34983852 PMCID: PMC8740684 DOI: 10.1073/pnas.2116616119] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/22/2021] [Indexed: 01/14/2023] Open
Abstract
Pain is not only shaped by sensory information but also by an individual’s expectations. Here, we investigated how commonly analyzed electroencephalography (EEG) responses to pain signal sensory information, expectations, and discrepancies thereof (prediction errors) in the processing of pain. Bayesian analysis confirmed that pain perception was shaped by objective sensory information and expectations. In contrast, EEG responses at different latencies (including the N1, N2, and P2 components) and frequencies (including alpha, beta, and gamma oscillations) were shaped by sensory information but not by expectations. Thus, EEG responses to pain are more involved in signaling sensory information than in signaling expectations or prediction errors. Expectation effects are obviously mediated by other brain mechanisms than the effects of sensory information on pain. The perception of pain is shaped by somatosensory information about threat. However, pain is also influenced by an individual’s expectations. Such expectations can result in clinically relevant modulations and abnormalities of pain. In the brain, sensory information, expectations (predictions), and discrepancies thereof (prediction errors) are signaled by an extended network of brain areas which generate evoked potentials and oscillatory responses at different latencies and frequencies. However, a comprehensive picture of how evoked and oscillatory brain responses signal sensory information, predictions, and prediction errors in the processing of pain is lacking so far. Here, we therefore applied brief painful stimuli to 48 healthy human participants and independently modulated sensory information (stimulus intensity) and expectations of pain intensity while measuring brain activity using electroencephalography (EEG). Pain ratings confirmed that pain intensity was shaped by both sensory information and expectations. In contrast, Bayesian analyses revealed that stimulus-induced EEG responses at different latencies (the N1, N2, and P2 components) and frequencies (alpha, beta, and gamma oscillations) were shaped by sensory information but not by expectations. Expectations, however, shaped alpha and beta oscillations before the painful stimuli. These findings indicate that commonly analyzed EEG responses to painful stimuli are more involved in signaling sensory information than in signaling expectations or mismatches of sensory information and expectations. Moreover, they indicate that the effects of expectations on pain are served by brain mechanisms which differ from those conveying effects of sensory information on pain.
Collapse
|
10
|
Brainstem Mechanisms of Pain Modulation: A within-Subjects 7T fMRI Study of Placebo Analgesic and Nocebo Hyperalgesic Responses. J Neurosci 2021; 41:9794-9806. [PMID: 34697093 DOI: 10.1523/jneurosci.0806-21.2021] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 09/23/2021] [Accepted: 09/28/2021] [Indexed: 11/21/2022] Open
Abstract
Pain perception can be powerfully influenced by an individual's expectations and beliefs. Although the cortical circuitry responsible for pain modulation has been thoroughly investigated, the brainstem pathways involved in the modulatory phenomena of placebo analgesia and nocebo hyperalgesia remain to be directly addressed. This study used ultra-high-field 7 tesla functional MRI (fMRI) to accurately resolve differences in brainstem circuitry present during the generation of placebo analgesia and nocebo hyperalgesia in healthy human participants (N = 25, 12 male). Over 2 successive days, through blinded application of altered thermal stimuli, participants were deceptively conditioned to believe that two inert creams labeled lidocaine (placebo) and capsaicin (nocebo) were acting to modulate their pain relative to a third Vaseline (control) cream. In a subsequent test phase, fMRI image sets were collected while participants were given identical noxious stimuli to all three cream sites. Pain intensity ratings were collected and placebo and nocebo responses determined. Brainstem-specific fMRI analysis revealed altered activity in key pain modulatory nuclei, including a disparate recruitment of the periaqueductal gray (PAG)-rostral ventromedial medulla (RVM) pathway when both greater placebo and nocebo effects were observed. Additionally, we found that placebo and nocebo responses differentially activated the parabrachial nucleus but overlapped in engagement of the substantia nigra and locus coeruleus. These data reveal that placebo and nocebo effects are generated through differential engagement of the PAG-RVM pathway, which in concert with other brainstem sites likely influences the experience of pain by modulating activity at the level of the dorsal horn.SIGNIFICANCE STATEMENT Understanding endogenous pain modulatory mechanisms would support development of effective clinical treatment strategies for both acute and chronic pain. Specific brainstem nuclei have long been known to play a central role in nociceptive modulation; however, because of the small size and complex organization of the nuclei, previous neuroimaging efforts have been limited in directly identifying how these subcortical networks interact during the development of antinociceptive and pro-nociceptive effects. We used ultra-high-field fMRI to resolve brainstem structures and measure signal change during placebo analgesia and nocebo hyperalgesia. We define overlapping and disparate brainstem circuitry responsible for altering pain perception. These findings extend our understanding of the detailed organization and function of discrete brainstem nuclei involved in pain processing and modulation.
Collapse
|
11
|
Stroman PW, Powers JM, Ioachim G, Warren HJM, McNeil K. Investigation of the neural basis of expectation-based analgesia in the human brainstem and spinal cord by means of functional magnetic resonance imaging. NEUROBIOLOGY OF PAIN (CAMBRIDGE, MASS.) 2021; 10:100068. [PMID: 34381928 PMCID: PMC8333346 DOI: 10.1016/j.ynpai.2021.100068] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 07/12/2021] [Accepted: 07/12/2021] [Indexed: 12/12/2022]
Abstract
Expectation of lower pain results in lower perceived pain in healthy humans. This expectation analgesia is mediated by descending regulation of the spinal cord. Connectivity analyses showed effects of expecting lower pain prior to stimulation. Expectation analgesia involves regions linked to arousal and autonomic regulation.
Purpose The expected intensity of pain resulting from a noxious stimulus has been observed to have a strong influence on the pain that is perceived. The neural basis of pain reduction, as a result of expecting lower pain, was investigated using functional magnetic resonance imaging (fMRI) in the brainstem and spinal cord. Methods Functional MRI studies were carried out in a region spanning the brainstem and cervical spinal cord in healthy participants. Participants were familiarized with a noxious heat stimulus and study procedures in advance, and were informed during each trial that either a heat calibrated to produce moderate pain (Base state), or a temperature 1 °C lower (Low state), would be applied to their hand. However, the Base temperature was applied in every trial. Results Pain ratings were significantly reduced as a result of expecting lower temperatures. FMRI results demonstrate blood oxygenation-level dependent (BOLD) signal variations in response to participants being informed of the stimulus to expect, in advance of stimulation, and in response to stimulation. Significant coordination of BOLD signals was also detected across specific brainstem and spinal cord regions, with connectivity strengths that varied significantly with the study condition, and with individual pain ratings. The results identify regions that are known to be involved with arousal and autonomic regulation. Conclusions Expectation-based analgesia is mediated by descending regulation of spinal cord nociceptive responses. This regulation appears to be related to arousal and autonomic regulation, consistent with the cognitive/affective dimension of pain.
Collapse
Affiliation(s)
- P W Stroman
- Centre for Neuroscience Studies, Queen's University, Kingston, Ontario K7L 3N6, Canada.,Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario K7L 3N6, Canada.,Department of Physics, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - J M Powers
- Centre for Neuroscience Studies, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - G Ioachim
- Centre for Neuroscience Studies, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - H J M Warren
- Centre for Neuroscience Studies, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - K McNeil
- Centre for Neuroscience Studies, Queen's University, Kingston, Ontario K7L 3N6, Canada.,Royal Military College of Canada, Kingston, Ontario K7L 3N6, Canada
| |
Collapse
|
12
|
Komann M, Baumbach P, Stamer UM, Weinmann C, Arnold C, Pogatzki-Zahn E, Meißner W. Desire to Receive More Pain Treatment - A Relevant Patient-Reported Outcome Measure to Assess Quality of Post-Operative Pain Management? Results From 79,996 Patients Enrolled in the Pain Registry QUIPS from 2016 to 2019. THE JOURNAL OF PAIN 2021; 22:730-738. [PMID: 33482323 DOI: 10.1016/j.jpain.2021.01.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 12/16/2020] [Accepted: 01/03/2021] [Indexed: 12/21/2022]
Abstract
Acute postoperative pain is frequently evaluated by pain intensity scores. However, interpretation of the results is difficult and thresholds requiring treatment are not well defined. Additional patient-reported outcome measures (PROMs) might be helpful to better understand individual pain experience and quality of pain management after surgery. We used data from the QUIPS pain registry for a cross-sectional study in order to investigate associations between the desire to receive more pain treatment (D2RMPT) with pain intensity ratings and other PROMs. Responses from 79,996 patients were analyzed, of whom 10.7% reported D2RMPT. A generalized estimating equation Poisson model showed that women had a lower risk ratio (RR) to answer this question with "yes" (RR: .92, P < .001). Factors that increased the risk most were "maximal pain intensity ≥ 6/10 on a numerical rating scale" (RR: 2.48, P < .001) and "any pain interference" (RR: 2.48, P < .001). The largest reduction in risk was observed if patients were "allowed to participate in pain treatment decisions" (RR: .41, P < .001) and if they felt that they "received sufficient treatment information" (RR: .58, P < .001). Our results indicate that the (easily assessed) question D2RMPT gives additional information to other PROMs like pain intensity. The small proportion of patients with D2RMPT (even for high pain scores) opens the discussion about clinicians' understanding of over- und under-treatment and questions the exclusive use of pain intensity as quality indicator. Future studies need to investigate whether asking about D2RMPT in clinical routine can improve postoperative pain outcome. PERSPECTIVE: This article presents characteristics of the patient-reported outcome measure "Desire to receive more pain treatment." This measure could be used to apply pain treatment in a more individualized way and lead to improved treatment strategies and quality.
Collapse
Affiliation(s)
- Marcus Komann
- Department of Anesthesiology and Intensive Care Medicine, Jena University Hospital, Jena, Germany.
| | - Philipp Baumbach
- Department of Anesthesiology and Intensive Care Medicine, Jena University Hospital, Jena, Germany
| | - Ulrike M Stamer
- Department of Anaesthesiology and Pain Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland; Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Claudia Weinmann
- Department of Anesthesiology and Intensive Care Medicine, Jena University Hospital, Jena, Germany
| | - Christin Arnold
- Department of Anesthesiology and Intensive Care Medicine, Jena University Hospital, Jena, Germany
| | - Esther Pogatzki-Zahn
- Department of Anesthesiology, Intensive Care and Pain Medicine, University Hospital Muenster, Münster, Germany
| | - Winfried Meißner
- Department of Anesthesiology and Intensive Care Medicine, Jena University Hospital, Jena, Germany
| |
Collapse
|