Physical pain among Indigenous Peoples in Canada: a scoping review.

PURPOSE: Pain is a multifaceted experience shaped by various factors including context of pain, previous life events, and ongoing ethnocultural circumstances. Moreover, the definition of pain is inconsistent across cultures. Western medicine views physical pain (e.g., associated with a bone fracture) and nonphysical mental pain (e.g., depression) as two distinct conditions. Indigenous perspectives are often more wholistic, encompassing mental, spiritual, emotional, and physical hurt. The subjective nature of pain invites ample opportunity for discrimination in both its assessment and management. As such, it is important to consider Indigenous perspectives of pain in research and clinical practice. To investigate which aspects of Indigenous pain knowledge are currently considered by Western research, we conducted a scoping review of the literature on pain in Indigenous Peoples of Canada. SOURCE: In June 2021, we searched nine databases and downloaded 8,220 papers after removal of duplicates. Two independent reviewers screened abstracts and full-text articles. PRINCIPLE FINDINGS: Seventy-seven papers were included in the analysis. Using grounded theory, five themes emerged: pain measures/scales (n = 7), interventions (n = 13), pharmaceuticals (n = 17), pain expression/experiences (n = 45), and pain conditions (n = 70). CONCLUSION: This scoping review shows that there is a paucity of research on pain measurement in Indigenous Peoples of Canada. This finding is concerning in light of numerous studies reporting that Indigenous Peoples experience their pain as ignored, minimized, or disbelieved. Furthermore, a clear disconnect emerged between pain expression in Indigenous Peoples and assessment in medical professionals. We hope that this scoping review will serve to translate current knowledge to other non-Indigenous academics and to initiate meaningful collaboration with Indigenous partners. Future research led by Indigenous academics and community partners is critically needed to better address pain needs in Canada.

RéSUMé: OBJECTIF: La douleur est une expérience multidimensionnelle façonnée par divers facteurs, notamment le contexte de la douleur, les événements antérieurs de la vie et les circonstances ethnoculturelles courantes. De plus, la définition de la douleur change d'une culture à l'autre. La médecine occidentale considère la douleur physique (par exemple, celle associée à une fracture osseuse) et la douleur mentale non physique (par exemple, la dépression) comme deux conditions distinctes. Les perspectives autochtones sont souvent plus holistiques, englobant les blessures mentales, spirituelles, émotionnelles et physiques. La nature subjective de la douleur ouvre la voie à de nombreuses possibilités de discrimination tant dans son évaluation que dans sa prise en charge. C'est pourquoi il est important de tenir compte des perspectives autochtones en matière de douleur dans la recherche et la pratique clinique. Afin d'étudier quels aspects des connaissances autochtones concernant la douleur sont actuellement pris en compte par la recherche occidentale, nous avons réalisé une étude de portée de la littérature sur la douleur chez les peuples autochtones du Canada. SOURCES: En juin 2021, nous avons consulté neuf bases de données et téléchargé 8220 articles après suppression des doublons. Deux personnes ont passé en revue et évalué de manière indépendante les résumés et textes intégraux. CONSTATATIONS PRINCIPALES: Soixante-dix-sept articles ont été inclus dans l'analyse. À l'aide de la théorie ancrée, cinq thèmes sont ressortis : les mesures/échelles de la douleur (n = 7), les interventions (n = 13), les produits pharmaceutiques (n = 17), l'expression/les expériences de la douleur (n = 45), et les conditions de douleur (n = 70). CONCLUSION: Cette étude de portée démontre le peu de recherches sur la mesure de la douleur chez les peuples autochtones du Canada. Cette conclusion est préoccupante à la lumière de nombreuses études indiquant que les peuples autochtones voient leur douleur ignorée, minimisée ou discréditée. De plus, un décalage évident est apparu entre l'expression de la douleur chez les peuples autochtones et l'évaluation par les professionnels de la santé. Nous espérons que cette étude de portée servira à transférer les connaissances actuelles à d'autres chercheurs et chercheuses non autochtones et à établir une collaboration significative avec des partenaires autochtones. Les recherches futures menées par des universitaires autochtones et des partenaires de la collectivité sont essentielles pour mieux répondre aux besoins en matière de douleur au Canada.

Excitatory and inhibitory responses in the brain to experimental pain: A systematic review of MR spectroscopy studies.

BACKGROUND: The role of the brain in processing pain has been extensively investigated using various functional imaging techniques coupled with well controlled noxious stimuli. Studies applying experimental pain have also used proton magnetic resonance spectroscopy (1H-MRS). The advantage of MRS compared to other techniques is the capacity to non-invasively examine metabolites involved in neurotransmission of pain, including glutamate, γ-aminobutyric acid (GABA), glutamate â€‹+ â€‹glutamine (Glx), and glutamine. OBJECTIVE: To systematically review MRS studies used in the context of studying experimental pain in healthy human participants. DATA SOURCES: PubMed, Ovid Medline, and Embase databases were searched using pre-specified search terms. ELIGIBILITY CRITERIA: Studies investigating glutamate, GABA, Glx and/or glutamine in relation to experimental pain (e.g., heat) in healthy participants via MRS. APPRAISAL CRITERIA: Each study was evaluated with a modified quality criterion (used in previous imaging systematic reviews) as well as a risk of bias assessment. RESULTS: From 5275 studies, 14 met the selection criteria. Studies fell into two general categories, those examining changes in metabolites triggered by noxious stimulation or examining the relationship between sensitivity to pain and resting metabolite levels. In five (out of ten) studies, glutamate, Glx and/or glutamine increased significantly in response to experimental pain (compared to baseline) in three different brain areas. To date, there is no evidence to suggest Glx, glutamate or glutamine levels decrease, suggesting an overall effect in favour of increased excitation to pain. In addition to no changes, both increases and decreases were reported for levels of GABA+ (=GABA â€‹+ â€‹macromolecules). A positive correlation between pain sensitivity and resting glutamate and Glx levels were reported across three studies (out of three). Further research is needed to examine the relationship of GABA+ and pain sensitivity. LIMITATIONS: A major limitation of our review was a limited number of studies that used MRS to examine experimental pain. In light of this and major differences in study design, we did not attempt to aggregate results in a meta-analysis. As for the studies we reviewed, there was a limited number of brain areas were examined by studies included in our review. Moreover, the majority of studies included lacked an adequate control condition (i.e., non-noxious stimulation) or blinding, which represent a major source of potential bias. CONCLUSION: MRS represents a promising tool to examine the brain in pain, functionally, and at rest with support for increased glutamate, glutamine and Glx levels in relation to pain. IMPLICATIONS: Resting and functional MRS should be viewed as complementary to existing neuroimaging techniques, and serve to investigate the brain in pain. Systematic review registration number- CRD42018112917.

Effectiveness of High-Frequency Electrical Stimulation Following Sensitization With Capsaicin.

UNLABELLED: Although nonnoxious, high-frequency electrical stimulation applied segmentally (ie, conventional transcutaneous electrical nerve stimulation [TENS]) has been proposed to modulate pain, the mechanisms underlying analgesia remain poorly understood. To further elucidate how TENS modulates pain, we examined evoked responses to noxious thermal stimuli after the induction of sensitization using capsaicin in healthy volunteers. We hypothesized that sensitization caused by capsaicin application would unmask TENS analgesia, which could not be detected in the absence of sensitization. Forty-nine healthy subjects took part in a series of experiments. The experiments comprised the application of topical capsaicin (.075%) on the left hand in the C6 dermatome, varying the location of TENS (segmental, left C6 dermatome, vs extrasegmental, right shoulder), and assessing rating of perception (numeric rating scale: 0-10) and evoked potentials to noxious contact heat stimuli. The extrasegmental site was included as a control condition because previous studies indicate no analgesic effect to remote conventional TENS. Conventional TENS had no significant effect on rating or sensory evoked potentials in subjects untreated with capsaicin. However, segmental TENS applied in conjunction with capsaicin significantly reduced sensation to noxious thermal stimuli following a 60-minute period of sensitization. PERSPECTIVE: The study indicates that sensitization with capsaicin unmasks the analgesic effect of conventional TENS on perception of noxious contact heat stimuli. Our findings indicate that TENS may be interacting segmentally to modulate distinct aspects of sensitization, which in turn results in analgesia to thermal stimulation.