Pain in Special Populations

Unravelling the Relationship Between Adverse Childhood Experiences, Post-traumatic Stress, and Pediatric Chronic Pain: An Integrative Examination

Children with chronic pain and their parents experience trauma symptoms at much higher rates than non-pain populations and trauma is linked to worse pain and functioning. Conceptual models of mutual maintenance posit that neurobiological, cognitive-behavioral, and interpersonal factors drive this relationship, but this has not yet been empirically shown in prospective research. Dr. Noel will present new prospective data from a cohort of treatment-seeking youth with chronic pain and their parents (N=200) integrating methods in brain-imaging eye-tracking, ecological momentary assessment, and activity monitoring demonstrating the roles of brain activation, cognitive biases, sleep disturbances and parent factors in the co-occurrence and maintenance of trauma (ACEs, PTSD) and pediatric chronic pain. Data demonstrating epigenetic and behavioural (parenting responses, sleep disturbances) mechanisms underlying the intergenerational  transmission of risk for pediatric chronic pain across generations will be presented. This will parallel preclinical findings from rodent model presented by co-presenter Dr. Mychasiuk. Overlapping epigenetic factors yielded from combining the animal and human models will be identified. New birth cohort data examining the role of parent ACEs in pregnancy and later development of chronic pain in adolescence, as well as underlying mechanisms, will also be presented. Implications for tailored, integrated interventions will be discussed.

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Traumatic Stress and Chronic Pain: Defence and Dysfunction

Early life injury can sensitize animals long term: it has been shown to produce lifetime peripheral sensitization in insects and cephalopods, and to adulthood in rodents. Injury in adulthood can likewise sensitize invertebrates long-term, producing systemically increased vigilance and readiness for defence. This is not entirely unlike the anticipation of threat, overinterpretation of threat and high amplitude defence seen in human post-traumatic stress and in chronic pain. But the translation cannot be so simply made, because in invertebrates this state is adaptive, and contributes directly to better survival, whereas in humans and rodents it does not appear to be associated with any benefits, and in humans is likely associated with earlier mortality. This talk will review the evidence and take an evolutionary approach to mechanisms that in ancestral times or in the wild may confer advantages, but do not do so in laboratory rodents or modern humans. Models of psychological trauma and of pain tend to focus on proximate mechanisms, such as mutual maintenance, which are important not least for therapeutic targets, but this focus takes too little account of ultimate (evolutionary) dynamics which take a more contextual account of behavioural options and biases resulting from early experience.

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Neurobiological Mechanisms Underlying the Relationship Between Early Life Trauma and Adolescent Pain

Early life adversity is associated with cognitive, social and emotional impairment. We have investigated the effects of a high fat /high sugar diet, and early life stress on pain sensitivity and emotional function in the Sprague Dawley rat, using maternal separation (MS) as a model of early adversity and neglect. We will demonstrate poor diets prime the inflammatory system to be sensitized to pain and impair social and emotional functioning. In addition, when compared to control offspring, MS pups display increased anxiety-like behaviour and an altered pain response, with increased pain thresholds indicative of increased risk for chronic pain in the future. Furthermore, using advanced MR imaging, we will demonstrate that high fat/high sugar diets and MS alter structural maturation of the brain, and that the effects of MS and poor diet are cumulative; both within the brain and on pain processing and socio-emotional function.

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The Intersection of Trauma and Pain: Translation across Children, Adults, and Animals

Painful experiences (e.g. surgeries, injuries) can be traumatic for individuals of any age, but adverse experiences and trauma in early life of humans and other mammals appear to have an important role in the development of enduring pain problems. Surprisingly little research has examined the trauma-pain relationship in early life or the underlying mechanisms that drive this over time, although it is evident that adverse early experience ‘sets’ the organism to anticipate high levels of threat and to be appropriately ready to mobilise defences, including pain. The focus of research has largely been on synergistic interactions of traumatic stress and pain in adulthood, both in terms of brain processing and of behaviour, and how to address either or both in treatment.

We will examine the relationships between physical and emotional trauma and pain across infancy, childhood, adolescence and adulthood, as well as the neurobiological, cognitive, behavioural, and interpersonal mechanisms that drive this relationship over time. New empirical findings will be rooted in recent and emerging evolutionary, cognitive-behavioural, and neurobiological models of trauma and pain and will inform advances in the prevention and treatment of pain and trauma across the lifespan.

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Pain Sensitivity and Chronic Pain During Critical Periods in Life- Studies in Neonatal, Adolescents and Elderly

Critical periods are stages in the lifespan of extensive changes in the human body characterized by a unique set of developmental and maturational changes. These changes affect the pain system in unique ways, leading to alterations in pain sensitivity and ultimately, the development of chronic pain. Identifying changes unique to each period will allow a better understanding of pain mechanisms and factors that contribute to pain sensitivity and chronic pain development. The current workshop will focus on cutting-edge research during three critical periods: neonatal, adolescence and late adulthood. First, Dr. Walker will present data related to the impact of preterm birth, neonatal intensive care and surgery on subsequent pain experience and somatosensory function in young adults. Dr. Nahman-Averbuch will describe the main changes during adolescence and will discuss how these changes affect pain in adolescents with and without chronic pain. Dr. Cruz-Almeida will speak about mechanism-based pain assessment in older individuals using multiple translational approaches (i.e., neuroimaging, epigenetics, QST). All speakers will discuss the distinct challenges associated with pain research and management in these populations as well as potential ways to optimize pain assessment and treatment. Additional considerations for the interaction between these critical periods will also be discussed.

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Pain and Injury in Childhood: Impact on Somatosensory Function

The developing nervous system is sensitive to altered activity, and pain and injury may have persistent effects that differ from those seen following the same exposure at older ages. This presentation will outline associations between pain at different developmental stages, following different forms of illness/injury, and subsequent somatosensory function. Longitudinal studies in an extremely-preterm birth cohort identified changes in sensory threshold that were more marked following neonatal surgery, with emergence of sex differences in late adolescence. Laboratory studies allow comparison of the efficacy of potential preventive interventions. A range of conditions in childhood (eg. genetic disorders, surgery, chemotherapy) produce peripheral neuropathic pain during adolescence. Quantitative sensory testing identified distinct sensory profiles (mechanical hyperalgesia, thermal hyperalgesia, sensory loss) that may improve recognition and management.

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Changes in Pain During Adolescence: What and Why

Adolescence is a critical period of development and forms the transition from childhood to adulthood. During adolescence and puberty, there are various changes to the nervous system that can affect pain. Sex differences in pain emerge during adolescence. There are no sex differences in chronic and experimental pain in children, however, adolescent females have a higher prevalence of chronic pain and are more sensitive to experimental pain. Changes in sex hormones are one potential explanation for the changes in pain sensitivity in adolescents. One of the main sex hormones, testosterone, was found to have an anti-nociceptive effect in animal and human studies. Dr. Nahman-Averbuch will present data on experimental pain sensitivity in healthy adolescents who are at early vs. late pubertal maturation. She will also present preliminary findings on the associations between higher testosterone levels and lower experimental pain responses in healthy adolescents. Differences in testosterone levels between males and females can be related to sex differences in pain sensitivity and the higher chronic pain prevalence that emerge around the age of puberty in females.

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Epigenetics and Pain in Older Adults

Dr. Cruz-Almeida will speak about mechanism-based pain assessment in older individuals using multiple translational approaches (i.e., neuroimaging, epigenetics, QST) along with their therapeutic implications. Specifically, she will describe how brain structure, function and biochemistry along with DNA methylation profiles may provide a unique understanding of the gene-environment interactions underlying chronic musculoskeletal pain in older age that may serve as a basis for future studies in biomarker development and targetable interventions. She will also highlight the need for pain cohort studies to further understand these mechanisms across the lifespan. 

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Mobilizing Knowledge about Pain in Dementia using Social Media

Traditional approaches to research knowledge mobilization (KM) (e.g., workshops, brochures, webinars), do not tend to succeed as most research findings never find their way into clinical practice. The minority of research findings, implemented into widespread practice, take an average of 17 years to get there. Older adults with severe dementia will not be around in 17 years to benefit from solutions that are available today. Based on the success of a previous social media KM effort in pediatric pain, we launched the #SeePainMoreClearly initiative to disseminate evidence-based information about pain in dementia to clinicians, informal caregivers and patients. We evaluated a 5-month pilot campaign, focused on Twitter and YouTube. We are now presenting new data on a year-long campaign involving a variety of platforms (Twitter, Instagram, Facebook, YouTube and LinkedIn) including web analytics (e.g., website visits, impressions, engagements, use of our hashtag, and video views), content analysis of posts in response to our content, questionnaires linked to our content, media stories, and interviews with people who engaged with us. Results show great reach (over 13,000,000 reached and 65,000 visited our resource website) and increased knowledge update by stakeholders. Recommendations, for launching successful KM campaigns via social media, will be provided.

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Pain Assessment in Dementia: Guidelines, Gaps, Automation and Knowledge Mobilization

Pain in people with serious limitations in ability to communicate due to dementia is highly prevalent but frequently undertreated. Despite recent developments in validated observational approaches to pain assessment in dementia, there remain implementation challenges as well as gaps in research knowledge and in continuing education for health care providers. In this session we will describe the state-of-the-art in specialized assessment tool development, including efforts to automatize pain assessment using computer vision. Moreover, emphasis will be placed on knowledge mobilization, designed to help overcome existing clinician continuing education and evidence-based assessment implementation challenges, including systematic evaluation of the reach and impact of the #SeePainMoreClearly pain in dementia knowledge dissemination campaign using a variety of social media platforms. We will offer practical advice on assessment tool selection and on effectively reaching stakeholders through knowledge mobilization.

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