Evidence Based Assessment of Pain in Displaced Persons

Original Editor - Zafer Altunbezel

Top Contributors - Naomi O'Reilly, Ewa Jaraczewska, Wanda van Niekerk, Jess Bell and Kim Jackson  

Introduction[edit | edit source]

Prolonged conflicts, forced displacement and mass migration continue to be major issues in the 21st Century. In 2021 at least 89.3 million people around the world have been forced to flee their homes due to conflicts, violence, fear of persecution and human rights violations. Nearly 27.1 million refugees are in this group, and around half of whom are under the age of 18.[1] Whether in a camp for displaced persons next to an active conflict zone or a safe third country, multiple and complex health problems of displaced persons are becoming a big problem for healthcare workers. 

Regardless of type and severity, trauma has the potential to impact the biological, psychological and social well-being of the individuals. Traumatised displaced persons often report significant levels of chronic pain in addition to symptoms of Post Traumatic Stress Disorder.[2] Studies indicate a high prevalence of the presence of a persistent pain in torture survivors, with an overall incidence of up to 83%.[3]

The clinical picture may include headaches, neck pain, back pain, extremity pain and regional or widespread pain. Psychological disorders and other co-morbid conditions may be interacting with persistent pain. Therefore, chronic pain may be very complex for clinicians in some cases due to its multifactorial nature. Proper assessment and treatment of chronic pain in displaced persons require an understanding of traumatic experiences of displaced persons and their consequences on different determinants of health. 

Traumatic Experiences Contribute to Development of Chronic Pain [edit | edit source]

Displaced persons are frequently exposed to different types of traumatic events, which may lead to the development of pain and other relevant health problems both in their origin countries and on the migration routes. Usually, these experiences have repetitive and continuous character. It is not unusual to see that such traumatic events continue to happen in second or third countries.   

Displaced persons often experience multiple traumatic experiences causing complex and interacting biological, psychological and social impacts on their well-being. Due to its complex and multifactorial nature, chronic pain in displaced persons might be exhausting for clinicians to deal with and always require the involvement of different clinical disciplines. Having adequate knowledge about common experiences of displaced persons is of utmost importance in order to make a thorough assessment of pain and rule out serious medical conditions that can risk both patient’s and clinician’s safety. Common traumatic experiences of displaced persons include but are not exclusive to:  

War and Conflict[edit | edit source]

Wars and conflicts are causing the displacement of millions of people each year. Civilians are typically targeted by armed assaults, aerial attacks, improvised explosive devices, landmines or chemical weapons. A high number of people sustain war injuries such as gunshot wounds, burns, amputations and complex trauma. Various mental health disorders such as PTSD, depression and sleeping problems may occur after being exposed to or witnessed to these traumatic events. Moreover, disruption of the health system and other infrastructure may cause deprivation of healthcare and basic needs. All these factors create an environment for the development of chronic pain and other health issues. 

Torture and Ill-Treatment[edit | edit source]

Despite all the international efforts, torture is still being used worldwide, especially in war zones and in countries where political oppression is present. Individuals can be randomly or deliberately detained or kidnapped and tortured for interrogations, spreading terror or demanding ransom. Displaced persons can also be exposed to torture and violence on their migration route by smugglers or different armed actors. Physical torture such as blunt violence, suspension, electrocution, forced physical positions etc. and psychological violence such as threats, humiliation, and mock execution are just some of the common methods of torture seen. Sexual violence is often used against people regardless of age or gender. Torture results in severe physical and psychological consequences but despite its severity, its impact may be invisible due to feelings of shame, insecurity or stigmatisation. 

Imprisonment[edit | edit source]

Illegal imprisonment and detentions based on ethnic, political or religious orientation and long-term prison sentences exceeding decades without fair trial are often seen in countries having conflict and political instability. In addition to the risk of torture and ill-treatment, extremely unhealthy conditions may be present in prisons. Extremely crowded cells, lack of hygiene, deprivation of clean food and water-sometimes even sunshine, inaccessibility of healthcare and the psychological impact of captivity as well and witnessing ill-treatment in prison are important risk factors both for physical and psychological well-being. These conditions may also lead to the spread of communicable diseases, worsening of existing non-communicable chronic diseases, general decrease in biological health, physical condition and development of psychological disorders. 

Precarious Living Conditions[edit | edit source]

Disruption of infrastructure, forced displacement and inhuman conditions in camps for displaced persons and host countries are the factors leading displaced persons to live under precarious conditions. The absence of healthcare, psychosocial services and even basic fundamental needs are causing a gradual decrease in an individual’s health status. In some host countries where resources for social support are insufficient, displaced persons are often exposed to labour exploitation while struggling to earn a livelihood. Working long hours in heavy labour jobs and frequent job accidents are causing the development of secondary injuries in addition to their traumatic experiences. Failure to establish basic stability in daily life may increase the severity of existing health problems and hinder physical and mental healing. 

Figure.1 Traumatic Experience of Displaced Persons

Consequences of Trauma on Health[edit | edit source]

Traumatic experiences of displaced persons cause multiple complex and interacting consequences on their health. Physical and psychosocial trauma as well as the development of communicable and non-communicable diseases may result in a risk of early death, disability, decreased quality of life and chronic pain. Being aware of possible scenarios allows clinicians to detect red flags, make a thorough assessment and identify the main problems to be addressed. 

Physical Consequences[edit | edit source]

Various traumatic orthopaedic and neurological injuries may be seen in people who have experienced displacement. Some types of traumatic injuries such as pelvic trauma, amputations, spinal cord injury and traumatic brain injury may require special training in order to gain adequate clinical skills. 

Table.1 Physical Consequences of Trauma on Refugee Health
Physical Consequences
Soft Tissue Injury
Arthritis and Arthrosis
Gunshot Wounds
Spinal Cord Injury
Peripheral Nerve Injury
Traumatic Brain Injury
Pelvic and Genital Trauma

Psychosocial Consequences[edit | edit source]

Inadequate attitudes or approaches to individuals with traumatic psychological conditions have the potential to cause re-traumatisation. Some mental health disorders such as PTSD and sleep disturbances can easily interact with chronic pain and hinder treatment. Social issues commonly experienced by displaced persons can negatively impact the participation and commitment of individuals to the rehabilitation process.

Table.2 Psychosocial Consequences of Trauma on Refugee Health
Psychosocial Consequences
Sleeping Disorders
Somatic Disorders
Psychotic Disorders
Livelihood Issues
Nutrition Issues
Access to Health

Communicable and Non-Communicable Diseases[edit | edit source]

Although it seems like it is within the focus of physicians, rehabilitation professionals working with displaced persons must have enough knowledge about common communicable and non-communicable diseases in their patient population. Detecting any clinical red flags and ensuring proper referral is of importance for both patients’ and clinicians’ safety.

Table.3 Communicable and Non-Communicable Diseases
Communicable and Non-Communicable Diseases
Cardiovascular Disease
Respiratory Diseases
Gastrointestinal Disease
Urinary and Gynaecological Disease
Neurological Disease
Rheumatological Disease
Metabolic Disease
Endocrinological Disease

In summary, traumatic experiences of displaced persons are often resulting in interacting biological, psychological and social consequences. Multiple complex health problems may exist at the same time and these problems are mostly detected in the chronic phase. In treatment, external resources such as involvement of multiple disciplines, imaging and medical interventions as well as internal resources such as trust relationship, resilience and commitment of the individual are often needed.

Integration of Modern Pain Theories into Health for Displaced Persons[edit | edit source]

Rehabilitation professions have witnessed great improvements in pain sciences during recent years and clinicians have started to adopt the bio-psycho-social approach and novel techniques in the treatment of chronic pain. Rehabilitation for displaced persons is often provided within a brief and limited time with minimal resources. Integration of some modern pain concepts into the clinical reasoning process, such as peripheral sensitisation, abnormal impulse generating sites, central sensitisation, autonomic and immune system contributions and psychosocial factors, can enhance overall success in rehabilitation.

Peripheral Sensitisation[edit | edit source]

International Association for the Study of Pain (IASP) defines peripheral sensitisation as “increased responsiveness and reduced threshold of nociceptors to stimulation of their receptive fields". It is also named primary hyperalgesia. Peripheral sensitivity occurs following an injury with the aim of protecting the injured site from further damage. Inflammatory chemicals released from the injury sites as well as nerves themselves and immune system cells play an active role in peripheral sensitivity. As nociception or inflammation persists, up-regulation of existing and new ion channels in the nerve occurs. 

Being a useful and protective physiological response at the beginning, peripheral sensitisation may eventually lead to central sensitisation. Therefore detecting and managing the peripheral sensitisation is important to prevent negative outcomes.

Abnormal Impulse Generating Sites[edit | edit source]

Abnormal Impulse Generating Sites (AIGS) are defined as the damaged sites along the nerve in which the number, kind and excitability of ion channels are altered. When injured, a segment of a peripheral nerve may develop the ability to repeatedly generate its own impulses. Spontaneous activity and mechano-sensitivity are the main features of an AIGS.[4] An AIGS fires antidromically and orthodromically, resulting in constant noxious stimulus into the Central Nervous System and neurogenic inflammation in the tissues. 

AIGS can develop anywhere along the nerve where nerve tissue is compromised including dorsal root ganglion. Traumatic experiences of displaced persons such as explosions, gunshot wounds, burns or different methods of torture may cause excessive compression, traction or direct injury of the nerve and surrounding connective tissue and thus leading to the development of AIGS.  

Central Sensitisation[edit | edit source]

Central sensitisation corresponds to an enhancement in the functional status of neurons and circuits in nociceptive pathways throughout the neuraxis caused by increases in membrane excitability, synaptic efficacy, or a reduced inhibition. [5] 

Central sensitisation is characterised by allodynia, hyperalgesia, expansion of the receptive field and unusually prolonged pain after the stimulus has been removed. A number of explanations have been proposed to explain the development of central sensitisation, including dysregulation in both ascending and descending central nervous system pathways due to physical trauma and sustained pain impulses, and the chronic release of pro-inflammatory cytokines by the immune system, as a result of physical trauma or viral infection.[6] In addition, it is well-recognised that psychiatric disorders, including anxiety, panic and depression, are often associated with central sensitisation.[7][8] Due to the interaction between psychosocial factors and biological mechanisms, it has been recommended that central sensitisation be viewed within a bio-psycho-social model. [9] 

Given the chronicity and complexity of the pain experience of many displaced persons, central sensitisation is one of the important factors likely to be involved in the clinical picture. Overlooking the presence of central sensitisation may lead to false assumptions about the patient such as psychosomatic pain or secondary benefit as well as failure in treatment.

Autonomic and Immune System Contributions[edit | edit source]

Stress neurobiology has only recently been associated with the neurobiology of pain.[10] Systems such as the endocrine, immune, motor and autonomic are central protective systems, yet while they can protect and heal, something which requires considerable power, they can also damage, especially in states of maintained stress and pain.[11]

Cortisol, one of the critical hormones for homeostasis, is secreted from the adrenal cortex by the triggering effect of the Hypothalamus-Pituitary-Adrenal Axis (HPA). In an emergency, cortisol shuts down activities not needed for survival and enhances those that are. Hence the inflammatory and immune systems, digestive and reproductive systems are shut down. A chronic excess of cortisol as in chronic pain or stress poses problems. The features include immuno-suppression, osteoporosis, cardiovascular disease, depression and insulin resistance.[12] More subtle cases of tissue degeneration, mood swings, slow tissue healing and susceptibility to infection may be noted by clinicians managing patients with chronic pain.[13]          

Mental and physical effects and psychosocial conditions evoke adrenaline and noradrenaline secretions. They stimulate a sympathetic response in order to prepare the organism for action. Adrenaline and noradrenaline are useful secretions for emergency situations, but like cortisol, maintained high levels lead to the risk of cardiovascular disease and tissue damage. The sympathetic nervous system can contribute to the sensitivity of inflamed tissues and it can also contribute to the sensitivity of damaged nerves. Noradrenaline pathways in the brain are also closely linked to negative emotional states.[14]

Cytokines secreted by the immune system in response to different physical and emotional stressors can modulate inflammation and pain. While some cytokines such as Interleukin-1, Interleukin-2 and Tumor Necrosis Factor Alfa are pro-inflammatory other cytokines such as Interleukin-4, Interleukin-10 and Interleukin-13 are anti-inflammatory. The immune system is closely linked to the peripheral and central nervous system thus any stressor having an impact on the nervous system can also result in immunity changes. 

Displaced persons are often exposed to repetitive physical and mental stressors. Given the long-term exposure to stress and pain, dysfunctional physiological changes in stress response systems are likely to present and it can be the main driving mechanism behind multiple physical problems and chronic pain. Therefore physiological effects of stress should be evaluated. 

Psychosocial Factors [edit | edit source]

Within a bio-psycho-social approach, the effect of mental health and social domains that are frequently impaired by trauma can not be overlooked. Variables such as attitudes, beliefs, mood state, social factors and work appear to interact with pain behaviour and are cumulatively referred to as psychosocial factors.[15]

Comprehensive assessment of pain in trauma survivors should always include the evaluation of psychosocial factors, which can be the main driving factor behind the persistence of pain. Studies found that increased PTSD symptoms are related to increased pain levels, pain disability and widespread pain.[16] 40-50% of chronic pain patients experience depression and pain[17], which may lead to decreased physical activity and insufficient participation in treatment. Chronic pain can interfere with sleep and sleep disturbance may impair pain-inhibitor function,[18] as well as tissue healing. Unhelpful cognitive processes and behaviours about the pain such as catastrophising, fear of pain or movement, filtering, polarised thinking, and passive coping strategies may frequently contribute to the pain experience. Finally, social factors such as access to fundamental needs, stigmatisation, lack of social support, legal status, financial concerns and work issues may have reflections on pain experience. 

Assessment Using the Pain and Disability Drivers Model[edit | edit source]

Given the long-term and repetitive traumatic experiences as well as the multifactorial nature of pain in traumatised displaced persons, the Pain and Disability Drivers Model (PDDM) may provide an effective framework for clinicians assessing pain. PDDM is originally developed for the management of low back pain [19] but it can be applied to other forms of chronic pain. 

Fig.2 Pain and Disability Driver Model

PDDM describes five main domains that may be contributing to pain and disability. There are also key assessment elements and findings under each domain. Different domains interact with each other in a bi-directional concept, meaning that a change in one of the domains can have positive or negative effects on other domains. To understand the whole picture of pain and disability, the key elements and findings should be identified and a mapping of all the elements should be made. Understanding the weight of each contributing domain will help clinicians to direct their interventions to the most needed factors.   

Nociceptive Pain Drivers [edit | edit source]

Nociceptive pain is “pain that arises from actual or threatened damage to non-neural tissue and is due to the activation of nociceptors”. [20] Nociceptive input, as the most frequent initiating factor of many chronic painful conditions, should be targeted initially if any presence is detected. 

Explosions, blunt trauma, torture and other forms of traumatic experiences, as well as domestic events, may result in different orthopaedic injuries creating severe nociceptive input. Despite the chronicity of pain in most traumatised displaced persons, nociceptive input may be still ongoing due to re-traumatization, absence of treatment, improper healing, general immobility or unhelpful behaviours. 

Key Assessment Elements and Findings:[edit | edit source]

  • Symptom Modulation (Pain triggered by a specific movement pattern)
  • Movement Control (Pain triggered by functional stability deficits)
  • Mobility and Pain (Pain caused by increased or decreased mobility)
  • Nonspecific De-conditioning (Pain caused by general deconditioning)
  • Structural Stability Deficits  (Pain caused by actual structure damage e.g. joint dislocations, ligament ruptures) [19]

Careful physical examination based on anamnesis; including inspection, palpation and functional tests can reveal the key findings above and shift the focus of treatment towards local tissue-based treatments. 

Nervous System Dysfunctions Drivers[edit | edit source]

Given the fact that multiple physical trauma and long-term neglect of its consequences are the common characteristics of trauma in displaced persons, examining the presence of any nervous system dysfunction is essential in the assessment. Pain from the nociceptive origin and nervous system dysfunction have important differences in their underlying mechanisms as well as treatment options. 

Key Assessment Elements and Findings:[edit | edit source]

If the presence of neuropathic pain is suspected through the patient’s history or clinical signs (for example; paresthesia, dysesthesia, hyperalgesia), the following measurement tools can be used to either rule in or out:

  • Douleur Neuropathique en 4 Questions (DN4) 
  • Leeds Assessment of Neuropathic Symptoms and Signs (LANNS)
  • Neuropathic Pain Questionnaire
  • painDETECT

Aside from neuropathic pain, central sensitisation might be an important factor in persistence of pain. Clinical signs such as general fatigue, mechano-sensitivity, allodynia, widespread pain or incompatible presentation with actual physical status should raise doubts about central sensitisation. The following tool can be used for the assessment of central sensitivity. 

Co-morbidity Pain and Disability Drivers[edit | edit source]

Co-morbidity refers to the presence of one or more additional conditions often co-occurring with a primary condition. Traumatic experiences and precarious living conditions in war zones, prisons and displaced persons settlements may often lead to increases incommunicable and non-communicable diseases as well as mental health disorders. 

Figure: Common CDs/NCDs in refugees.

Since long-term inaccess to healthcare is a common experience in displaced persons, assessment of the co-morbidities is essential in pain assessment. A thorough medical examination may not have happened prior to accessing rehabilitation services and any kind of life-threatening condition, red flags and hidden factors contributing to the persistence of pain may be present. That’s why a detailed medical examination and screening of co-morbidities should be ensured. 

Key Assessment Elements and Findings [edit | edit source]

The Charlson Comorbidity Index (CCI) and the Elixhauser Comorbidity Index (ECI) are the two best-known indices in the field of patient risk adjustment and outcome prediction [21][22] 

Persistent pain has a well-proven impact on sleep but the relationship between both phenomena is bidirectional since disturbed sleep affects pain perception by lowering the pain threshold.[23] Lack of sleep hygiene also has negative effects on tissue healing and mental health. Therefore the quality of sleep should be questioned in patients with chronic pain. 

Cognitive and Emotional Pain and Disability Drivers[edit | edit source]

Through scientific research, we are now aware of the thought processes which are powerful enough to maintain a pain state.[24] Unhelpful cognitions about pain not only contribute to the persistence of pain but also increase the level of pain-related disability. 

Displaced person populations that are deliberately traumatised and left helpless for a long time provide a suitable environment for developing negative cognitions and emotions about pain. Lack of health literacy, harmful cultural beliefs and thoughts about pain may direct people to negative coping strategies.

Key Assessment Elements and Findings [edit | edit source]

  • Catastrophisation, filtering or polarized thinking [25]
  • Fear of Pain and Movement
  • Low Self-efficacy
  • Low expectations toward treatment and healing
  • Pain-related behaviours (facial or verbal expressions, guarding, changes in daily activities)

Negative cognitions and emotions may be an important barrier to establishing a cooperative relationship with the patients and lead to non-compliance and poor outcomes. The following tools can be used in assessing cognitive factors:

Social and Environmental Disability Drivers[edit | edit source]

Displaced persons are often dealing with precarious living conditions and socioeconomic constraints in their daily lives. While focusing too much on physical and psychological elements, social determinants of health can be overlooked by clinicians. For a successful assessment of pain, the clinician should have a general overview of the social and economical situation of the individual.

Key Assessment Elements and Findings[edit | edit source]

  • Legal Status
  • Access to Basic Needs 
  • Access to Healthcare
  • Economic Stability
  • Security in the living space and community

Gaps in the key factors above may be the hidden factor behind the poor outcomes or non-compliance to treatment. Therefore, proper referrals to social support resources should be ensured. 

Assessment in Practice[edit | edit source]

Once the clinician develops a good understanding of the traumatic experiences of displaced persons and their reflections on different determinants of health, good practice in the assessment of pain can be guaranteed.

The first and most important aim of an assessment session is to build a trusting relationship with the patient. Without building trust and cooperation, no benefit can be expected from the physiotherapy process. In every step of assessment and treatment, the general principles of the trauma-informed care model must be implemented to prevent re-traumatisation.

The points will be described below can be used as a practical framework while planning and conducting an assessment. The order of these points may change based on the needs and information provided by other professionals.

Preparation[edit | edit source]

  • Setting of the room should be arranged prior to the session. This can include a seating plan, treatment table, curtains, forms, assessment equipment, hygiene materials etc.
  • Related background information should be obtained from referring professional with the consent of the patient.
  • If a translator or cultural mediator is involved in the session, they should be briefed before the session.

Starting the Session[edit | edit source]

  • The patient should be welcomed with respect and kindness by showing importance to cultural sensitivities. (e.g. shaking hands, direct eye contact etc.)
  • A general introduction including reason and aim of that session, scope of the therapist, role of the therapist, details of the interview and examination should be made to the patient.
  • It must be clearly explained that the patient will have control over the session and may pause or stop it whenever he or she needs it.
  • After the introduction, feedback regarding the patient’s expectations and cautions (if any) should be obtained.

Medical History[edit | edit source]

Following details should be collected by continuously observing the patient’s reactions and the number of questions should be decreased if there is any negative reaction observed from the patient. This part should happen in an atmosphere of friendly conversation rather than a detailed interrogation.

  • Main complaints which motivated the patient to seek help
  • Location and the distribution of pain as well as the type of pain for each location
  • Chronological details of the onset and progress of the pain
  • Mechanism of the injury and pain, be cautious about potential sensitivities
  • Pain Intensity, preferably both subjective and on a numeric or visual scale
  • Daily course of the pain
  • Aggravating and relieving factors of pain
  • Sleep Disturbance
  • Previous medical interventions

Ideally, the patient should undergo an initial medical and mental health assessment prior to the rehabilitation professional assessment. The following information regarding co-morbidities should be asked either from referring professional or the patient.

  • Presence or suspicion of any current or previous communicable disease (tuberculosis, hepatitis etc.)
  • Presence or suspicion of any current or previous non-communicable disease (heart disease, hypertension, diabetes etc.)
  • Presence of any mental health disorder (PTSD, Depression, Anxiety etc.) or any psychological symptom causing distress

In addition to the routinely collected information, the clinician should try to understand the patient’s subjective pain experience through the following points.

  • The meaning of pain for themselves and their lives. While some patients see the pain as a temporary, treatable condition; other patients may see it as a permanent sequel of traumatic experiences due to personal or cultural factors.
  • Patient's beliefs about the cause of his or her pain. The reason thought by the patient can be a particular event (e.g. torture) or a structural explanation (e.g. disc herniation).
  • Patient’s beliefs, expectations and plans about the treatment of pain. While some patients have positive motivation for physiotherapy and exercise, others may see medical or surgical interventions as the only solutions.
  • Presence of fear of pain and movement and linked withdrawal from physical activity.
  • Presence of hopelessness or catastrophisation.
  • Patient’s perception of self-efficacy as well as physical incapacitation.
  • Socioeconomic details which may be related to pain (e.g. unemployment or long working hours, house without proper heating, nutrition, absence of private space or secure neighbourhood for physical activity, family support, stigmatization)

To supplement the qualitative information collected during the interview, related outcome measures explained in PDDM sub-domains can be used.

Physical Evaluation[edit | edit source]

In every step of the physical evaluation, general principles of the trauma-informed care model should be implemented. Breaching the patient’s boundaries may result in re-traumatization and loss of trust.

  • Inspection including posture, deformities, gait, transfers and guarding movements
  • Localisation of pain through patient’s guidance and palpation
  • Movement testing including active, passive and accessory movements
  • Functional and specific physical tests
  • Muscle strength and endurance assessment
  • Neurological Assessment including sensation, reflex and neural tension tests
  • Balance Assessment

Analysing Findings and Delivering Results[edit | edit source]

It’s essential to keep in mind that individuals suffering from pain expect a conceivable explanation about the reason for their pain and meeting this expectation is one of the essential steps in building a therapeutic relationship.

  • Based on the information collected during the interview, the clinician should analyse the weight of each main domain of PDDM and make a mapping of the contributors.
  • Identified contributing factors should be explained to the patient by taking their current beliefs and capacity to understand into account.
  • While explaining the findings, the use of terms and concepts which can cause catastrophisation should be minimised (for example; wear and tear, rupture, herniation).
  • Communication should be bi-directional,  feedback regarding provided explanation and whether it is received should be asked from the patient.
  • In addition to an explanation of causes of pain, important points such as how rehabilitation can help, estimated treatment duration, expected outcomes, rules and bilateral responsibilities should be discussed with patients in order to set the frame of the treatment process.

Case Examples[edit | edit source]

Evidence Based Assessment of Pain in Displaced Persons - Case Study 1

Evidence Based Assessment of Pain in Displaced Persons - Case Study 2

Resources[edit | edit source]

References[edit | edit source]

  1. UNHCR. “Figures at a Glance.” The UN Refugee Agency, 2020, https://www.unhcr.org/figures-at-a-glance.html. Accessed 18 October 2020.
  2. Teodorescu DS, Heir T, Siqveland J, Hauff E, Wentzel-Larsen T, Lien L. Chronic pain in multi-traumatized outpatients with a refugee background resettled in Norway: a cross-sectional study. BMC Psychol. 2015 Mar 15;3(1):7. doi: 10.1186/s40359-015-0064-5. PMID: 25815196; PMCID: PMC4369066.  
  3. Olsen DR, Montgomery E, Bøjholm S, Foldspang A. Prevalent musculoskeletal pain as a correlate of previous exposure to torture. Scandinavian Journal of Public Health. 2006;34(5):496-503. doi:10.1080/14034940600554677
  4. Butler, D. (2000). The Sensitive Nervous System. (p.61) Noigroup Publications.
  5. Latremoliere A, Woolf CJ. Central sensitization: a generator of pain hypersensitivity by central neural plasticity. J Pain. 2009 Sep;10(9):895-926. doi: 10.1016/j.jpain.2009.06.012. PMID: 19712899; PMCID: PMC2750819.
  6. Yunus MB. Central sensitivity syndromes: a new paradigm and group nosology for fibromyalgia and overlapping conditions, and the related issue of disease versus illness. Semin Arthritis Rheum. 2008 Jun;37(6):339-52. doi: 10.1016/j.semarthrit.2007.09.003. Epub 2008 Jan 14. PMID: 18191990.
  7. Ang D, Chakr R, France C, et al. Association of nociceptive responsivity with clinical and the moderating effect of depression. Journal of Pain. 2011;12:384–389.
  8. Petersel D, Dror V, Cheung R. Central amplification and fibromyalgia: Disorder of pain processing. Journal of Neuroscience Research. 2011;89:29–34.
  9. Yunus MB. Role of central sensitization in symptoms beyond muscle pain, and the evaluation of a patient with widespread pain. Best Practices in Research and Clinical Rheumatology. 2007;21(3):481–491.
  10. Gifford L, Pain, the Tissues and the Nervous System: A conceptual model. Physiotherapy. 1998 Jan; 84. 27-36. 10.1016/S0031-9406(05)65900-7.
  11. Butler, D. (2000). The Sensitive Nervous System. (p.84) Noigroup Publications.
  12. Whitehouse BJ (2000) Adrenal Cortex. In: Fink G (ed.) Encyclopedia of Stress, Academic Press, San Diego
  13. Butler, D. (2000). The Sensitive Nervous System. (p.86) Noigroup Publications.
  14. Butler, D. (2000). The Sensitive Nervous System. (p.88) Noigroup Publications.
  15. Innes SI. Psychosocial factors and their role in chronic pain: A brief review of the development and current status. Chiropr Osteopat. 2005 Apr 27;13(1):6. doi: 10.1186/1746-1340-13-6. PMID: 15967055; PMCID: PMC1151654.
  16. Beckham JC, Crawford AL, Feldman ME, Kirby AC, Hertzberg MA, Davidson JR, Moore SD. Chronic posttraumatic stress disorder and chronic pain in Vietnam combat veterans. J Psychosom Res. 1997 Oct;43(4):379-89. doi: 10.1016/s0022-3999(97)00129-3. PMID: 9330237
  17. Pain: Clinical Updates. Anxiety and Pain. December 2004 (Volume 12, Issue 7) Ingela Symreng and Scott M. Fishman
  18. Smith MT, Haythornthwaite JA. How do sleep disturbance and chronic pain inter-relate? Insights from the longitudinal and cognitive-behavioural clinical trials literature. Sleep Med Rev. 2004 Apr;8(2):119-32. doi: 10.1016/S1087-0792(03)00044-3. PMID: 15033151.
  19. 19.0 19.1 19.2 Tousignant-Laflamme Y, Martel MO, Joshi AB, Cook CE. Rehabilitation management of low back pain - it's time to pull it all together! J Pain Res. 2017 Oct 3;10:2373-2385. doi: 10.2147/JPR.S146485. PMID: 29042813; PMCID: PMC5633330.
  20. IASP Taxonomy - IASP [Accessed February 6, 2017].
  21. Charlson ME, Pompei P, Ales KL, MacKenzie CR. A new method of classifying prognostic comorbidity in longitudinal studies: development and validation. J Chronic Dis. 1987;40(5):373-83. doi: 10.1016/0021-9681(87)90171-8. PMID: 3558716.
  22. Elixhauser A, Steiner C, Harris DR, Coffey RM. Comorbidity measures for use with administrative data. Med Care. 1998 Jan;36(1):8-27. doi: 10.1097/00005650-199801000-00004. PMID: 9431328.
  23. Frohnhofen H. Pain and sleep : A bidirectional relationship. Z Gerontol Geriatr. 2018 Dec;51(8):871-874. English. doi: 10.1007/s00391-018-01461-8. Epub 2018 Oct 26. PMID: 30367215.
  24. Butler, D. S., & Moseley, G. L. (2003). Explain pain. (pp.73-74) Adelaide: Noigroup Publications.
  25. Nielsen, H. F. (2014). Interventions for physiotherapists working with torture survivors. DIGNITY – Danish Institute Against Torture. https://www.dignity.dk/wp-content/uploads/pubseries_no6.pdf