Anneleen Malfliet

Treatment of central sensitization in patients with 'unexplained' chronic pain: an update

Introduction: Central sensitization (CS) is present in a variety of chronic pain disorders, including whiplash, temporomandibular disorders, low back pain, osteoarthritis, fibromyalgia, headache, lateral epicondylalgia among others. In spite of our increased understanding of the mechanisms involved in CS pain, its treatment remains a challenging issue. Areas covered: An overview of the treatment options we have for desensitising the CNS in patients with CS pain is provided. These include strategies for eliminating peripheral sources of nociception, as well as pharmacotherapy and conservative interventions that primarily address top-down (i.e., brain-orchestrated) mechanisms. Expert opinion: A combination of different strategies, each targeting a different ‘desensitizing’ mechanism, might prove superior over monotherapies. Such combined therapy may include both bottom-up and top-down (e.g., opioids, combined μ-opioid receptor agonist and noradrenaline reuptake inhibitor drugs) strategies. Topically applied analgesic therapies have strong potential for (temporally) decreasing peripheral nociceptive input (bottom-up approach). Targeting metabolic (e.g., ketogenic diets) and neurotrophic factors (e.g., decreasing brain-derived neurotrophic factor) are promising new avenues for diminishing hyperexcitability of the CNS in central sensitization pain patients. Addressing conservative treatments, pain neuroscience education, cognitive behavioural therapy and exercise therapy are promising treatments for CS pain.

Structural and functional brain abnormalities in chronic low back pain: A systematic review ☆

OBJECTIVES The purpose of this systematic review is to analyze the available literature on structural and functional brain abnormalities in chronic low back pain (CLBP) using several brain magnetic resonance imaging (MRI) techniques. METHODS PubMed and Web of Science were systematically screened for relevant literature using different combinations of keywords regarding structural and functional brain imaging techniques in patients with CLBP. Reference lists of included articles were hand-searched for additional literature. Eligible articles were assessed on risk of bias and reviewed by two independent researchers. RESULTS The search query returned 27 articles meeting the inclusion criteria. Methodological quality varied from poor to good. A total of 10 studies evaluated structural gray matter changes. There is conflicting evidence in global gray matter changes, with both increases and decreases shown in different studies. Gray matter changes were demonstrated in specific brain regions. Structural white matter changes were reported in five studies. There is conflicting evidence in total white matter volume due to both increases and unchanged white matter. Several regional differences were identified in which white matter changes were shown. Functional organization during rest was evaluated in 10 studies. CLBP patients showed increased activation in specific regions, together with a disrupted default mode network. A total of six studies evaluated brain activity in response to a nociceptive stimulus. Findings suggest that patients demonstrated increased activity in pain-related regions, and decreased activity in analgesic regions. CONCLUSIONS Overall, there is moderate evidence for regional changes in gray and white matter, together with an altered functional connectivity during rest and increased activity in pain-related areas following painful stimulation, evidencing an upregulated pain matrix. More longitudinal research is needed to clarify the temporal relationship regarding pain and neuroplastic changes, and integration of different brain imaging techniques is warranted.

Brain changes associated with cognitive and emotional factors in chronic pain: A systematic review

An emerging technique in chronic pain research is MRI, which has led to the understanding that chronic pain patients display brain structure and function alterations. Many of these altered brain regions and networks are not just involved in pain processing, but also in other sensory and particularly cognitive tasks. Therefore, the next step is to investigate the relation between brain alterations and pain related cognitive and emotional factors. This review aims at providing an overview of the existing literature on this subject. Pubmed, Web of Science and Embase were searched for original research reports. Twenty eight eligible papers were included, with information on the association of brain alterations with pain catastrophizing, fear‐avoidance, anxiety and depressive symptoms. Methodological quality of eligible papers was checked by two independent researchers. Evidence on the direction of these associations is inconclusive. Pain catastrophizing is related to brain areas involved in pain processing, attention to pain, emotion and motor activity, and to reduced top‐down pain inhibition. In contrast to pain catastrophizing, evidence on anxiety and depressive symptoms shows no clear association with brain characteristics. However, all included cognitive or emotional factors showed significant associations with resting state fMRI data, providing that even at rest the brain reserves a certain activity for these pain‐related factors. Brain changes associated with illness perceptions, pain attention, attitudes and beliefs seem to receive less attention in literature.

Modern pain neuroscience in clinical practice: applied to post-cancer, paediatric and sports-related pain

Highlights • Generalized hypersensitivity in post-cancer, sports-related and pediatric pain.• Rationale for pain education, stress management and cognition targeted exercises.• Need to change from a biomedical or psychosocial to an integrated approach.

Differences Between Women With Traumatic and Idiopathic Chronic Neck Pain and Women Without Neck Pain: Interrelationships Among Disability, Cognitive Deficits, and Central Sensitization

Background To date, a clear differentiation of disability, cognitive deficits, and central sensitization between chronic neck pain of a traumatic nature and that of a nontraumatic nature is lacking. Objective This study aimed to examine differences in disability, cognitive deficits, and central sensitization between women with traumatic and idiopathic (nontraumatic) chronic neck pain and women who were healthy. In addition, interrelationships among these variables were investigated. Design This was a case-control study. Methods Ninety-five women (28 women who were healthy [controls], 35 women with chronic idiopathic neck pain [CINP], and 32 women with chronic whiplash-associated disorders [CWAD] [traumatic]) were enrolled in the study. First, all participants completed standardized questionnaires to investigate pain-related disability and health-related quality of life. Next, cognitive performance was assessed. Finally, pressure pain thresholds and conditioned pain modulation were examined to investigate central sensitization. Results Pain-related disability, reduced health-related quality of life, and cognitive deficits were present in participants with CWAD and, to a significantly lesser extent, in participants with CINP. Local hyperalgesia was demonstrated in participants with CWAD and CINP but not in women who were healthy. However, distant hyperalgesia and decreased conditioned pain modulation efficacy were shown only in participants with CWAD; this result is indicative of the presence of central sensitization. Moderate to strong Spearman correlations (ρ=.456-.701) among disability, cognitive deficits, and hyperalgesia (local and distant) were observed in participants with CWAD. In participants with CINP, only local hyperalgesia and subjective cognitive deficits were moderately (ρ=.463) correlated. Limitations No conclusions about the causality of the observed correlations can be drawn. Conclusions This innovative research revealed important differences between women with CWAD and women with CINP and thus provided evidence of the clinical importance of distinguishing the assessment and rehabilitation approaches for both pain conditions.

Blended-Learning Pain Neuroscience Education for People With Chronic Spinal Pain: Randomized Controlled Multicenter Trial

Background. Available evidence favors the use of pain neuroscience education (PNE) in patients with chronic pain. However, PNE trials are often limited to small sample sizes and, despite the current digital era, the effects of blended‐learning PNE (ie, the combination of online digital media with traditional educational methods) have not yet been investigated. Objective. The study objective was to examine whether blended‐learning PNE is able to improve disability, catastrophizing, kinesiophobia, and illness perceptions. Design. This study was a 2‐center, triple‐blind randomized controlled trial (participants, statistician, and outcome assessor were masked). Setting. The study took place at university hospitals in Ghent and Brussels, Belgium. Participants. Participants were 120 people with nonspecific chronic spinal pain (ie, chronic neck pain and low back pain). Intervention. The intervention was 3 sessions of PNE or biomedically focused back/neck school education (addressing spinal anatomy and physiology). Measurements. Measurements were self‐report questionnaires (Pain Disability Index, Pain Catastrophizing Scale, Tampa Scale for Kinesiophobia, Illness Perception Questionnaire, and Pain Vigilance and Awareness Questionnaire). Results. None of the treatment groups showed a significant change in the perceived disability (Pain Disability Index) due to pain (mean group difference posteducation: 1.84; 95% CI = −2.80 to 6.47). Significant interaction effects were seen for kinesiophobia and several subscales of the Illness Perception Questionnaire, including negative consequences, cyclical time line, and acute/chronic time line. In‐depth analysis revealed that only in the PNE group were these outcomes significantly improved (9% to 17% improvement; 0.37 ≤ Cohen d ≥ 0.86). Limitations. Effect sizes are small to moderate, which might raise the concern of limited clinical utility; however, changes in kinesiophobia exceed the minimal detectable difference. PNE should not be used as the sole treatment modality but should be combined with other treatment strategies. Conclusions. Blended‐learning PNE was able to improve kinesiophobia and illness perceptions in participants with chronic spinal pain. As effect sizes remained small to medium, PNE should not be used as a sole treatment but rather should be used as a key element within a comprehensive active rehabilitation program. Future studies should compare the effects of blended‐learning PNE with offline PNE and should consider cost‐effectiveness.

Convergent validity of the Dutch Central Sensitization Inventory : associations with psychophysical pain measures, quality of life, disability, and pain cognitions in patients with chronic spinal pain

Symptoms of central sensitization (CS) have been described in patients with chronic spinal pain (CSP). Although a gold standard to diagnose CS is lacking, psychophysical pain measures are often used. The Central Sensitization Inventory (CSI) is proposed as an alternative method and indirect tool for the evaluation of CS symptomatology. The aim of the current study was to evaluate the convergent validity of the CSI by investigating the association with psychophysical pain measures and self‐reported measures of current pain intensity, quality of life, disability, and catastrophizing in CSP patients.

Applying contemporary neuroscience in exercise interventions for chronic spinal pain: treatment protocol

Highlights • Treating the central nervous system and psychosocial factors in chronic spinal pain.• This protocol combines pain neuroscience education and cognition targeted exercises.• This paper can be used as guidelines for implementation in clinical practice.

Rehabilitation for patients with myalgic encephalomyelitis/chronic fatigue syndrome: time to extent the boundaries of this field.

Click here to view the Original Article by D. C. W. M. Vos‐Vromans et al.

Sex Differences in Patients with Chronic Pain Following Whiplash Injury: The Role of Depression, Fear, Somatization, Social Support, and Personality Traits

Chronic whiplash‐associated disorders (chronic WAD) cover a large variety of clinical manifestations that can occur after a whiplash injury. Women have an increased risk of developing chronic WAD, and it is suggested that psychosocial factors are related to long‐term pain and functioning following whiplash injury and persistence of chronic pain. This leads to the question whether there are sex differences in psychosocial factors in chronic WAD.