Recognition of central sensitization in patients with musculoskeletal pain: Application of pain neurophysiology in manual therapy practice

Short-term effects of a manual therapy protocol on pain, physical function, quality of sleep, depressive symptoms, and pressure sensitivity in women and men with fibromyalgia syndrome: a randomized controlled trial

OBJECTIVE

To investigate the therapeutic effects of a manual therapy protocol for improving pain, function, pressure pain thresholds (PPT), quality of sleep, and depressive symptoms in women and men with fibromyalgia syndrome (FMS).

MATERIALS AND METHODS

Eighty-nine patients were randomly assigned to experimental or control group. The experimental group (24 female, 21 male) received 5 sessions of manual therapy and the control group (24 female, 21 male) did not receive any intervention. PPT, pain, impact of FMS symptoms, quality of sleep, and depressive symptoms were assessed in both groups at baseline and after 48 hours of the last intervention in the experimental group.

RESULTS

The analysis of covariance found significant Group×Time×Sex interactions for McGill PPI and Center for Epidemiologic Studies Depressive Symptoms Scale (P<0.01) was also found: men exhibited a larger effect size for depressive symptoms than women, whereas women exhibited a greater effect size than men in the McGill PPI. A significant Group×Time×Sex interaction for PPT over suboccipital, upper trapezius, supraspinatus, second rib, gluteal region, and tibialis anterior muscle was also found: men included in the experimental group experienced significant greater improvements in PPT as compared with women with FMS in the experimental group.

CONCLUSIONS

Manual therapy protocol was effective for improving pain intensity, widespread pressure pain sensitivity, impact of FMS symptoms, sleep quality, and depressive symptoms. In addition, sex differences were observed in response to treatment: women and men get similar improvements in quality of sleep and tender point count, whereas women showed a greater reduction in pain and impact of FMS symptoms than men, but men reported higher decreases in depressive symptoms and pressure hypersensitivity than women.

Brain-derived neurotrophic factor as a driving force behind neuroplasticity in neuropathic and central sensitization pain: a new therapeutic target?

INTRODUCTION

Central sensitization is a form of maladaptive neuroplasticity underlying many chronic pain disorders, including neuropathic pain, fibromyalgia, whiplash, headache, chronic pelvic pain syndrome and some forms of osteoarthritis, low back pain, epicondylitis, shoulder pain and cancer pain. Brain-derived neurotrophic factor (BDNF) is a driving force behind neuroplasticity, and it is therefore crucial for neural maintenance and repair. However, BDNF also contributes to sensitization of pain pathways, making it an interesting novel therapeutic target.

AREAS COVERED

An overview of BDNF's sensitizing capacity at every level of the pain pathways is presented, including the peripheral nociceptors, dorsal root ganglia, spinal dorsal horn neurons, and brain descending inhibitory and facilitatory pathways. This is followed by the presentation of several potential therapeutic options, ranging from indirect influencing of BDNF levels (using exercise therapy, anti-inflammatory drugs, melatonin, repetitive transcranial magnetic stimulation) to more specific targeting of BDNF's receptors and signaling pathways (blocking the proteinase-activated receptors 2-NK-κβ signaling pathway, administration of phencyclidine for antagonizing NMDA receptors, or blockade of the adenosine A2A receptor).

EXPERT OPINION

This section focuses on combining pharmacotherapy with multimodal rehabilitation for balancing the deleterious and therapeutic effects of BNDF treatment in chronic pain patients, as well as accounting for the complex and biopsychosocial nature of chronic pain.

The current state of physical therapy pain curricula in the United States: a faculty survey

Insufficient pain education is problematic across the health care spectrum. Recent educational advancements have been made to combat the deficits in pain education to ensure that health care professionals are proficient in assessing and managing pain. The purpose of this survey was to determine the extent of pain education in current Doctorate of Physical Therapy schools in the United States, including how pain is incorporated into the curriculum, the amount of time spent teaching about pain, and the resources used to teach about pain. The survey consisted of 10 questions in the following subject areas: basic science mechanisms and concepts about pain, pain assessment, pain management, and adequacy of pain curriculum. The overall response was 77% (167/216) for the first series of responses of the survey (Question 1), whereas 62% completed the entire survey (Questions 2-10). The average contact hours teaching about pain was 31 ± 1.8 (mean ± standard error of the mean) with a range of 5 to 115 hours. The majority of schools that responded covered the science of pain, assessment, and management. Less than 50% of respondents were aware of the Institute of Medicine report on pain or the International Association for the Study of Pain guidelines for physical therapy pain education. Only 61% of respondents believed that their students received adequate education in pain management. Thus, this survey demonstrated how pain education is incorporated into physical therapy schools and highlighted areas for improvement such as awareness of recent educational advancements.

PERSPECTIVE

This article demonstrates how pain education is incorporated into physical therapy curricula within accredited programs. Understanding the current structure of pain education in health professional curriculum can serve as a basis to determine if recent publications of guidelines and competencies impact education.

Experimental pain responses support peripheral and central sensitization in patients with unilateral shoulder pain

OBJECTIVE

The aims of this study were to (1) examine the pattern of experimental pain responses in the affected and nonaffected extremities in patients with shoulder pain and (2) explore the intraindividual association between sensitization states derived from experimental pain testing.

METHODS

Experimental pain responses from 58 patients with shoulder pain (17 women, aged 18 to 52 y) were compared with those from 56 age-matched and sex-matched pain-free volunteers (16 women, aged 21 to 58 y). Experimental pain responses included pressure pain threshold (PPT), thermal pain threshold and tolerance, and suprathreshold heat pain response. Comparisons were made between the affected and nonaffected extremities of clinical participants and the average response of extremities in control participants. Peripheral and central sensitization indexes were computed for clinical participants using standardized scores and percentile cutoffs on the basis of the data from the control sample. Experimental pain responses in clinical participants observed beyond the 25th and 75th percentile of control sample responses were used for investigation of intraindividual association of sensitization states.

RESULTS

PPT at the acromion and masseter on the affected side of clinical participants were diminished compared with that on their nonaffected side (P<0.015). Bilateral sensitivity in clinical participants was noted for PPT at the acromion and suprathreshold heat pain response (P<0.015). Peripheral and central sensitization indexes demonstrated that individuals with shoulder pain present with variable patterns of peripheral and central sensitization.

CONCLUSIONS

Collectively, experimental pain responses supported peripheral and central sensitization in response to pressure and thermal stimuli. No clear association was made between individuals exhibiting peripheral or central sensitization, thus suggesting heterogeneity in pain processing in this clinical population.

Myofascial trigger points: peripheral or central phenomenon?

Trigger points (TrP) are hyperirritable spots in a taut band of a skeletal muscle, which usually have referred pain. There is controversy over whether TrP are a peripheral or central nervous system phenomenon. Referred pain, the most characteristic sign of TrP, is a central phenomenon initiated and activated by peripheral sensitization, whereby the peripheral nociceptive input from the muscle can sensitize dorsal horn neurons that were previously silent. TrP are a peripheral source of nociception, and act as ongoing nociceptive stimuli contributing to pain propagation and widespread pain. Several studies support the hypothesis that TrP can induce central sensitization, and appropriate TrP treatment reduces central sensitization. In contrast, preliminary evidence suggests that central sensitization can also promote TrP activity, although further studies are needed. Proper TrP management may prevent and reverse the development of pain propagation in chronic pain conditions, because inactivation of TrP attenuates central sensitization.

Clinical reasoning for manual therapy management of tension type and cervicogenic headache

In recent years, there has been an increasing knowledge in the pathogenesis and better management of chronic headaches. Current scientific evidence supports the role of manual therapies in the management of tension type and cervicogenic headache, but the results are still conflicting. These inconsistent results can be related to the fact that maybe not all manual therapies are appropriate for all types of headaches; or maybe not all patients with headache will benefit from manual therapies. There are preliminary data suggesting that patients with a lower degree of sensitization will benefit to a greater extent from manual therapies, although more studies are needed. In fact, there is evidence demonstrating the presence of peripheral and central sensitization in chronic headaches, particularly in tension type. Clinical management of patients with headache needs to extend beyond local tissue-based pathology, to incorporate strategies directed at normalizing central nervous system sensitivity. In such a scenario, this paper exposes some examples of manual therapies for tension type and cervicogenic headache, based on a nociceptive pain rationale, for modulating central nervous system hypersensitivity: trigger point therapy, joint mobilization, joint manipulation, exercise, and cognitive pain approaches.

A systematic review investigating the relationship between efficacy and stimulation parameters when using transcutaneous electrical nerve stimulation after knee arthroplasty

OBJECTIVE

To evaluate the clinical efficacy of transcutaneous electric nerve stimulation in the treatment of postoperative knee arthroplasty pain and to relate these results to the stimulation parameters used.

DATA SOURCES

PubMed, Pedro and Web of Knowledge were systematically screened for studies investigating effects of transcutaneous electric nerve stimulation on postoperative knee arthroplasty pain.

REVIEW METHODS

Studies were screened for their methodological and therapeutical quality. We appraised the influence of the stimulation settings used and indicated whether or not a neurophysiological and/or mechanistic rationale was given for these stimulation settings.

RESULTS

A total of 5 articles met the inclusion criteria. In total, 347 patients were investigated. The number of patients who received some form of transcutaneous electric nerve stimulation was 117, and 54 patients received sham transcutaneous electric nerve stimulation. Pain was the primary outcome in all studies. The stimulation settings used in the studies (n = 2) that reported significant effects differed from the others as they implemented a submaximal stimulation intensity. Stimulation parameters were heterogeneous, and only one study provided a rationale for them.

CONCLUSION

This review reveals that an effect of transcutaneous electric nerve stimulation might have been missed due to low methodological and therapeutical quality. Justifying the choice of transcutaneous electric nerve stimulation parameters may improve therapeutical quality.

A modern neuroscience approach to chronic spinal pain: combining pain neuroscience education with cognition-targeted motor control training

Chronic spinal pain (CSP) is a severely disabling disorder, including nontraumatic chronic low back and neck pain, failed back surgery, and chronic whiplash-associated disorders. Much of the current therapy is focused on input mechanisms (treating peripheral elements such as muscles and joints) and output mechanisms (addressing motor control), while there is less attention to processing (central) mechanisms. In addition to the compelling evidence for impaired motor control of spinal muscles in patients with CSP, there is increasing evidence that central mechanisms (ie, hyperexcitability of the central nervous system and brain abnormalities) play a role in CSP. Hence, treatments for CSP should address not only peripheral dysfunctions but also the brain. Therefore, a modern neuroscience approach, comprising therapeutic pain neuroscience education followed by cognition-targeted motor control training, is proposed. This perspective article explains why and how such an approach to CSP can be applied in physical therapist practice.

Can recovery of peripheral muscle function predict cognitive task performance in chronic fatigue syndrome with and without fibromyalgia?

BACKGROUND

Both good physical and cognitive functioning have a positive influence on the execution of activities of daily living. Patients with chronic fatigue syndrome (CFS) as well as patients with fibromyalgia have marked cognitive deficits. Furthermore, a good physical and functional health status may have a positive impact on a variety of cognitive skills-a link that has been observed in young and old individuals who are healthy, although evidence is limited in patients with CFS.

OBJECTIVE

The purpose of this study was to examine whether recovery of upper limb muscle function could be a significant predictor of cognitive performance in patients with CFS and in patients with CFS and comorbid fibromyalgia. Furthermore, this study determined whether cognitive performance is different between these patient groups.

DESIGN

A case-control design was used.

METHODS

Seventy-eight participants were included in the study: 18 patients with CFS only (CFS group), 30 patients with CFS and comorbid fibromyalgia (CFS+FM group), and 30 individuals who were healthy and inactive (control group) were studied. Participants first completed 3 performance-based cognitive tests designed to assess selective and sustained attention, cognitive inhibition, and working memory capacity. Seven days later, they performed a fatiguing upper limb exercise test, with subsequent recovery measures.

RESULTS

Recovery of upper limb muscle function was found to be a significant predictor of cognitive performance in patients with CFS. Participants in the CFS+FM group but not those in the CFS group showed significantly decreased cognitive performance compared with the control group.

LIMITATIONS

The cross-sectional nature of this study does not allow for inferences of causation.

CONCLUSIONS

The results suggest that better physical health status could predict better mental health in patients with CFS. Furthermore, they underline disease heterogeneity, suggesting that reducing this factor in future research is important to better understand and uncover mechanisms regarding the nature of diverse impairments in these patients.

Physiologic effects of dry needling

During the past decades, worldwide clinical and scientific interest in dry needling (DN) therapy has grown exponentially. Various clinical effects have been credited to dry needling, but rigorous evidence about its potential physiological mechanisms of actions and effects is still lacking. Research identifying these exact mechanisms of dry needling action is sparse and studies performed in an acupuncture setting do not necessarily apply to DN. The studies of potential effects of DN are reviewed in reference to the different aspects involved in the pathophysiology of myofascial triggerpoints: the taut band, local ischemia and hypoxia, peripheral and central sensitization. This article aims to provide the physiotherapist with a greater understanding of the contemporary data available: what effects could be attributed to dry needling and what are their potential underlying mechanisms of action, and also indicate some directions at which future research could be aimed to fill current voids.

Recovery of upper limb muscle function in chronic fatigue syndrome with and without fibromyalgia

BACKGROUND

Chronic fatigue syndrome (CFS) patients frequently complain of muscle fatigue and abnormally slow recovery, especially of the upper limb muscles during and after activities of daily living. Furthermore, disease heterogeneity has not yet been studied in relation to recovery of muscle function in CFS. Here, we examine recovery of upper limb muscle function from a fatiguing exercise in CFS patients with (CFS+FM) and without (CFS-only) comorbid fibromyalgia and compare their results with a matched inactive control group.

DESIGN

In this case-control study, 18 CFS-only patients, 30 CFS+FM patients and 30 healthy inactive controls performed a fatiguing upper limb exercise test with subsequent recovery measures.

RESULTS

There was no significant difference among the three groups for maximal handgrip strength of the non-dominant hand. A significant worse recovery of upper limb muscle function was found in the CFS+FM, but not in de CFS-only group compared with the controls (P < 0·05).

CONCLUSIONS

This study reveals, for the first time, delayed recovery of upper limb muscle function in CFS+FM, but not in CFS-only patients. The results underline that CFS is a heterogeneous disorder suggesting that reducing the heterogeneity of the disorder in future research is important to make progress towards a better understanding and uncovering of mechanisms regarding the nature of divers impairments in these patients.

The use of functional and traditional mobilization interventions in a patient with chronic thoracic pain: a case report

There is little information in the literature regarding the efficacy of spinal manual therapy (SMT) interventions for patients with chronic thoracic spinal pain. In addition, information regarding the clinical decision-making associated with the application of SMT for this patient population is deficient. The purpose of this case report is to present the rationale for and results of applying specific SMT interventions on a patient with chronic spinal pain. A 51-year-old female with 9 months of significant thoracic, chest, sternal, and left shoulder pain was managed with both mobilization with movement and spinal manipulative procedures. The report offers insight into the decisions that guided the selection of these SMT techniques in this case. The outcome provides preliminary support for using these specific SMT procedures in patients with chronic thoracic spinal pain.

Pain treatment for patients with osteoarthritis and central sensitization

Osteoarthritis is one of the most frequent, disabling, and costly pathologies of modern society. Among the main aims of osteoarthritis management are pain control and functional ability improvement. The exact cause of osteoarthritis pain remains unclear. In addition to the pathological changes in articular structures, changes in central pain processing or central sensitization appear to be involved in osteoarthritis pain. The latter calls for a broader approach to the management of patients with osteoarthritis. Yet, the scientific literature offers scant information addressing the treatment of central sensitization, specifically in patients with osteoarthritis. Interventions such as cognitive-behavioral therapy and neuroscience education potentially target cognitive-emotional sensitization (and descending facilitation), and centrally acting drugs and exercise therapy can improve endogenous analgesia (descending inhibition) in patients with osteoarthritis. Future studies should assess these new treatment avenues.

Body mass index and musculoskeletal pain: is there a connection?

Background

Back pain is one of the most common complaints that patients report to physicians and two-thirds of the population has an elevated body mass index (BMI), indicating they are either overweight or obese. It was once assumed that extra body weight would stress the low back and lead to pain, however, researchers have reported inconsistencies association between body weight and back pain. In contrast, more recent studies do indicate that an elevated BMI is associated with back pain and other musculoskeletal pain syndromes due to the presence of a chronic systemic inflammatory state, suggesting that the relationship between BMI and musculoskeletal pains be considered in more detail.

Objective

To describe how an elevated BMI can be associated with chronic systemic inflammation and pain expression. To outline measurable risk factors for chronic inflammation that can be used in clinical practice and discuss basic treatment considerations.

Discussion

Adiposopathy, or “sick fat” syndrome, is a term that refers to an elevated BMI that is associated with a chronic systemic inflammatory state most commonly referred to as the metabolic syndrome. The best available evidence suggests that the presence of adiposopathy determines if an elevated BMI will contribute to musculoskeletal pain expression. It is not uncommon for physicians to fail to identify the presence of adiposopathy/metabolic syndrome.

Conclusion

Patients with an elevated BMI should be further examined to identify inflammatory factors associated with adiposopathy, such as the metabolic syndrome, which may be promoting back pain and other musculoskeletal pain syndromes.

Chronic pain in leprosy: new aspects to be considered

Leprosy is still considered to be endemic in several developing countries, such as India and Brazil. Infection with Mycobacterium leprae leads to chronic granulomatous inflammation in skin and peripheral nerves that can lead to sensory, motor and autonomic impairments. Since the disease causes severe sensory loss, little attention has been given to pain in leprosy. However, chronic pain in leprosy is being increasingly recognized as an important late complication of leprosy. This article discusses the assessment of pain in leprosy and suggests factors that can contribute to the chronicity. We also consider pain as a multiple system output, bringing the possibility of new treatment options for chronic pain in leprosy.

Subgroups based on thermal and pressure pain thresholds in women with chronic whiplash display differences in clinical presentation - an explorative study

PURPOSE

To investigate the presence of subgroups in chronic whiplash-associated disorders (WAD) based on pain thresholds for pressure (PPT), cold (CPT), and heat (HPT) and to compare these subgroups with respect to symptomatology, disability, and health aspects.

METHODS

Two groups of female subjects - patients with chronic WAD (n = 28) and healthy controls (CON; n = 29) - were investigated. Quantitative sensory testing (QST) for thermal thresholds and algometry for PPT at four sites in the body (over the trapezius and tibialis anterior bilaterally) were determined. Habitual pain intensities, psychological strain, disability, and health aspects were registered using a questionnaire.

RESULTS

A CLUSTER ANALYSIS BASED ON PPT, CPT, AND HPT IDENTIFIED TWO SUBGROUPS OF CHRONIC WAD: one sensitive subgroup (s-WAD; n = 21), and one less sensitive subgroup (ls-WAD; n = 6). S-WAD displayed widespread hyperalgesia, whereas ls-WAD had localized hyperalgesia in the neck area, with tendencies to supernormal values in remote areas of the body. Generally, s-WAD had a significantly worse situation than the CON with respect to symptomatology, disability, and health aspects. The ls-WAD group was intermediary between s-WAD and CON in these aspects.

CONCLUSION

Different explanations, eg, severity of the pain condition per se, etiological factors, and pre-trauma differences in pain sensitivity, may exist for the differences in pain thresholds between the two subgroups. Future research should investigate the role of pain thresholds in the chronic stage to determine the efficacy of treatment interventions.