Conceptions of the pain experience: The emergence of multidimensional models and their implications for contemporary clinical practice

Transcutaneous Electrical Nerve Stimulation Reduces Resting Pain in Head and Neck Cancer Patients: A Randomized and Placebo-Controlled Double-Blind Pilot Study

BACKGROUND

Individuals receiving radiation for head and neck cancer (HNC) often develop painful oral mucositis that impairs function, possibly leading to feeding tubes, hospitalization, and treatment delays. Although pharmacologic medications provide some relief, many report inadequate analgesia and adverse effects. Transcutaneous electrical nerve stimulation (TENS) is a safe, nonpharmacologic intervention; it decreases pain and analgesics and improves function, yet no studies examined TENS for HNC.

OBJECTIVE

The aim of this study was to examine the efficacy of TENS for pain and function in HNC patients.

METHODS

This study used a randomized, double-blinded crossover design; participants received 3 TENS treatments during weeks 4 to 6 of radiation: active, placebo, and no TENS over the temporomandibular joint and upper cervical region. Pain (McGill Pain Questionnaire, visual analog scale [VAS] resting and function), function (mouth opening, tongue movement, speaking), fatigue (VAS), and treatment effectiveness (VAS) were assessed before and after TENS at 3 visits.

RESULTS

Resting pain (McGill Pain Questionnaire and VAS) decreased significantly more after active TENS than placebo or no TENS; changes in function and pain with function did not differ between conditions. Active TENS decreased fatigue significantly more than no TENS and was rated as more effective than placebo TENS.

CONCLUSION

Transcutaneous electrical nerve stimulation improves pain in HNC patients receiving radiation but not function or pain with function relative to placebo or no TENS.

IMPLICATIONS FOR PRACTICE

Transcutaneous electrical nerve stimulation may be a viable tool for radiation-induced HNC pain to complement pharmacologic approaches. This nonpharmacologic intervention could decrease the debilitating effects of radiation and analgesics, and improve quality of life. Clinical trials should examine the effects and safety of repeated, daily TENS in HNC patients receiving radiation.

Brain systems at the intersection of chronic pain and self-regulation

Chronic pain is a multidimensional experience with cognitive, affective, and somatosensory components that can be modified by expectations and learning. Individual differences in cognitive and affective processing, as well as contextual aspects of the pain experience, render chronic pain an inherently personal experience. Such individual differences are supported by the heterogeneity of brain representations within and across chronic pain pathologies. In this review, we discuss the complexity of brain representations of pain, and, with respect to this complexity, identify common elements of network-level disruptions in chronic pain. Specifically, we identify prefrontal-limbic circuitry and the default mode network as key elements of functional disruption. We then discuss how these disrupted circuits can be targeted through self-regulation and related cognitive strategies to alleviate chronic pain. We conclude with a proposal for how to develop personalized multivariate models of pain representation in the brain and target them with real-time neurofeedback, so that patients can explore and practice self-regulatory techniques with maximal efficiency.

Myofascial Pain: Mechanisms to Management

More than 100 million adults in the United States have chronic pain conditions, costing more than $500 billion annually in medical care and lost productivity. They are the most common reason for seeking health care, for disability and addiction, and the highest driver of health care costs. Myofascial pain is the most common condition causing chronic pain and can be diagnosed through identifying clinical characteristics and muscle palpation. Management is focused on integrating patient training in changing lifestyle risk factors with evidence-based treatment. Understanding the cause, diagnosis, and management of myopain conditions will help prevent the impact of chronic pain.

Reduced Frontal P3a Amplitude in Migraine Patients during the Pain-Free Period

BACKGROUND AND PURPOSE

Neuropsychological and neuroimaging studies both suggest that frontal lobe dysfunction is present in migraineurs. Since P3a abnormalities manifest in other diseases associated with attention problems, such as attention deficit hyperactivity disorder, we hypothesized that migraine patients have P3a abnormalities, particularly in the frontal region.

METHODS

Event-related potentials were measured using a passive auditory oddball paradigm in 16 female migraineurs (aged 22.9±2.0 years, mean±SD) during the interictal period and in 16 age-matched healthy females (22.6±2.0 years). The amplitudes and latencies were analyzed independently using repeated-measures analysis of variance. Nonparametric statistical testing using a cluster-level randomization method was performed to localize the abnormalities.

RESULTS

The mean P3a amplitude at frontal areas during the third trials was significantly lower in migraineurs (1.06 µV) than in controls (1.69 µV, p=0.026). P3a amplitudes were negatively correlated with the duration of the migraine history (r=-0.618, p=0.014). Cluster-based nonparametric statistical analysis showed that the amplitudes over left frontal areas were significantly lower in migraine patients than in controls.

CONCLUSIONS

A reduced P3a amplitude of migraineurs reflects attentional deficits and frontal dysfunction. The negative correlation between P3a amplitude and the duration of the migraine history suggests that attentional deficits and frontal dysfunction are either the cause or the result of headache.

Myogenous temporomandibular disorders: diagnostic and management considerations

Myogenous temporomandibular disorders (or masticatory myalgia) are characterized by pain and dysfunction that arise from pathologic and functional processes in the masticatory muscles. There are several distinct muscle disorder subtypes in the masticatory system, including myofascial pain, myositis, muscle spasm, and muscle contracture. The major characteristics of masticatory myalgia include pain, muscle tenderness, limited range of motion, and other symptoms (eg, fatigability, stiffness, subjective weakness). Comorbid conditions and complicating factors also are common and are discussed. Management follows with stretching, posture, and relaxation exercises, physical therapy, reduction of contributing factors, and as necessary, muscle injections.

What do ratings on unidimensional pain and emotion scales really mean? A Multidimensional Affect and Pain Survey (MAPS) analysis of cancer patient responses

The purpose of the study was to determine what dimensions of pain predicted scores on numerical rating scales (NRSs) of Pain, Anxiety, Depression, and Health Expectation in cancer patients. Seventy-one patients with intra-abdominal cancer responded to the Multidimensional Affect and Pain Survey (MAPS) and rated their pain and emotion on the NRSs. Scores on the Pain NRS were predicted by 41% of clusters in the MAPS Somatosensory Pain Supercluster, but by 100% of clusters in the Emotional Pain Supercluster, and negatively by 51% of clusters in the Well-Being Supercluster. The Anxiety and Depression NRSs were each predicted by only the Intense Pain cluster in the Somatosensory Pain Supercluster, but by all of clusters in the Emotional Pain Supercluster. The findings indicate that cancer patients' emotional state is a strong co-determinant of their sensory pain ratings. Negative emotional aspects of pain contribute also to scores on the Anxiety, Depression and Health Expectation NRSs.

Management of masticatory myofascial pain

Masticatory myofascial pain is a relatively frequent occurrence in patients seen by the orthodontist. Thus it is important to understand the management of this condition. Treatment is generally directed toward the restoration of a more physiological state in the muscles of mastication and involves medications, appliances, various forms of behavioral modification, as well as the use of muscle exercises and trigger point therapy. This article focuses on the role of the latter modalities in the management of myofascial pain and dysfunction.

Myofascial pain

MFP is a regional muscle pain disorder characterized by localized muscle tenderness and pain and is the most common cause of persistent regional pain. The affected muscles may also display an increased fatiguability, stiffness, subjective weakness, pain on movement and slightly restricted range of motion that is unrelated to joint restriction. MFP is frequently overlooked as a diagnosis because it is often accompanied by signs and symptoms in addition to pain, coincidental pathological conditions, and behavioural and psychosocial problems. Chronic pain characteristics often precede or follow the development of MFP. Evaluation of MFP includes locating the trigger points and muscles involved as well as recognition of the contributing factors. Management of the syndrome naturally follows with muscle exercises, therapy to the trigger points, and reduction of all the contributing factors. The short-term goal is to restore the muscle to normal length and posture and full joint range of motion with exercises and trigger point therapy. The long-term goals include reducing the symptoms and their negative effects while helping the patient return to normal function without the need for future health care. The difficulty in managing MFP lies in the critical need to match the level of complexity of the management programme with the complexity of the patient's situation. Failure to address the entire problem, through a team approach if needed, may lead to failure to resolve the pain and perpetuation of a chronic pain syndrome.

Pain and fear: a bioinformational perspective on responsivity to imagery

Cognitive processing of pain and fear information was examined using a methodology based on the bioinformational theory of emotion. Undergraduate volunteers (n = 48) participated in an imagery assessment procedure involving audio presentation of pain, fear, or pain plus fear experimental scripts. Action and neutral scripts were presented as control stimuli. Heart rate and self-reported affective judgements were assessed. Results indicated that pain scripts were rated more negatively, and were associated with feelings of less dominance than the other experimental scripts. Fear scripts elicited greater heart rate acceleration than either pain or pain plus fear scripts. The direction of physiological and verbal response to pain scripts and fear scripts, however, was very similar, differing only in amplitude; greater heart rate response and more negative ratings were manifested relative to action or neutral scripts.

Cultural perceptions of pain and pain coping among patients and dentists

A combination of qualitative and quantitative methods were developed to describe pain and pain coping perceptions of 25 Chinese, 25 Anglo-Americans and 35 Scandinavians (54 patients and 21 dentists). Results revealed universal dimensions of pain such as time, intensity, location, quality, cause and curability. More culture-specific dimensions included the Chinese concept suantong, a multivariate concept of bone, muscle, joint, tooth and gingival pain. "Real" and "imagined" pains were mostly described by Western subjects, especially dentists; "imagined pain" being the conversion of fear or anxiety into perceived pain. These data indicate that the methods were sensitive to culture as a variable and indicate that ethnicity may play a stronger role in the perceptions of pain description than does professional socialization, but that professional socialization processes may have more influence on the perception of pain coping modes for this sample population.