Relations between experimentally induced tooth pain threshold changes, psychometrics and clinical pain relief following TENS. A retrospective study in patients with long-lasting pain

The Association Between Bodily Functions and Cognitive/Emotional Factors in Patients With Chronic Pain Treated With Neuromodulation: A Systematic Review and Meta-Analyses

OBJECTIVES

To date, pain relief in general continues to be the most prominent outcome measurement in daily routine care and clinical research. Nevertheless, the awareness of a shift toward more functional outcomes and/or emotional and cognitive outcomes has been raised. The interplay between bodily functions (such as pain intensity) and emotional or cognitive factors, however, has not yet been fully elucidated. The aim of this study was to systematically review the evidence for associations between bodily functions and cognitive and emotional factors in patients with chronic pain who are treated with neuromodulation.

MATERIALS AND METHODS

Four data bases were consulted for this systematic literature review: PubMed, Web of Science, Scopus, and Embase. The Downs and Black Checklist (modified) was used to assess the risk of bias. The study protocol was prospectively registered at the International prospective register of systematic reviews (PROSPERO, CRD42021226803). If two or more studies reported correlation coefficients for a specific association, a meta-analysis based on correlation coefficients was performed for that specific association.

RESULTS

The initial data base search identified a total of 1432 studies, of which 19 studies were eventually included in the systematic review. Evidence was found for two associations: 1) a positive correlation between pain intensity and anxiety (r = 0.42; 95% CI, 0.34 to 0.50) and 2) a positive correlation between pain intensity and depression (r = 0.32; 95% CI, 0.10 to 0.51). The association between pain intensity and catastrophizing was not statistically significant (r = 0.23; 95% CI, -0.36 to 0.69).

CONCLUSIONS

On the basis of the associations between pain intensity and anxiety/depression, a biopsychosocial approach might be the most suitable in clinical practice to properly address all aspects of the International Classification of Functioning, Disability, and Health framework in patients who are treated with neuromodulation.

Aspects of Pain, Its Assessment and Evaluation from An Acupuncture Perspective

Pain is a major clinical problem that causes great suffering for the individual and incurs costs for society. Accurate assessment and evaluation of perceived pain is necessary for diagnosis, for choice of treatment, and for the evaluation of treatment efficacy. The assessment of an individual's pain is a challenge since pain is a subjective, multidimensional experience, and assessment is based on the person's own self-report. The results are often varied, possibly due to inter-individual variation, but also in relation to gender and aetiology.

A gold standard for pain assessment is still lacking, but rating scales, questionnaires, and methods derived from psychophysical concepts, such as threshold assessments and perceptual matching, are used. In the evaluation of pain and associated variables, both systematic and individual variation should be taken into account, as should pain-associated symptoms.

Recommendations for pain treatment should be based on the patient's specific needs. Therefore, it is important to assess the level of perceived pain taking individual variation into account. The methods used should preferably have proved to be useful in randomised controlled trials, and analysis of pain assessment should consider its non-metric properties. In the future, the use of studies with a naturalistic protocol together with individual assessment of individual pain responses could increase the internal and external validity.

Transcutaneous electrical nerve stimulation: an effective treatment for pain caused by renal colic in emergency care

PURPOSE

Acute renal colic is one of the most anguishing forms of pain in humans. We hypothesized that TENS is an effective pain treatment in patients with acute renal colic.

MATERIALS AND METHODS

A total of 100 patients with acute flank pain and suspected renal colic consented to participate in our study. Paramedic 1 recorded baseline parameters at the emergency site and at the end of transportation. Paramedic 2 performed TENS in patients randomly assigned to G1 with actual TENS or to G2 with sham TENS. Pain and anxiety were measured using paper based visual analog scales on a scale of 0 to 100 mm.

RESULTS

Of 100 screened patients 73 had renal colic, including 39 in G1 and 34 in G2. There was no significant difference with regard to potentially influencing factors, such as patient age, sex, weight, height, blood pressure and heart rate, pain, nausea and anxiety between the groups before treatment. G1 showed a significant mean pain decrease +/- SD of more than 50% (85.7 +/- 10.5 to 33.3 +/- 16.0 mm, p <0.01). G2 showed no variation in mean pain scores (85.8 +/- 18.0 to 82.6 +/- 14.3 mm). G1 showed changes in the mean anxiety score (69.0 +/- 8.4 to 37.7 +/- 15.1 mm, p <0.01), nausea score (90.7 +/- 9.2 to 44.9 +/- 22.0 mm) and heart rate (92 +/- 10 to 64 +/- 8 bpm), while G2 showed nonsignificant changes.

CONCLUSIONS

This trial shows that local TENS is a rapid and effective treatment for renal colic pain. We found TENS to be a good nondrug therapy under the difficult circumstances of out of hospital rescue.

Gender differences in electrical pain threshold responses to transcutaneous electrical nerve stimulation (TENS)

Gender differences in pain perception have been frequently discussed, but the documented gender-related pain-alleviating effects of non-pharmacological methods are sparse. In this study we aimed to investigate changes in electrical sensory thresholds and electrical pain thresholds, in response to high frequency transcutaneous electrical nerve stimulation, TENS, for 20 min in healthy women (n=29) and men (n=29). The thresholds were assessed pre-, during-, and post-TENS. The pattern of change in thresholds was evaluated with a rank-based statistical method regarding the level of systematic change, expressed as relative position (RP) and additional individual changes, expressed as relative rank variance (RV), with its 95% confidence intervals. Equal levels of systematic changes towards increased electrical sensory thresholds were seen in women and men post-TENS (RP, 0.35; 95% CI, 0.07, 0.63, and RP, 0.36; 95% CI, 0.17, 0.53, respectively). At the same point of time, systematic changes towards increased electrical pain thresholds were only seen in women (RP, 0.43; 95% CI, 0.27, 0.60), while they were unchanged in men (RP, -0.01; 95% CI, -0.13, 0.10). Significant additional individual variations were found in the women's responses of assessed electrical sensory and pain thresholds but not in the men's. It is concluded that both women and men responded with a significant increase of the electrical sensory threshold to high frequency TENS, but only women responded with increase of the electrical pain thresholds. The individual variation of the responses was greater in the women than in the men.

Physical modalities in chronic pain management

The following conclusions can be made based on review of the evidence: There is limited but positive evidence that select physical modalities are effective in managing chronic pain associated with specific conditions experienced by adults and older individuals. Overall, studies have provided the most support for the modality of therapeutic exercise. Different physical modalities have similar magnitudes of effects on chronic pain. Therefore, selection of the most appropriate physical modality may depend on the desired functional outcome for the patient, the underlying impairment, and the patient's preference or prior experience with the modality. Certain patient characteristics may decrease the effectiveness of physical modalities, as has been seen with TENS. These characteristics include depression, high trait anxiety, a powerful others locus of control, obesity, narcotic use, and neuroticism. The effect on pain by various modalities is generally strongest in the short-term period immediately after the intervention series, but effects can last as long as 1 year after treatment (e.g., with massage). Most research has tested the effect of physical modalities on chronic low back pain and knee OA. The effectiveness of physical modalities for other chronic pain conditions needs to be evaluated more completely. Older and younger adults often experience similar effects on their perception of pain from treatment with physical modalities. Therefore, use of these modalities for chronic pain in older adults is appropriate, but special precautions need to be taken. Practitioners applying physical modalities need formal training that includes the risks and precautions for these modalities. If practitioners lack formal training in the use of physical modalities, or if modality use is not within their scope of practice, it is important to consult with and refer patients to members of the team who have this specialized training. Use of a multidisciplinary approach to chronic pain management is of value for all adults and older individuals in particular [79-81]. Historically, physical therapists have been trained to evaluate and treat patients with the range of physical modalities discussed in this article. Although members of the nursing staff traditionally have used some of these modalities (e.g. some forms of heat or cold and massage), increasing numbers of nurses now are being trained to apply more specialized procedures (e.g., TENS). Healthcare professionals must be knowledgeable about the strength of evidence underlying the use of physical modalities for the management of chronic pain. Based on the limited research evidence available (especially related to assistive devices, orthotics, and thermal modalities), it often is difficult to accept or exclude select modalities as having a potential role in chronic pain management for adults and older individuals. Improved research methodologies are needed to address physical modality effectiveness better.

Transcutaneous electrical nerve stimulation (TENS) for chronic pain

BACKGROUND

Transcutaneous electrical nerve stimulation (TENS) is used in a variety of different clinical settings to treat a range of different acute and chronic pain conditions and has become popular with both patients and health professionals.

OBJECTIVES

To evaluate the effectiveness of TENS in chronic pain.

SEARCH STRATEGY

The Cochrane Library, Embase, Medline, CINAHL and The Oxford Pain Database were searched. Reference lists from retrieved reports and reviews were examined. Date of the most recent search: March 1999.

SELECTION CRITERIA

RCTs were eligible if they included the following treatment comparisons: active TENS versus sham TENS controls active TENS versus no treatment controls active TENS versus active TENS controls (for instance High Frequency TENS vs Low Frequency TENS) Studies of patients suffering chronic pain for three months or more which included subjective outcome measures for pain intensity, or pain relief were eligible for evaluation in this review. No restrictions were made to language or sample size. Data from abstracts, letters, or unpublished studies, and studies of TENS in angina, headache and migraine, and dysmenorrhoea were not included.

DATA COLLECTION AND ANALYSIS

Data were extracted and summarised on the following items: patients and details of pain condition, study treatments, study duration, design, methods, subjective pain outcome measures, methodological quality, results for pain outcome measures and adverse effects, and the conclusions made by the authors of the original studies. Extracted data and methodological quality of each report was confirmed by at least three of the reviewers.

MAIN RESULTS

Of 107 reports identified from the searches, 88 were excluded as they did not fulfil the pre-defined entry criteria. Nineteen RCTs (from 18 reports) were evaluated. The included trials varied in terms of design, analgesic outcomes, chronic pain conditions, TENS treatments and overall methodological quality. Studies included single and multiple dose treatment comparisons of TENS. The studies were small. The reporting of the methods used and results for the analgesic outcomes were generally poor. TENS treatments and controls were often poorly defined. Few studies evaluated the long-term analgesic effectiveness of TENS and single dose evaluations of TENS are unhelpful in making clinical decisions of the long-term effectiveness of TENS in the management of chronic pain. Meta-analysis was not possible. Overall in 10 of 15 inactive control studies there was a positive analgesic outcome in favour of the active TENS treatments. For the multiple dose treatment comparison studies only three of seven were considered to be in favour of the active TENS treatments. For the active controlled studies, seven studies made direct comparisons between HFTENS and LFTENS. Five of seven studies could find no difference in terms of analgesic efficacy between HFTENS and LFTENS at any time point.

REVIEWER'S CONCLUSIONS

The results of this review are inconclusive; the published trials do not provide information on the stimulation parameters which are most likely to provide optimum pain relief, nor do they answer questions about long-term effectiveness. Large multi-centre randomised controlled trials of TENS in chronic pain are urgently needed.

Psychological factors in disabling low back pain: causes or consequences?

Low back pain (LBP) is a common problem that is costly in both financial and human terms. The impact of LBP on an individual varies greatly. For some, LBP is a minor inconvenience; but for others LBP is associated with significant disability and with psychosocial dysfunction for the individual and for the family. Whether psychosocial factors are causes or consequences has been the subject of debate. This paper is a review of psychosocial factors associated with disabling LBP. It addresses the question of whether these factors are causes or consequences of the disability due to LBP. Based on this review it was concluded that there is little evidence in support of the concept of a pain-prone personality. Once LBP has occurred, the impact of the LBP on the individual and the family is influenced by the health-beliefs and coping strategies of the individual and the family. Distress appears to be secondary to physical restriction rather than pain, but the distress may aggravate the pain and thus the disability. The paper concludes with a discussion of the impact of health practitioners on pain-related disability.

Pain and the placebo in rehabilitation using TENS and laser

The placebo effect of many health-related treatment is generally acknowledged. This paper discusses the role of the placebo in relation to pain perception and pain control. The theoretical basis of the placebo response is examined, followed by a discussion of the factors influencing the placebo response. Finally, the magnitude of the placebo response is explored specifically in relation to outcome measures and the efficacy of transcutaneous electrical nerve stimulation (TENS) and laser for pain relief.

A comparative study of the effect of high-intensity transcutaneous nerve stimulation and oral naproxen on intrauterine pressure and menstrual pain in patients with primary dysmenorrhea

OBJECTIVE

Our purpose was to compare the effects of high-intensity transcutaneous electrical nerve stimulation and oral naproxen (500 mg) on intrauterine pressure and menstrual pain.

STUDY DESIGN

An open, randomized crossover study was performed on 12 women with primary dysmenorrhea. Intrauterine pressure was recorded with a microtransducer catheter, and the pain score was assessed by a visual analog scale.

RESULTS

Before treatment all patients displayed signs of uterine hyperactivity as judged by a high resting pressure (7.5 +/- 0.4 kPa), high active pressure (24.0 +/- 0.8 kPa), and a high frequency of pressure cycles (13.3 +/- 0.5 contractions per 0.5 hour). Oral administration of naproxen suppressed (p < 0.01) all uterine activity parameters. Treatment with transcutaneous electrical nerve stimulation induced a prompt onset of pain relief in a strictly segmental manner, but there were no significant changes in uterine activity. The pain score was significantly reduced (p < 0.001) from 30 to 60 minutes after treatment with transcutaneous electrical nerve stimulation and from 19 to 120 minutes after naproxen administration.

CONCLUSIONS

Treatment with transcutaneous electrical nerve stimulation induced a prompt onset of pain relief without any significant changes in uterine activity. Possible mechanisms for the pain relief, decreased uterine ischemia or decreased activity in the pain transmission system at spinal or supraspinal levels, are discussed.

A critical review of dimension-specific measures of health-related quality of life in cross-cultural research

This article reviews six dimension-specific health-related quality of life (HRQL) measures which have been used cross-culturally. The instruments reviewed are: the Beck Depression Inventory (BDI); the McGill Pain Questionnaire (MPQ); the Center for Epidemiologic Studies--Depression (CES-D); the Zung Self-Rating Depression Scale (SDS); the General Health Questionnaire (GHQ); and the Psychological General Well-Being Index (PGWB). These instruments primarily represent the psychological or emotional dimension of HRQL, and are scales that were developed and validated in the USA, Canada or the UK. The review of specific studies for each of the six instruments was not meant to be exhaustive, but rather to give an indication of the ways in which the instruments have been assessed or used in various countries. The focus throughout this article is on the psychometric properties (reliability, validity and responsiveness) of these scales in different cultures, as well as the processes used to translate the instruments from English into another language. Implications of the results of this review for cross-cultural use of dimension-specific HRQL instruments are drawn.