Electrocortical Analysis of Patients with Intercostobrachial Pain Treated with TENS after Breast Cancer Surgery

Resting-state occipital alpha power is associated with treatment outcome in patients with chronic migraine

ABSTRACT

Preventive treatment is crucial for patients with chronic migraine (CM). This study explored the association between resting-state cortical oscillations and 3-month treatment outcome in patients with CM. Treatment-naïve patients with CM were recruited with their demographic data, psychosocial data, and headache profiles as well as the healthy controls (HCs). Resting-state cortical activities were recorded using an electroencephalogram and analysed using source-based and electrode-based spectral power method. The regions of interest were the bilateral primary somatosensory (S1) and visual (V1) cortices. After 3-month treatment with flunarizine, patients with CM were categorized into responders and nonresponders. Demographic, clinical, and electroencephalogram data from 72 patients with CM and 50 HCs were analysed. Elevated anxiety, depression, and stress were observed in patients with CM. Theta power in bilateral S1 and alpha and gamma powers in the right S1 increased in patients with CM. Nonresponders (n = 34) exhibited larger alpha powers in bilateral V1 than those in responders (n = 38). Alpha powers also exhibited significant correlations with changes of monthly headache days. Notably, in responders and nonresponders, occipital alpha powers did not differ at baseline and in the third month. In conclusion, patients with CM who were not responsive to preventive treatment were associated with augmented resting-state occipital alpha activity. Moreover, changes in migraine attack frequency were associated with baseline occipital alpha power. However, the prognostic feature of visual alpha oscillation seems to be inherent because it is not altered by flunarizine treatment. These findings may be useful for developing personalised migraine treatment plans.

Characterising the Features of 381 Clinical Studies Evaluating Transcutaneous Electrical Nerve Stimulation (TENS) for Pain Relief: A Secondary Analysis of the Meta-TENS Study to Improve Future Research

Background and Objectives: Characterising the features of methodologies, clinical attributes and intervention protocols, of studies is valuable to advise directions for research and practice. This article reports the findings of a secondary analysis of the features from studies screened as part of a large systematic review of TENS (the meta-TENS study). Materials and Methods: A descriptive analysis was performed on information associated with methodology, sample populations and intervention protocols from 381 randomised controlled trials (24,532 participants) evaluating TENS delivered at a strong comfortable intensity at the painful site in adults with pain, irrespective of diagnosis. Results: Studies were conducted in 43 countries commonly using parallel group design (n = 334) and one comparator group (n = 231). Mean ± standard deviation (SD) study sample size (64.05 ± 58.29 participants) and TENS group size (27.67 ± 21.90 participants) were small, with only 13 of 381 studies having 100 participants or more in the TENS group. Most TENS interventions were ‘high frequency’ (>10 pps, n = 276) and using 100 Hz (109/353 reports that stated a pulse frequency value). Of 476 comparator groups, 54.2% were active treatments (i.e., analgesic medication(s), exercise, manual therapies and electrophysical agents). Of 202 placebo comparator groups, 155 used a TENS device that did not deliver currents. At least 216 of 383 study groups were able to access other treatments whilst receiving TENS. Only 136 out of 381 reports included a statement about adverse events. Conclusions: Clinical studies on TENS are dominated by small parallel group evaluations of high frequency TENS that are often contaminated by concurrent treatment(s). Study reports tended focus on physiological and clinical implications rather than the veracity of methodology and findings. Previously published criteria for designing and reporting TENS studies were neglected and this should be corrected in future research using insights gleaned from this analysis.

Effects of Transcutaneous Electrical Nerve Stimulation on Mastectomy Pain, Patient Satisfaction, and Patient Outcomes

PURPOSE

Mastectomy is one of the most painful surgical procedures. Postoperative pain guidelines recommend transcutaneous electrical nerve stimulation (TENS) as a reliable non-pharmacological analgesic method. The aim of this study was to investigate the effects of TENS on postoperative pain and outcomes in patients undergoing modified radical mastectomy (MRM).

DESIGN

A single-center, single-blind, prospective, randomized-controlled study.

METHODS

This single-center, single-blind, randomized-controlled study included a total of 80 patients who underwent MRM at general surgery clinic of a tertiary center were included. The pain management of the patient outcomes were evaluated using the Turkish Revised American Pain Society Patient Outcome Questionnaire (APS-POQ-R-TR).

FINDINGS

The pain levels of the intervention group were lower than the control group. There were significant improvements in the patient outcomes such as mobilization, position, sleep, anxiety, and fear in the intervention group.

CONCLUSIONS

Our study results suggest that TENS reduces MRM pain. Thus, TENS can be recommended as a useful analgesic method in MRM.

Pain Management in Breast Surgery: Recommendations of a Multidisciplinary Expert Panel-The American Society of Breast Surgeons

Opioid overdose accounted for more than 47,000 deaths in the United States in 2018. The risk of new persistent opioid use following breast cancer surgery is significant, with up to 10% of patients continuing to fill opioid prescriptions one year after surgery. Over prescription of opioids is far too common. A recent study suggested that up to 80% of patients receiving a prescription for opioids post-operatively do not need them (either do not fill the prescription or do not use the medication). In order to address this important issue, The American Society of Breast Surgeons empaneled an inter-disciplinary committee to develop a consensus statement on pain control for patients undergoing breast surgery. Representatives were nominated by the American College of Surgeons, the Society of Surgical Oncology, The American Society of Plastic Surgeons, and The American Society of Anesthesiologists. A broad literature review followed by a more focused review was performed by the inter-disciplinary panel which was comprised of 14 experts in the fields of breast surgery, anesthesiology, plastic surgery, rehabilitation medicine, and addiction medicine. Through a process of multiple revisions, a consensus was developed, resulting in the outline for decreased opioid use in patients undergoing breast surgery presented in this manuscript. The final document was reviewed and approved by the Board of Directors of the American Society of Breast Surgeons.

Mechanism of Peripheral Nerve Stimulation in Chronic Pain

INTRODUCTION

With the advancement of technology, peripheral nerve stimulation (PNS) has been increasingly used to treat various chronic pain conditions. Its origin is based on the gate control theory postulated by Wall and Melzack in 1965. However, the exact mechanism behind PNS' analgesic effect is largely unknown. In this article, we performed a comprehensive literature review to overview the PNS mechanism of action.

DESIGN

A comprehensive literature review on the mechanism of PNS in chronic pain.

METHODS

Comprehensive review of the available literature on the mechanism of PNS in chronic pain. Data were derived from database searches of PubMed, Scopus, and the Cochrane Library and manual searches of bibliographies and known primary or review articles.

RESULTS

Animal, human, and imaging studies have demonstrated the peripheral and central analgesic mechanisms of PNS by modulating the inflammatory pathways, the autonomic nervous system, the endogenous pain inhibition pathways, and involvement of the cortical and subcortical areas.

CONCLUSIONS

Peripheral nerve stimulation exhibits its neuromodulatory effect both peripherally and centrally. Further understanding of the mechanism of PNS can help guide stimulation approaches and parameters to optimize the use of PNS.

EEG alpha activity increased in response to transcutaneous electrical nervous stimulation in young healthy subjects but not in the healthy elderly

Transcutaneous Electrical Nerve Stimulation (TENS) is used not only in the treatment of pain but also in the examination of sensory functions. With aging, there is decreased sensitivity to somatosensory stimuli. It is essential to examine the effect of TENS application on the sensory functions in the brain by recording the spontaneous electroencephalogram (EEG) activity and the effect of aging on the sensory functions of the brain during the application. The present study aimed to investigate the effect of the application of TENS on the brain’s electrical activity and the effect of aging on the sensory functions of the brain during application of TENS. A total of 15 young (24.2 ± 3.59) and 14 elderly (65.64 ± 4.92) subjects were included in the study. Spontaneous EEG was recorded from 32 channels during TENS application. Power spectrum analysis was performed by Fast Fourier Transform in the alpha frequency band (8–13 Hz) for all subjects. Repeated measures of analysis of variance was used for statistical analysis (p < 0.05). Young subjects had increased alpha power during the TENS application and had gradually increased alpha power by increasing the current intensity of TENS (p = 0.035). Young subjects had higher alpha power than elderly subjects in the occipital and parietal locations (p = 0.073). We can, therefore, conclude that TENS indicated increased alpha activity in young subjects. Young subjects had higher alpha activity than elderly subjects in the occipital and somatosensory areas. To our knowledge, the present study is one of the first studies examining the effect of TENS on spontaneous EEG in healthy subjects. Based on the results of the present study, TENS may be used as an objective method for the examination of sensory impairments, and in the evaluative efficiency of the treatment of pain conditions.

Quantitative Data for Transcutaneous Electrical Nerve Stimulation and Acupuncture Effectiveness in Treatment of Fibromyalgia Syndrome

Aim. To evaluate the effects of acupuncture and transcutaneous electric nerve stimulation (TENS) applications on the quantitative electroencephalography (qEEG) changes and to evaluate their therapeutic effects in patients with fibromyalgia syndrome (FMS). The study included 42 patients with FMS and 21 healthy volunteers. The patients were randomly assigned to two groups (n=21 in each) to undergo either TENS or acupuncture application. In both acupuncture and TENS groups, baseline electroencephalography (EEG) recording was performed for 10 min and, then, TENS or acupuncture was performed for 20 min, followed by another 10 min EEG recording. Baseline qEEG findings of FMS patients in the TENS and acupuncture groups were similar. Delta and theta powers over the frontal region of FMS patients were lower than controls. Theta powers of right posterior region were also lower than controls. In the TENS group, after the treatment, an increase was observed in the alpha power of the left anterior region as well as a decrease in pain scores. In the acupuncture group, an increase was determined in the alpha power of the right and left posterior regions as well as a decrease in pain score after the treatment. The power of low- and moderate-frequency waves on resting EEG was decreased in the patients with FMS. Decreased pain and increased inhibitor activity were found on qEEG after TENS and acupuncture applications. In conclusion, both TENS and acupuncture applications seem to be beneficial in FMS patients.

Does High Frequency Transcutaneous Electrical Nerve Stimulation (TENS) Affect EEG Gamma Band Activity?

BACKGROUND

Transcutaneous electrical nerve stimulation (TENS) is a noninvasive, inexpensive and safe analgesic technique used for relieving acute and chronic pain. However, despite all these advantages, there has been very little research into the therapeutic effects of TENS on brain activity. To the best of our knowledge, there is no evidence on the effect of high frequency TENS on the gamma band activity.

OBJECTIVE

Investigation of the effect of high frequency TENS on the electroencephalographic (EEG) gamma band activity after inducing ischemic pain in healthy volunteers is considered.

MATERIAL AND METHODS

The modified version of Submaximal effort tourniquet test was carried out to induce tonic pain in 15 right-handed healthy volunteers. The high frequency TENS (150µs in duration, frequency of 100 Hz) was applied for 20 minutes. Pain intensity was assessed at using Visual Analog Scale (VAS) in two conditions (after-pain, after-TENS). EEG gamma band activity was recorded by a 19-channel EEG in three conditions (baseline, after-pain and after- TENS). The repeated measure ANOVA and paired-sample T- tests were used for data analysis.

RESULTS

EEG analysis showed an increase in gamma total power after inducing pain as compared to baseline and a decrease after the application of TENS (mean±SD: .043±.029 to .088±.042 to .038±.022 μV² ).The analysis of VAS values demonstrated that the intensity of induced pain (mean±SD: 51.53±9.86) decreased after the application of TENS (mean±SD: 18.66±10.28). All these differences were statistically significant (p<.001).

CONCLUSION

The results of this study revealed that the high frequency TENS can reduce the enhanced gamma band activity after the induction of tonic pain in healthy volunteers. This finding might help as a functional brain biomarker which could be useful for pain treatment, specifically for EEG-based neurofeedback approaches.

Effects of transcutaneous electrical nerve stimulation on chemotherapy-induced peripheral neuropathy symptoms (CIPN): a preliminary case-control study

[Purpose] The aim of this double-blind, randomized and placebo-controlled study is to investigate the effects of Transcutaneous Electrical Nerve Stimulation for reducing the side effects of Chemotherapy-induced Peripheral Neuropathy in cancer patients undergoing chemotherapy with oxaloplatin or paclitaxel. [Subjects and Methods] Twenty-four patients were randomly allocated into two groups: active or placebo stimulation. All patients were assessed for pain, numbness/tingiling, frequency of symptoms, and quality of life. The transcutaneous Electrical Nerve Stimulation device was applied daily with modulating frequencies ranging between 7 Hz and 65 Hz in distal limb regions during three cycles of chemotherapy (45 days). The other stimulation parameters were: pulse duration of 200 μsec, intensity at the highest tolerable level, and increases in intensity when it diminished. [Results] The data showed no difference between active or placebo groups in terms of pain, numbness/tingling, frequency of symptoms or impact on daily life activities. [Conclusion] These results suggest that Transcutaneous Electrical Nerve Stimulation applied in the frequency variation mode was not proven to be effective to improve the symptoms of Chemotherapy-induced Peripheral Neuropathy during chemotherapy cycles. There was no worsening of symptoms in subsequent cycles of the onset of symptoms of the disease.

Reversed cortical over-activity during movement imagination following neurofeedback treatment for central neuropathic pain

OBJECTIVE

One of the brain signatures of the central neuropathic pain (CNP) is the theta band over-activity of wider cortical structures, during imagination of movement. The objective of the study was to investigate whether this over-activity is reversible following the neurofeedback treatment of CNP.

METHODS

Five paraplegic patients with pain in their legs underwent from twenty to forty neurofeedback sessions that significantly reduced their pain. In order to assess their dynamic cortical activity they were asked to imagine movements of all limbs a week before the first and a week after the last neurofeedback session. Using time-frequency analysis we compared EEG activity during imagination of movement before and after the therapy and further compared it with EEG signals of ten paraplegic patients with no pain and a control group of ten able-bodied people.

RESULTS

Neurofeedback treatment resulted in reduced CNP and a wide spread reduction of cortical activity during imagination of movement. The reduction was significant in the alpha and beta band but was largest in the theta band. As a result cortical activity became similar to the activity of other two groups with no pain.

CONCLUSIONS

Reduction of CNP is accompanied by reduced cortical over-activity during movement imagination.

SIGNIFICANCE

Understanding causes and consequences mechanism through which CNP affects cortical activity.

Electroencephalographic Patterns in Chronic Pain: A Systematic Review of the Literature

The main objective of this study is to review and summarize recent findings on electroencephalographic patterns in individuals with chronic pain. We also discuss recent advances in the use of quantitative Electroencephalography (qEEG) for the assessment of pathophysiology and biopsychosocial factors involved in its maintenance over time. Data collection took place from February 2014 to July 2015 in PubMed, SciELO and PEDro databases. Data from cross-sectional studies and longitudinal studies, as well as clinical trials involving chronic pain participants were incorporated into the final analysis. Our primary findings related to chronic pain were an increase of theta and alpha EEG power at rest, and a decrease in the amplitude of evoked potentials after sensory stimulation and cognitive tasks. This review suggests that qEEG could be considered as a simple and objective tool for the study of brain mechanisms involved in chronic pain, as well as for identifying the specific characteristics of chronic pain condition. In addition, results show that qEEG probably is a relevant outcome measure for assessing changes in therapeutic studies.

Characterization of chronic pain in breast cancer survivors using the McGill Pain Questionnaire

The aim of the present study was to characterize pain in breast cancer survivors using the McGill Pain Questionnaire (MPQ). A descriptive, cross-sectional study was conducted with 30 women aged 30-80 years who had been submitted to treatment for breast cancer (surgery and complementary treatment) at least 12 months earlier with reports of pain related to the therapeutic procedures. Pain was characterized using the full-length version of the MPQ, which is made up of 78 descriptors divided into four categories: sensory (ten items), affective (five items), evaluative (one item) and miscellaneous (four items). Two indices were also used to measure pain through the use of the descriptors: the number of words chosen (NWC) and the pain rating index (PRI). The most frequent descriptive terms were "agonizing" (n = 16; 53.3%), "tugging" (n = 15; 50%), "sore" (n = 14; 46.7%), "wretched" (n = 14; 46.7%), "troublesome" (n = 13; 43.3%) and "spreading" (n = 11; 36.7%). The sensory category had the highest PRI value based on the descriptors chosen (mean: 0.41). Women with chronic pain following treatment for breast cancer employed the "agonizing", "tugging" and "sore" descriptors with greatest frequency and rated pain in the sensory category as having the greatest impact.

Effects of two different intensities of transcutaneous electrical nerve stimulation on pain thresholds of contralateral muscles in healthy subjects

[Purpose] This study aimed to investigate the differential effects of high-intensity and low-intensity transcutaneous electrical nerve stimulation on the contralateral side on the pain threshold in healthy subjects. [Subjects and Methods] Twenty-five healthy adults, volunteers received two intensity levels (motor-level, 1.5 times the muscle motor threshold; sensory-level, sensory threshold of the common peroneal nerve), for 30 s on separate days. Pressure pain threshold was recorded on the contralateral tibialis anterior and deltoid muscle before, during, and after stimulation. [Results] Motor-level stimulation significantly increased the pressure pain threshold at both muscle sites, while effects of sensory-level stimulation on pressure pain thresholds were significant only at the deltoid site. The percent change in pressure pain thresholds at both sites was significantly higher during motor-level stimulation. [Conclusion] Motor-level stimulation, applied unilaterally to one leg, produced immediate contralateral diffuse and segmental analgesic effects. This may be of therapeutic benefit in patients for whom transcutaneous electrical nerve stimulation cannot be directly used at the painful site.

Correlations between female breast density and biochemical markers

[Purpose] The aim of this study was to identify biochemical markers related to breast density. The study was performed with 200 patients who received mammography and biochemical marker testing between March 1, 2014 to October 1, 2014. [Subjects and Methods] Following the American College of Radiology, Breast Imaging Reporting and Data System (ACR BI-RADS), breast parenchymal pattern density from mammography was categorized into four grades: grade 1, almost entirely fat; grade 2, fibroglandular densities; grade 3, heterogeneously dense; and grade 4, extremely dense. Regarding biochemical markers, subjects underwent blood and urine tests after a 12-h fast. We analyzed correlations among breast density, general characteristics, and biochemical markers. [Results] Breast density-related factors were age, height, weight, body mass index (BMI), hematocrit, MCH, RDW, AST, ALT, ALP, uric acid, γGT, triglycerides, total cholesterol, HDL-cholesterol, and LDL-cholesterol. [Conclusion] The results can be used as basic and comparative data for the prevention and early control of breast cancer.

Assessing the impact of pain on the life of breast cancer survivors using the Brief Pain Inventory

[Purpose] This study attempted to assess the impact of pain on the life of breast cancer survivors using the Brief Pain Inventory (BPI). [Subjects and Methods] A cross-sectional study was conducted. Participants comprised 30 women, aged 30-80 years, who had received treatment for breast cancer (surgery and complementary treatment) at least 12 months prior to the study and had reported chronic pain related to the treatment procedures. [Results] The highest scores were found for "mood" (median: 5.00 points; first quartile: 1.00 points; third quartile: 7.25 points), "normal work" (median: 5.00 points; first quartile: 0.00 points; third quartile: 8.00 points), and "sleep" (median: 4.50 points, first quartile: 0.00 points, third quartile: 8.00 points). [Conclusion] Pain exerts a negative impact primarily on mood, normal work, and sleep among breast cancer survivors.

Effects of transcutaneous electrical nerve stimulation on pain in patients with spinal cord injury: a randomized controlled trial

[Purpose] To investigate the effects of transcutaneous electrical nerve stimulation (TENS) on pain in patients with spinal cord injury. [Subjects and Methods] Fifty-two spinal cord injury patients with central pain were randomly allocated into two groups TENS and control with 26 subjects per group. The patients in TENS and control groups were treated with TENS and sham TENS for 20 min (three times a week) for 12 consecutive weeks, respectively. The two group’s pain was assessed using visual analog scale (VAS) and the McGill Pain Questionnaire (including pain rating index-total, pain rating index-affective, pain rating index-sensory, present pain intensity, and number of words chosen) before and after the treatment. [Results] After the intervention, we found significant differences in VAS, pain rating index-total, pain rating index-affective, pain rating index-sensory, present pain intensity, and number of words chosen between the TENS group and the control group. [Conclusion] Our results suggest that TENS effectively decreases pain in patients with spinal cord injury.

Analgesic effects of transcutaneous electrical nerve stimulation and interferential current on experimental ischemic pain models: frequencies of 50 hz and 100 hz

[Purpose] This study compared the analgesic effects of transcutaneous electrical nerve stimulation (TENS) and interferential currents (IFC) on induced ischemic pain in healthy volunteers. [Subjects] The subjects were 36 volunteers (18 male, 18 female) without known pathology that could cause pain. Their mean age was 24.5±2.2 years. [Methods] A single-blind and parallel-group method was used. Subjects were randomly allocated to receive each 50 Hz TENS, 50 Hz IFC, 100 Hz TENS, and 100 Hz IFC. This study experimentally induced ischemic pain in otherwise pain-free subjects using a modified version of the submaximal effort tourniquet technique. Subjects completed twelve cycles of the ischemic-induced pain test. The primary outcome measure was the change in self-reported of pain intensity during one of four possible treatments. [Results] There were significant effects for Time, which were attributed to a significant reduction in pain intensity for all groups. There were no significant effects for groups or group-time interaction. The 50 Hz IFC treatment was more comfortable than the other treatments in the present study, and it is likely to be better accepted and tolerated by patients. [Conclusion] We conclude that there were no differences in the analgesic effects of the four treatments under the present experimental conditions. The 50 Hz IFC treatment is more comfortable than the other treatments.