The Development of the MedEx IMPACT Intervention: A Patient-Centered, Evidenced-Based and Theoretically-Informed Physical Activity Behavior Change Intervention for Individuals Living With and Beyond Cancer.

Regular physical activity (PA) can address many of the negative side effects experienced by individuals following cancer treatment and support the optimization of physical and psychosocial well-being. However, many survivors of cancer are not sufficiently active to achieve these health benefits. The purpose of this study was to describe the development of a physical activity behavior change (PABC) intervention, MedEx IMPACT (IMprove Physical Activity after Cancer Treatment), which aims to increase cancer survivors' PA levels. A review of the literature and focus groups with survivors of cancer were conducted in order to generate recommendations to inform the intervention development process. This process was guided and informed by: (1) the Medical Research Council's (MRC) framework for the development, evaluation, and implementation of complex interventions, (2) the Behaviour Change Wheel (BCW), and (3) the Theoretical Domains Framework (TDF). Recommendations for strategies to support habitual PA and adherence to community-based exercise programs, generated by survivors of cancer who participated in 7 focus groups (n = 41), were synthesized with 13 statements of findings that were generated from 10 studies included within the review of the literature. Detailed mapping exercises are presented which outline the link between these sources, the MRC framework, the BCW and TDF, and the intervention content. MedEx IMPACT is the first PABC intervention for survivors of cancer to be developed through the application of the MRC framework, BCW, and TDF. The next phase in this research is to test the acceptability and effectiveness of MedEx IMPACT.

What predicts emotional response in men awaiting prostate biopsy?

BACKGROUND: Incidence of prostate cancer is increasing as opportunistic screening becomes widespread and life expectancy rises. Despite screening availability, research reveals conflicting results on medical outcomes, for example, disease specific mortality. However the gold standard in early diagnosis of potentially curable organ confined prostate cancer is transrectal ultrasound-guided systematic prostate biopsy (TRUS-BX). While focus has been given to medical sequalae there is a paucity of research on the psychological impact of biopsy. Awaiting biopsy may be inherently stressful but no studies to date, have assessed men's perception of stress and its impact on emotional response. This study, therefore, examines the role of stress and also personal resources namely, self-efficacy and sense of coherence in emotional adjustment in men awaiting a prostate biopsy. METHODS: Men attending a Rapid Access Prostate Cancer Clinic for a transrectal prostate biopsy (N = 114) participated in the study. They completed self report questionnaires on perceived stress (PSS), generalised self-efficacy (GSES), and sense of coherence (SOC). Adjustment was measured by the Profile of Mood States (POMS-B) which assesses tension, depression, anger, fatigue, confusion and vigour. RESULTS: Hierarchical regression analyses demonstrated that the set of predictors accounted for 17%-34% of variance across six mood states and predicted 46% of total mood disturbance. Perceived stress explained variance on all domains (11%-26%) with high stress linked to poor functioning. CONCLUSION: Perceived stress was the strongest and most consistent predictor of emotional adjustment. This is an important finding as stress appraisal has not been examined previously in this context and suggests that stress management is an important target to enhance emotional wellbeing of men attending for a prostate biopsy.

Postprandial effect of dietary fat quantity and quality on arterial stiffness and wave reflection: a randomised controlled trial.

BACKGROUND: Arterial stiffness is a component of vascular function and an established risk factor for cardiovascular disease. There is a lack of conclusive evidence on the effect of a meal rich in monounsaturated fat (MUFA) compared with an isoenergetic meal rich in saturated fat (SFA) on postprandial vascular function and specifically on arterial stiffness. METHODS: Twenty healthy, non-smoking males (BMI 24 ± 2 kg/m2; age 37.7 ± 14.4 y) participated in this single-blind, randomised, cross-over dietary intervention study. Each subject was randomised to receive a high-fat test-meal (3 MJ; 56 ± 2 g fat) at breakfast on 2 separate occasions, one rich in oleic acid (MUFA-meal) and one rich in palmitic acid (SFA-meal), and the meals were isoenergetic. Blood pressure (BP), arterial stiffness (PWV) and arterial wave reflection (augmentation index, AIx) were measured using applanation tonometry at baseline and every 30 minutes up to 4 hours after the ingestion of the test-meals. RESULTS: All subjects completed both arms of the dietary intervention. There was no significant difference in BP parameters, PWV or AIx at baseline between the two treatments (P > 0.05). There was a significant increase in brachial and aortic BP, mean arterial pressure (MAP), heart rate and PVW (time, P < 0.05) over the four hours after consumption of the fat-rich test-meal although the increase in PWV was no longer significant when adjusted for the increase in MAP. There was no difference in PWV between the two treatments (treatment*time, P > 0.05). There was a significant reduction in AIx (time, P < 0.05) over the four hour postprandial period although this was no longer significant when adjusted for the increase in heart rate and MAP (time, P > 0.05). There was no difference in AIx between the two treatments (treatment*time, P > 0.05). However, the reduction in heart rate corrected augmentation index (AIx75) was significant when corrected for the increase in MAP (time, P < 0.01) with no differential effect of the treatments (treatment*time, P > 0.05). CONCLUSIONS: This study has demonstrated a BP dependent increase in PWV and a decrease in arterial wave reflection in the four hour period in response to a high-fat meal. There was no evidence however that replacement of some of the SFA with MUFA had a differential effect on these parameters. The study highlights the need for further research to understand the effects of the substitution of SFA with MUFA on non-serum, new and emerging risk factors for CVD such as arterial stiffness.

A comparison of the hypoalgesic effects of transcutaneous electrical nerve stimulation (TENS) and non-invasive interactive neurostimulation (InterX(®)) on experimentally induced blunt pressure pain using healthy human volunteers.

OBJECTIVES: Non-invasive interactive neurostimulation (InterX(®)) delivers high amplitude electrical pulsed currents at points of low impedance on the skin. This study compared the hypoalgesic effect of non-invasive interactive neurostimulation with transcutaneous electrical nerve stimulation (TENS). MATERIALS AND METHODS: A repeated measures parallel group study on healthy human volunteers randomized to receive strong non-painful TENS or non-invasive interactive neurostimulation for 21 min on the forearm (N= 10/group). Pressure algometry was used to determine blunt pressure pain threshold at baseline, 10, and 20 min during stimulation, and 5 min post stimulation. RESULTS: Low impedance sites were found in half of the participants receiving non-invasive interactive neurostimulation. ANOVA found no effects for intervention (p= 0.923), time × intervention interaction (p= 0.21), or time (p= 0.094). CONCLUSIONS: Given the limited power of this study, we show that there were no significant differences in hypoalgesia between non-invasive interactive neurostimulation and TENS. Unlike our previous studies we also failed to detect a change pain threshold during TENS. Nevertheless, our findings can be used to inform the design of an appropriately powered study on pain patients.

Transcutaneous electrical nerve stimulation for acute pain.

BACKGROUND: Transcutaneous Electrical Nerve Stimulation (TENS) is a non-pharmacological agent, based on delivering low voltage electrical currents to the skin. TENS is used for the treatment of a variety of pain conditions. OBJECTIVES: To assess the analgesic effectiveness of TENS for acute pain in adults to see if it had any clear analgesic effect in its own right. SEARCH STRATEGY: The following databases were searched: Cochrane Pain, Palliative and Supportive Care Group Specialised Register; the Cochrane Central Register of Controlled Trials, CENTRAL (in The Cochrane Library); MEDLINE; EMBASE; CINAHL; AMED; PEDro; OTseeker; OpenSIGLE; and, reference lists of included studies. The most recent search was undertaken in August 2008. SELECTION CRITERIA: Randomised controlled trials (RCTs) of adults with acute pain (less than 12 weeks) were included if they examined TENS given as a sole treatment and assessed pain with subjective pain scales. Studies were eligible if they compared TENS to placebo TENS, no treatment controls, pharmacological interventions or non-pharmacological interventions. Studies on experimental pain, case reports, clinical observations, letters, abstracts or reviews were excluded. Studies on TENS and labour pain, pain due to dental procedures and primary dysmenorrhoea were excluded. Studies where TENS was given with another treatment as part of the formal study design were also excluded. No restrictions were made regarding language. DATA COLLECTION AND ANALYSIS: Two authors independently assessed trial eligibility and extracted data. Data were extracted on the following: types of participants and pain condition, study design and methods, treatment parameters, adverse effects, and outcome measures. Study authors were contacted for additional information if necessary. MAIN RESULTS: Of 1479 studies identified in the search, 132 were identified as relevant. Of these, 116 were excluded; the vast majority of these were excluded due to TENS being given with another treatment. Four studies were categorised as awaiting classification as the information provided in the full text failed to clarify their eligibility. Twelve RCTs involving 919 participants at entry were included. The types of acute pain conditions included procedural pain, e.g. cervical laser treatment, venipuncture, screening flexible sigmoidoscopy and non-procedural pain, e.g. postpartum uterine contractions, rib fractures. It was not possible to perform a meta-analysis due to insufficient data. AUTHORS' CONCLUSIONS: Due to insufficient extractable data in the studies included in this review, we are unable to make any definitive conclusions about the effectiveness of TENS as an isolated treatment for acute pain in adults.

The development and codesign of the PATHway intervention: a theory-driven eHealth platform for the self-management of cardiovascular disease.

Cardiovascular diseases (CVDs) are a leading cause of premature death worldwide. International guidelines recommend routine delivery of all phases of cardiac rehabilitation (CR). Uptake of traditional CR remains suboptimal, as attendance at formal hospital-based CR programs is low, with community-based CR rates and individual long-term exercise maintenance even lower. Home-based CR programs have been shown to be equally effective in clinical and health-related quality of life outcomes and yet are not readily available. The aim of the current study was to develop the PATHway intervention (physical activity toward health) for the self-management of CVD. Increasing physical activity in individuals with CVD was the primary behavior. The PATHway intervention was theoretically informed by the behavior change wheel and social cognitive theory. All relevant intervention functions, behavior change techniques, and policy categories were identified and translated into intervention content. Furthermore, a person-centered approach was adopted involving an iterative codesign process and extensive user testing. Education, enablement, modeling, persuasion, training, and social restructuring were selected as appropriate intervention functions. Twenty-two behavior change techniques, linked to the six intervention functions and three policy categories, were identified for inclusion and translated into PATHway intervention content. This paper details the use of the behavior change wheel and social cognitive theory to develop an eHealth intervention for the self-management of CVD. The systematic and transparent development of the PATHway intervention will facilitate the evaluation of intervention effectiveness and future replication.

Effectiveness of transcutaneous electrical nerve stimulation for treatment of hyperalgesia and pain.

Transcutaneous electrical nerve stimulation (TENS) is a nonpharmacologic treatment for pain relief. TENS has been used to treat a variety of painful conditions. This review updates the basic and clinical science regarding the use of TENS that has been published in the past 3 years (ie, 2005-2008). Basic science studies using animal models of inflammation show changes in the peripheral nervous system, as well as in the spinal cord and descending inhibitory pathways, in response to TENS. Translational studies show mechanisms to prevent analgesic tolerance to repeated application of TENS. This review also highlights data from recent randomized, placebo-controlled trials and current systematic reviews. Clinical trials suggest that adequate dosing, particularly intensity, is critical to obtaining pain relief with TENS. Thus, evidence continues to emerge from both basic science and clinical trials supporting the use of TENS for the treatment of a variety of painful conditions while identifying strategies to increase TENS effectiveness.

Embedding a user-centred approach in the development of complex behaviour change intervention to improve outcomes for young adults living with type 1 diabetes: The D1 Now Study.

Background: Type 1 diabetes (T1D) is an auto-immune condition which requires intensive self-management. Diabetes self-management is challenging, especially during young adulthood. Effective interventions to improve outcomes for young adults with T1D are needed. This paper describes the development of the D1 Now intervention, employing a user-centred approach to engage with stakeholders in parallel with the application of theory. Methods: Intervention development consisted of 4 phases: 1) the formation of a public and patient involvement (PPI) Young Adult Panel (YAP); 2) a systematic review to synthesise evidence regarding the effectiveness of interventions aimed at improving outcomes for young adults with T1D; 3) understand young adults' diabetes self-management behaviour through engagement with key stakeholders; and 4) an expert consensus meeting to discuss self-management strategies identified in Phase 1 and 3 that would form the core components of the D1 Now intervention. Results: The YAP resulted in meaningful involvement between young adults, researchers and service providers. The systematic review highlighted a lack of quality intervention studies. Qualitative findings highlighted how young adult self-management is driven by complex interactions between external resources, which influence capability, and motivation. The expert panel in Phase 4 highlighted focus areas to improve outcomes for young adults and implementation strategies. Subsequent to these 4 phases, 3 intervention components have been identified: 1) a key worker to liaise with the young adult; 2) an online portal to facilitate relationship building between staff and young adults; and 3) an agenda setting tool to facilitate joint decision-making. Conclusions: This study described the systematic development of an intervention underpinned by theoretical frameworks and PPI, and has identified components for the D1 Now intervention. The resulting intervention content will now be subject to an intervention optimisation process.

A Model to Predict Psychological- and Health-Related Adjustment in Men with Prostate Cancer: The Role of Post Traumatic Growth, Physical Post Traumatic Growth, Resilience and Mindfulness.

Background: Post traumatic growth (PTG) can be defined as positive change following a traumatic event. The current conceptualization of PTG encompasses five main dimensions, however, there is no dimension which accounts for the distinct effect of a physical trauma on PTG. The purpose of the present research was to test the role of PTG, physical post traumatic growth (PPTG), resilience and mindfulness in predicting psychological and health related adjustment. Method: Ethical approval was obtained from relevant institutional ethics committees. Participants (N = 241), who were at least 1 year post prostate cancer treatment, were invited to complete a battery of questionnaires either through an online survey or a paper and pencil package received in the post The sample ranged in age from 44 to 88 years (M = 64.02, SD = 7.76). Data were analysis using confirmatory factor analysis and structural equation modeling. Results: The physical post traumatic growth inventory (P-PTGI) was used to evaluate the role of PPTG in predicting adjustment using structural equation modeling. P-PTGI predicted lower distress and improvement of quality of life, whereas conversely, the traditional PTG measure was linked with poor adjustment. The relationship between resilience and adjustment was found to be mediated by P-PTGI. Conclusion: Findings suggest the central role of PTG in the prostate cancer survivorship experience is enhanced by the inclusion of PPTG. Adjusting to a physical trauma such as illness (internal transgressor) is unlike a trauma with an external transgressor as the physical trauma creates an entirely different framework for adjustment. The current study demonstrates the impact of PPTG on adjustment. This significantly adds to the theory of the development of PTG by highlighting the interplay of resilience with PTG, PPTG, and adjustment.

Measuring a new facet of post traumatic growth: Development of a scale of physical post traumatic growth in men with prostate cancer.

PURPOSE: This study developed a measure of physical post traumatic growth (physical post traumatic growth inventory; P-PTGI) in men with prostate cancer. METHODS: A pool of items was created from themes identified in a qualitative study. A quantitative study was then conducted to assess the psychometric properties of the P-PTGI in a sample of 693 prostate cancer survivors. RESULTS: Tests of dimensionality revealed that the 20-item P-PTGI contained two factors: Health Autonomy and Health Awareness. Results demonstrated that scale score reliability for the P-PTGI and its subscales was excellent. In support of the scale's convergent validity, scores on the P-PTGI correlated positively with mindfulness and quality of life, and correlated negatively with depression and anxiety. A statistically significant correlation between the P-PTGI and another robust indicator of post traumatic growth attests to its concurrent validity. CONCLUSIONS: While further investigation of the P-PTGI's psychometric properties is required, preliminary findings are promising.

Efficacy of transcutaneous electrical nerve stimulation (tens) for chronic low-back pain in a multiple sclerosis population: a randomized, placebo-controlled clinical trial.

OBJECTIVE: This study was designed to investigate the hypoalgesic effects of self-applied transcutaneous electrical nerve stimulation (TENS) on chronic low-back pain (LBP) in a multiple sclerosis (MS) population. METHODS: Ninety participants with probable or definite MS (aged 21 to 78 y) presenting with chronic LBP were recruited and randomized into 3 groups (n=30 per group): (1) low-frequency TENS group (4 Hz, 200 micros); (2) high-frequency TENS group (110 Hz, 200 micros); and (3) placebo TENS. Participants self-applied TENS for 45 minutes, a minimum of twice daily, for 6 weeks. Outcome measures were recorded at weeks 1, 6, 10, and 32. Primary outcome measures included: Visual Analog Scale for average LBP and the McGill Pain Questionnaire. Secondary outcome measures included: Visual Analog Scale for worst and weekly LBP, back and leg spasm; Roland Morris Disability Questionnaire; Barthel Index; Rivermead Mobility Index; Multiple Sclerosis Quality of Life-54 Instrument, and a daily logbook. Data were analyzed blind using parametric and nonparametric tests, as appropriate. RESULTS: Results indicated a statistically significant interactive effect between groups for average LBP (P=0.008); 1-way analysis of covariance did not show any significant effects at any time point once a Bonferonni correction was applied (P>0.05). However, clinically important differences were observed in some of the outcome measures in both active treatment groups during the treatment and follow-up periods. DISCUSSION: Although not statistically significant, the observed effects may have implications for the clinical prescription and the use of TENS within this population.

A double-blind investigation of the hypoalgesic effects of transcutaneous electrical nerve stimulation upon experimentally induced ischaemic pain.

The hypoalgesic effect of transcutaneous electrical nerve stimulation (TENS) at 2 different frequencies was assessed under double-blind conditions using a standardised form of the submaximum effort tourniquet technique. For the purpose of pain induction, 32 healthy naive female subjects attended on 2 occasions, the first during which baseline data were obtained and the second during which the women were randomly allocated to 1 of 4 groups: Control, Placebo, TENS-1 (110 Hz) or TENS-2 (4 Hz). In the treatment groups, 2 hydrogel electrodes were positioned over Erb's point and lateral to C6 and C7 vertebral spines. A TENS machine was applied for 10 min before the cuff was inflated and remained on for the duration of the pain procedure (12 min). Pain was measured using visual analogue scales (VAS) and the McGill Pain Questionnaire (MPQ) to assess 'current pain intensity' and 'worst pain experienced', respectively. Analysis of VAS scores showed significant differences between groups (ANOVA, P = 0.02), with the TENS-2 group showing a greater hypoalgesic effect than the other groups. One-factor ANOVA showed no significant differences in MPQ scores between groups. The results of this study have provided evidence of the hypoalgesic effects of TENS upon experimental ischaemic pain which were found to be frequency specific with the lower frequency used here (4 Hz) demonstrating the only significant effect.

The lack of hypoalgesic efficacy of H-wave therapy on experimental ischaemic pain.

The hypoalgesic effect of H-wave therapy (HWT) at various frequencies (2-60 Hz) was assessed using a standardised form of the submaximal effort tourniquet technique (SETT). Healthy human volunteers (n = 112; 56 men, 56 women) were required to attend on two occasions; on the first, baseline pain scores were obtained and on the second, 48 h later, subjects were randomly assigned to control, placebo or 1 of 5 H-wave treatment conditions. In the treatment groups 2 self-adhesive electrodes were attached to the ipsilateral Erb's point and just lateral to the spinous processes of C6/C7. H-wave stimulation commenced 10 min prior to pain induction and continued throughout the 12-min duration of the technique. In the placebo group electrodes were attached as normal but leads were connected to a dummy power output. Analysis of variance of the differences in visual analogue scale and McGill Pain Questionnaire scores showed no significant differences in the treatment groups compared to placebo or controls. These results do not provide convincing evidence for any hypoalgesic effects of HWT at the frequency parameters stated on the experimental model of pain used.

Acupuncture in the management of chronic low back pain: a blinded randomized controlled trial.

OBJECTIVE: To assess the efficacy of acupuncture in the treatment of chronic low back pain. METHODS: Patients (n = 60) with chronic low back pain were recruited and randomly allocated to either Acupuncture therapy or Placebo transcutaneous electrical nerve stimulation (TENS) groups. Patients were treated weekly for 6 weeks, and blinded assessments were carried out pre- and post-treatment using the McGill Pain Questionnaire (MPQ) and visual analog scales (VAS) for pain, the Short-form 36 quality-of-life questionnaire, and a simple range of motion measurement. A total of 46 patients completed the trial and were followed up at 6 months. RESULTS: Analysis of results using t tests showed that in both groups there were significant pre-post improvements for all scores, except for MPQ scores in the Placebo-TENS group. There was no significant difference between the 2 groups for any of the outcome measures at the end of treatment. Results from the 6-month follow-up would suggest that the response was better in the acupuncture group. DISCUSSION: Further research is necessary to fully assess the efficacy of this treatment in combating chronic low back pain using larger sample sizes or alternative control groups.

Effects of transcutaneous electrical nerve stimulation on pain, pain sensitivity, and function in people with knee osteoarthritis: a randomized controlled trial.

BACKGROUND: Transcutaneous electrical nerve stimulation (TENS) is commonly used for the management of pain; however, its effects on several pain and function measures are unclear. OBJECTIVE: The purpose of this study was to determine the effects of high-frequency TENS (HF-TENS) and low-frequency TENS (LF-TENS) on several outcome measures (pain at rest, movement-evoked pain, and pain sensitivity) in people with knee osteoarthritis. DESIGN: The study was a double-blind, randomized clinical trial. SETTING: The setting was a tertiary care center. PARTICIPANTS: Seventy-five participants with knee osteoarthritis (29 men and 46 women; 31-94 years of age) were assessed. INTERVENTION: Participants were randomly assigned to receive HF-TENS (100 Hz) (n=25), LF-TENS (4 Hz) (n=25), or placebo TENS (n=25) (pulse duration=100 microseconds; intensity=10% below motor threshold). MEASUREMENTS: The following measures were assessed before and after a single TENS treatment: cutaneous mechanical pain threshold, pressure pain threshold (PPT), heat pain threshold, heat temporal summation, Timed "Up & Go" Test (TUG), and pain intensity at rest and during the TUG. A linear mixed-model analysis of variance was used to compare differences before and after TENS and among groups (HF-TENS, LF-TENS, and placebo TENS). RESULTS: Compared with placebo TENS, HF-TENS and LF-TENS increased PPT at the knee; HF-TENS also increased PPT over the tibialis anterior muscle. There was no effect on the cutaneous mechanical pain threshold, heat pain threshold, or heat temporal summation. Pain at rest and during the TUG was significantly reduced by HF-TENS, LF-TENS, and placebo TENS. LIMITATIONS: This study tested only a single TENS treatment. CONCLUSIONS: Both HF-TENS and LF-TENS increased PPT in people with knee osteoarthritis; placebo TENS had no significant effect on PPT. Cutaneous pain measures were unaffected by TENS. Subjective pain ratings at rest and during movement were similarly reduced by active TENS and placebo TENS, suggesting a strong placebo component of the effect of TENS.

Exercise and Auricular Acupuncture for Chronic Low-back Pain: A Feasibility Randomized-controlled Trial.

OBJECTIVES: To evaluate the feasibility of a randomized-controlled trial (RCT) investigating the effects of adding auricular acupuncture (AA) to exercise for participants with chronic low-back pain (CLBP). METHODS: Participants with CLBP were recruited from primary care and a university population and were randomly allocated (n=51) to 1 of 2 groups: (1) "Exercise Alone (E)"-12-week program consisting of 6 weeks of supervised exercise followed by 6 weeks unsupervised exercise (n=27); or (2) "Exercise and AA (EAA)"-12-week exercise program and AA (n=24). Outcome measures were recorded at baseline, week 8, week 13, and 6 months. The primary outcome measure was the Oswestry Disability Questionnaire. RESULTS: Participants in the EAA group demonstrated a greater mean improvement of 10.7% points (95% confidence interval, -15.3,-5.7) (effect size=1.20) in the Oswestry Disability Questionnaire at 6 months compared with 6.7% points (95% confidence interval, -11.4,-1.9) in the E group (effect size=0.58). There was also a trend towards a greater mean improvement in quality of life, LBP intensity and bothersomeness, and fear-avoidance beliefs in the EAA group. The dropout rate for this trial was lower than anticipated (15% at 6 mo), adherence with exercise was similar (72% E; 65% EAA). Adverse effects for AA ranged from 1% to 14% of participants. DISCUSSION: Findings of this study showed that a main RCT is feasible and that 56 participants per group would need to be recruited, using multiple recruitment approaches. AA was safe and demonstrated additional benefits when combined with exercise for people with CLBP, which requires confirmation in a fully powered RCT.

An investigation of the development of analgesic tolerance to TENS in humans.

Transcutaneous electrical nerve stimulation (TENS) is a noninvasive modality used to control pain. Animal models show that repeated TENS application produces analgesic tolerance and cross-tolerance at spinal opioid receptors. The aim of the present investigation was to examine whether repeated application of TENS produces analgesic tolerance in humans. One hundred healthy subjects were randomly assigned to 1 of 4 groups: control, placebo, low-frequency (4Hz) or high-frequency (100Hz) TENS. TENS was applied daily for 5days to the nondominant upper limb; pressure-pain threshold (PPT) measurements were recorded before and after TENS. Temporal summation to mechanical stimulation was recorded on days 1 and 5, before and after TENS. Diffuse noxious inhibitory control (DNIC) was tested on day 5 using the cold pressor test and PPT measurements. There was an initial increase in PPTs in both low- and high-frequency TENS groups when compared with placebo or control groups. However, by day 5 this TENS-induced increase in PPT did not occur, and there was no difference between active TENS and placebo or control groups. High-frequency TENS decreased temporal summation on day 1 when compared with day 5. DNIC increased the PPT similarly in all groups. These data suggest that repeated daily application of TENS results in a decrease in its hypoalgesic effect by the fifth day and that the tolerance-like effect to repeated TENS results from tolerance at centrally located opioid receptors. The lack of change in DNIC response suggests that TENS and DNIC utilize separate pathways to produce analgesia. Repeated high-frequency and low-frequency transcutaneous electrical nerve stimulation produce analgesic tolerance in humans by the fourth and fifth day of treatment, respectively.

Adjusting pulse amplitude during transcutaneous electrical nerve stimulation (TENS) application produces greater hypoalgesia.

UNLABELLED: Transcutaneous electrical nerve stimulation (TENS) is a noninvasive technique used for pain modulation. During application of TENS there is a fading of current sensation. Textbooks of electrophysical agents recommend that pulse amplitude should be constantly adjusted. This seems to be accepted clinically despite the fact that there is no direct experimental evidence. The aim of the current study was to investigate the hypoalgesic effect of adjusting TENS pulse amplitude on pressure pain thresholds (PPTs) in healthy humans. Fifty-six healthy TENS naïve participants were recruited and randomly assigned to 1 of 4 groups (n = 14 per group): control, placebo TENS, fixed pulse amplitude TENS, and adjusted pulse amplitude TENS. Both active and placebo TENS were applied to the dominant forearm. PPTs were recorded from 2 points on the dominant forearm and hand before, during, and after 40 minutes of TENS. TENS increased the PPTs on the forearm (P = .003) and hand (P = .003) in the group that received the adjusted pulse amplitude when compared to all other groups. The mean final pulse amplitude for the adjusted pulse amplitude TENS group was 35.51 mA when compared to the fixed pulse amplitude TENS group, which averaged 31.37 mA (P = .0318). PERSPECTIVE: These results suggest that it is important to adjust the pulse amplitude during TENS application to get the maximal analgesic effect. We propose that the fading of current sensation allows the use of higher pulse amplitudes, which would activate a greater number of and deeper tissue afferents to produce greater analgesia.

Hypoalgesia in response to transcutaneous electrical nerve stimulation (TENS) depends on stimulation intensity.

UNLABELLED: Transcutaneous electrical nerve stimulation (TENS) is an electrophysical modality used for pain management. This study investigated the dose response of different TENS intensities on experimentally induced pressure pain. One hundred and thirty TENS naïve healthy individuals (18-64 years old; 65 males, 65 females) were randomly allocated to 5 groups (n = 26 per group): Strong Non Painful TENS; Sensory Threshold TENS; Below Sensory Threshold TENS; No Current Placebo TENS; and Transient Placebo TENS. Active TENS (80 Hz) was applied to the forearm for 30 minutes. Transient Placebo TENS was applied for 42 seconds after which the current amplitude automatically reset to 0 mA. Pressure pain thresholds (PPT) were recorded from 2 points on the hand and forearm before and after TENS to measure hypoalgesia. There were significant differences between groups at both the hand and forearm (ANOVA; P = .005 and .002). At 30 minutes, there was a significant hypoalgesic effect in the Strong Non Painful TENS group compared to: Below Sensory Threshold TENS, No Current Placebo TENS and Transient Placebo TENS groups (P < .0001) at the forearm; Transient Placebo TENS and No Current Placebo TENS groups at the hand (P = .001). There was no significant difference between Strong Non Painful TENS and Sensory Threshold TENS groups. The area under the curve for the changes in PPT significantly correlated with the current amplitude (r(2) = .33, P = .003). These data therefore show that there is a dose-response effect of TENS with the largest effect occurring with the highest current amplitudes. PERSPECTIVE: This study shows a dose response for the intensity of TENS for pain relief with the strongest intensities showing the greatest effect; thus, we suggest that TENS intensity should be titrated to achieve the strongest possible intensity to achieve maximum pain relief.

A new transient sham TENS device allows for investigator blinding while delivering a true placebo treatment.

UNLABELLED: This study compared a new transient sham transcutaneous electrical nerve stimulation (TENS) that delivers current for 45 seconds to an inactive sham and active TENS to determine the degree of blinding and influence on pain reduction. Pressure-pain thresholds (PPT), heat-pain thresholds (HPT), and pain intensities to tonic heat and pressure were measured in 69 healthy adults before and after randomization. Allocation investigators and subjects were asked to identify the treatment administered. The transient sham blinded investigators 100% of the time and 40% of subjects compared to the inactive sham that blinded investigators 0% of the time and 21% of subjects. Investigators and subjects were blinded only 7% and 13% of the time, respectively, with active TENS. Neither placebo treatment resulted in significant changes in PPT, HPT, or pain intensities. Subjects using higher active TENS amplitudes (> or =17 mAs) had significantly higher PPTs and lower pain intensities to tonic pressure than subjects using lower amplitudes (<17 mAs). HPTs and pain intensities to tonic heat were not significantly changed. The transient TENS completely blinds investigators to treatment and does not reduce pain, thereby providing a true placebo treatment. PERSPECTIVE: This article presents the benefits of a new transient sham TENS device for use in prospective, randomized, clinical trials. This device facilitates blinding of subjects and investigators to eliminate expectation bias and determine the true efficacy of TENS for use in clinical populations.