Reinforcing informed medication prescription for low back pain in the emergency department (RIME): a controlled interrupted time series implementation study protocol.

INTRODUCTION: Management guidelines for low back pain (LBP) recommend exclusion of serious pathology, followed by simple analgesics, superficial heat therapy, early mobilisation and patient education. An audit in a large metropolitan hospital emergency department (ED) revealed high rates of non-recommended medication prescription for LBP (65% of patients prescribed opioids, 17% prescribed benzodiazepines), high inpatient admission rates (20% of ED LBP patients), delayed patient mobilisation (on average 6 hours) and inadequate patient education (48% of patients). This study aims to improve medication prescription for LBP in this ED by implementing an intervention shown previously to improve guideline-based management of LBP in other Australian EDs. METHODS AND ANALYSIS: A controlled interrupted time series study will evaluate the intervention in the ED before (24 weeks; 20 March 2023-3 September 2023) and after (24 weeks; 27 November 2024-12 May 2024) implementation (12 weeks; 4 September 2023-26 November 2023), additionally comparing findings with another ED in the same health service. The multicomponent implementation strategy uses a formalised clinical flow chart to support clinical decision-making and aims to change clinician behaviour, through clinician education, provision of alternative treatments, educational resources, audit and feedback, supported by implementation champions. The primary outcome is the percentage of LBP patients prescribed non-recommended medications (opioids, benzodiazepines and/or gabapentinoids), assessed via routinely collected ED data. Anticipated sample size is 2000 patients (n=1000 intervention, n=1000 control) based on average monthly admissions of LBP presentations in the EDs. Secondary outcomes include inpatient admission rate, time to mobilisation, provision of patient education, imaging requests, representation to the ED within 6 months and healthcare costs. In nested qualitative research, we will study ED clinicians' perceptions of the implementation and identify how benefits can be sustained over time. ETHICS AND DISSEMINATION: This study received ethical approval from the Metro North Human Research Ethics Committee (HREC/2022/MNHA/87995). Study findings will be published in peer-reviewed journals and presented at international conferences and educational workshops. TRIAL REGISTRATION NUMBER: ACTRN12622001536752.

Characteristics and Effectiveness of Postoperative Rehabilitation Strategies in Ankle Fractures: A Systematic Review.

OBJECTIVES: To explore the characteristics and to report on the effectiveness of postoperative rehabilitation strategies for people with an ankle fracture. DATA SOURCES: PubMed, Cochrane Library, EMBASE, Web of Science, and CINAHL were searched to identify studies published from January 2010 to November 2021. STUDY SELECTION: Studies that described or evaluated postoperative rehabilitation strategies for surgically repaired ankle fractures were included. DATA EXTRACTION: Data on postoperative rehabilitation were extracted in accordance with the Template for Intervention Description and Replication guide. Quality was assessed using the National Heart, Lung, and Blood Institute's Study Quality Assessment Tools. DATA SYNTHESIS: Meta-analysis was planned to look at the effectiveness of postoperative rehabilitation strategies. Forty studies described postoperative rehabilitation strategies without evaluating effectiveness, whereas 15 studies focused on evaluating effectiveness. Because of the large variety in postoperative strategies and outcomes, narrative synthesis was deemed most suitable to answer our aims. Characteristics of postoperative rehabilitation strategies varied widely and were poorly described in a way that could not be replicated. Most of the studies (48%) used a late weight-bearing approach, although definitions and details around weight-bearing were unclear. CONCLUSIONS: Late weight-bearing has been the most common postoperative approach reported in the past 10 years. The variety of definitions around weight-bearing and the lack of details of rehabilitation regimens limit replication and affect current clinical practice. The authors propose to adopt consistent definitions and terminology around postoperative practices such as weight-bearing to improve evidence for effectiveness and ultimately patient outcomes. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Evaluating acupuncture and standard care for pregnant women with back pain: the EASE Back pilot randomised controlled trial (ISRCTN49955124).

BACKGROUND: Low back pain (LBP) and pelvic girdle pain (PGP) during pregnancy are common and often accepted as a 'normal' part of pregnancy. Many women receive little in the way of treatment, and yet pain interferes with sleep, daily activities and work and leads to increasing requests for induction of labour or elective caesarean section. The aim of this study was to assess the feasibility of a full RCT evaluating the benefit of acupuncture for pregnancy-related back pain. METHODS: This study is a single-centre, three-arm pilot RCT in one large maternity unit and associated antenatal and physiotherapy clinics. Women were eligible if they had pregnancy-related LBP with or without PGP. Exclusions included a history of miscarriage, high risk of early labour or pre-eclampsia, PGP only and previous acupuncture. Interventions were standard care (SC): a self-management booklet with physiotherapy if needed. SC+TA: the booklet and physiotherapy comprising true (penetrating) acupuncture, advice and exercise. SC+NPA: the booklet and physiotherapy comprising non-penetrating acupuncture, advice and exercise. Remote telephone randomisation used a 1:1:1 allocation ratio stratified by gestational weeks. Three measures of pain/function were compared to inform the primary outcome measure in a full RCT: the Pelvic Girdle Questionnaire (PGQ), Oswestry Disability Index (ODI) and 11-point 0-10 numerical rating scale for pain. Analysis focused on process evaluation of recruitment, retention, descriptive information on outcomes, adherence to treatment, occurrence of adverse events and impact of physiotherapist training. RESULTS: One hundred twenty-five women were randomised (45% of those eligible) between April and October 2013; 73% (n = 91) provided 8-week follow-up data. Three of six recruitment methods accounted for 82% of total uptake: screening questionnaire at the 20-week scan, community midwives issuing study cards, and self-referral following local awareness initiatives. Physiotherapists' self-confidence on managing pregnancy-related LBP improved post training. The PGQ is suitable as the primary outcome in a full trial. The average number of treatment sessions in both SC+TA and SC+NPA was six (in line with treatment protocols). No serious adverse events attributable to the trial treatments were reported. CONCLUSIONS: A full RCT is feasible and would provide evidence about the effectiveness of acupuncture and inform treatment choices for women with pregnancy-related LBP. TRIAL REGISTRATION: ISRCTN49955124.

Evaluating Acupuncture and Standard carE for pregnant women with Back pain (EASE Back): a feasibility study and pilot randomised trial.

BACKGROUND: Many pregnant women experience low back pain. Acupuncture appears to be a safe, promising intervention but evidence is needed about its clinical effectiveness and cost-effectiveness. OBJECTIVES: To assess the feasibility of a future large randomised controlled trial (RCT) testing the additional benefit of adding acupuncture to standard care (SC) for pregnancy-related back pain. DESIGN: Phase 1: a questionnaire survey described current care for pregnancy-related back pain. Focus groups and interviews with midwives, physiotherapists and pregnant women explored acceptability and feasibility of acupuncture and the proposed RCT. Phase 2: a single-centre pilot RCT. Participants were identified using six methods and randomised to SC, SC plus true acupuncture or SC plus non-penetrating acupuncture. PARTICIPANTS: Phase 1: 1093 physiotherapists were surveyed and 15 midwives, 21 physiotherapists and 17 pregnant women participated in five focus groups and 20 individual interviews. Phase 2: 125 women with pregnancy-related back pain participated. INTERVENTIONS: SC: a self-management booklet and onward referral for one-to-one physiotherapy (two to four sessions) for those who needed it. SC plus true acupuncture: the self-management booklet and six to eight treatments with a physiotherapist comprising true (penetrating) acupuncture, advice and exercise. SC plus non-penetrating acupuncture: the self-management booklet and six to eight treatments with a physiotherapist comprising non-penetrating acupuncture, advice and exercise. MAIN OUTCOME MEASURES: Pilot RCT outcomes included recruitment rates, treatment fidelity, follow-up rate, patient-reported pain and function, quality of life and health-care resource use. Birth and neonatal outcomes were also assessed. Staff overseeing outcome data collection were blind to treatment allocation. RESULTS: Phase 1: 629 (57.5%) physiotherapists responded to the survey, 499 were experienced in treating pregnancy-related back pain and reported 16 advice and 18 treatment options. Typical treatment comprised two to four individual sessions of advice and exercise over 6 weeks. Acupuncture was reported by 24%. Interviews highlighted the impact of back pain and paucity of effective interventions. Women and midwives strongly supported a RCT and expressed few concerns. Physiotherapists' concerns about acupuncture in pregnancy informed a training programme prior to the pilot RCT. Phase 2: We recruited 125 of 280 potentially eligible women (45%) in 6 months and randomised 41 to SC and 42 each to the SC plus true acupuncture and SC plus non-penetrating acupuncture arms. Analysis was conducted with 124 participants (41, 42 and 41, respectively) as one participant was randomised in error. Three of six recruitment methods were the most successful. In total, 10% of women (n = 4) randomised to SC alone accessed one-to-one physiotherapy and received an average of two treatments. The average number of treatments was six for both SC plus true acupuncture and SC plus non-penetrating acupuncture. Treatments were in line with protocols. Eight-week follow-up was 74%. Patient-reported outcomes (pain, function and quality of life) favoured the addition of acupuncture. There was no evidence of serious adverse events on mothers or birth and neonatal outcomes. The Pelvic Girdle Questionnaire was found to be an appropriate outcome measure for a future trial. CONCLUSIONS: A future main RCT is feasible and would be welcomed by women and clinicians. Longer-term follow-up and further follow-up efforts are recommended for a main trial. TRIAL REGISTRATION: Current Controlled Trials ISRCTN49955124. FUNDING: This project was funded by the National Institute of Health Research Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 20, No. 33. See the NIHR Journals Library website for further project information.

Physical Therapists' Views and Experiences of Pregnancy-Related Low Back Pain and the Role of Acupuncture: Qualitative Exploration.

BACKGROUND: Low back pain is often accepted as a "normal" part of pregnancy. Despite research suggesting that quality of life for women who are pregnant is adversely affected, most are advised to self-manage. Although the use of acupuncture for the management of persistent nonspecific low back pain has been recommended in recent UK national guidelines, its use in the management of pregnancy-related low back pain remains limited. OBJECTIVES: This study aimed to explore the perceptions and experiences of physical therapists involved in treating women who are pregnant and have low back pain with the objective of informing the pretrial training program for a pilot randomized trial (Evaluating Acupuncture and Standard care for pregnant womEn with Back pain [EASE Back]). DESIGN: A qualitative phenomenological method with purposive sampling was used in the study. METHODS: Three focus groups and 3 individual semistructured interviews were undertaken, and an iterative exploratory thematic analysis was performed. To ensure transparency of the research process and the decisions made, an audit trail was created. RESULTS: Twenty-one physical therapists participated, and emergent issues included: a lack of experience in treating pregnancy-related complaints, mixed messages from previous acupuncture education, a mistrust of the current evidence for acupuncture safety and effectiveness, and personal and professional fear of causing harm. CONCLUSIONS: The findings suggest that UK physical therapists are reluctant to use acupuncture in the management of pregnancy-related low back pain. The explanations for these findings include perceived lack of knowledge and confidence, as well as a pervasive professional culture of caution, particularly fears of inducing early labor and of litigation. These findings have been key to informing the content of the training program for physical therapists delivering acupuncture within the pilot EASE Back trial.

Alternating-frequency TENS effects on experimental pain in healthy human participants: a randomized placebo-controlled trial.

BACKGROUND: Transcutaneous electrical nerve stimulation (TENS) is a modality commonly used in pain management. OBJECTIVES: This study investigated the hypoalgesic effects of alternating-frequency TENS (4 Hz for 3 s/110 Hz for 3 s) on pressure pain threshold (PPT). METHODS: Two-hundred and eight healthy, pain-free volunteers (19 to 59 y old; 104 males, 104 females) were randomized to 8 groups: 6 active TENS groups, placebo, and control (n=26 per group). Parameter combinations were such that alternating-frequency TENS was combined with different levels of intensity "low" (strong but comfortable) or "high" (strong and uncomfortable but not painful). TENS was administered either at the forearm (segmental stimulation), at the ipsilateral leg (extrasegmental stimulation), or at both sites (dual-site stimulation) for 30 minutes and monitored for 30 further minutes. PPT measurements were taken bilaterally from the mid-point of first dorsal interosseous muscle, by an independent blinded rater, at baseline and at 6 subsequent 10-minute intervals. Square-root transformed data were analyzed using repeated measures analysis of covariance (baseline values and sex as covariates). RESULTS: Alternating-frequency TENS groups did not achieve significant hypoalgesic effects compared with placebo or control (P>0.05). The largest increase in PPT (from baseline) was 76.6 kPa with low-intensity segmental alternating frequency TENS at the 20-minute stimulation time point. This change from baseline is below a difference of 100 kPa that is considered to be a clinically meaningful change in hypoalgesia. DISCUSSION: The alternating-frequency setting does not result in large hypoalgesic effects such as those previously reported using fixed-frequency TENS.

Dose-specific effects of transcutaneous electrical nerve stimulation (TENS) on experimental pain: a systematic review.

OBJECTIVE: To determine the hypoalgesic effects of transcutaneous electrical nerve stimulation (TENS) parameter combinations on experimental models in healthy humans. METHODS: Searches were performed using the electronic databases Ovid MEDLINE, CINAHL, AMED, and Web of Science (from inception to December 2009). Manual searches of journals and reference lists of retrieved trials were also performed. Randomized controlled trials (RCTs) were included in the review if they compared the hypoalgesic effect of TENS relative with placebo and control, using an experimental pain model in healthy human participants. Two reviewers independently selected the trials, assessed their methodologic quality and extracted data. RESULTS: Forty-three RCTs were eligible for inclusion. A best evidence synthesis revealed: Overall "conflicting" (inconsistent findings in multiple RCTs) evidence of TENS efficacy on experimental pain irrespective of TENS parameters used. Overall intense TENS has "moderate" evidence of efficacy (1 high-quality and 2 low-quality trials). Conventional TENS has overall conflicting evidence of efficacy, this is derived from "strong" evidence of efficacy (generally consistent findings in multiple high-quality RCTs) on pressure pain but strong evidence of inefficacy on other pain models. "Limited" evidence (positive findings from 1 RCT) of hypoalgesia exists for some novel parameters. Low-intensity, low-frequency, local TENS has strong evidence of inefficacy. Inappropriate TENS (using "barely perceptible" intensities) has moderate evidence of inefficacy. DISCUSSION: The level of hypoalgesic efficacy of TENS is clearly dependent on TENS parameter combination selection (defined in terms of intensity, frequency, and stimulation site) and experimental pain model. Future clinical RCTs may consider these TENS dose responses.

Defining an adequate dose of acupuncture using a neurophysiological approach--a narrative review of the literature.

Many different styles of acupuncture practice exist, and lack of agreement on the optimal acupuncture treatment for any particular condition may mean that some patients do not receive the best treatment. This uncertainty also makes the negative results of sham controlled trials difficult to interpret. Unless we can be sure that both adequate acupuncture and an inactive sham were used in a particular trial, then that trial should not be interpreted as dismissing acupuncture for that condition. Acupuncture practice clearly involves much more than needling procedures, but there is a strong argument for elucidating the role of those needling procedures first. The components of acupuncture needling procedures have been described in the STRICTA document, but it is also clear that the patient's perception of needling is relevant for the outcome of treatment. We therefore recommend the concept of 'dose' of acupuncture needling, which should include both the stimulus given to the patient, and certain aspects of the patient's perceptions and response that are known to be linked to the subsequent therapeutic response. We propose the following definition of dose: the physical procedures applied in each session, using one or more needles, taking account of the patient's resulting perception (sensory, affective and cognitive) and other responses (including motor). The dose may be affected by the state of the patient (eg nervous, immune and endocrine systems); different doses may be required for different conditions. The constituents of an adequate dose can be established initially by clinical opinion and subsequently by empirical evidence from experimental studies, which may be either clinical or basic research studies. Systematic reviews which do not consider the adequacy of the acupuncture treatment may have unreliable conclusions. Out of 47 recent systematic reviews, only six have applied some criteria for adequacy. Five used a rating system or conducted a subgroup analysis, and one excluded studies from the analysis altogether if they did not meet criteria for adequacy. Research into what constitutes an adequate dose of acupuncture has long been neglected and is now urgent. Clinical studies that compare the effects of different treatment protocols are probably the most reliable source of evidence, and may also demonstrate a dose-response relationship.

Effects of simultaneous dual-site TENS stimulation on experimental pain.

Transcutaneous electrical nerve stimulation (TENS) is commonly used for pain relief. However, little robust research exists regarding the combination of parameters required to provide effective doses. This study investigated the hypoalgesic effects of different parameter combinations, applied simultaneously at two sites (segmental and extrasegmental), on pressure pain threshold (PPT) in pain-free humans. Two-hundred and eight volunteers (median age 22 years, range 20-26) were randomized to eight groups: six active TENS groups, placebo and control. Parameter combinations were such that frequency always differed at each site (110 Hz or 4 Hz), but intensity could be either the same or different levels: high (to tolerance without pain) or low (strong but comfortable). TENS was administered to the forearm over the radial nerve and the ipsilateral leg below the fibular head for 30 min with monitoring for 30 further minutes. PPT measurements were taken bilaterally from the mid-point of first dorsal interosseous muscle, by an independent blinded rater, at baseline and at six subsequent 10-min intervals. Log-transformed data were analysed using repeated-measures analysis of covariance (baseline values and gender as covariates). Those groups using high-intensity stimulation at the segmental stimulation sites showed significantly greater hypoalgesia than placebo (p < 0.025 in each case). The largest hypoalgesic effect was for simultaneous high-intensity stimulation at segmental and extrasegmental sites, using different frequencies. These results reaffirm that high-intensity stimulation (regardless of frequency) is of fundamental importance in effective dosage.

Acupuncture as an adjunct to exercise based physiotherapy for osteoarthritis of the knee: randomised controlled trial.

OBJECTIVE: To investigate the benefit of adding acupuncture to a course of advice and exercise delivered by physiotherapists for pain reduction in patients with osteoarthritis of the knee. DESIGN: Multicentre, randomised controlled trial. SETTING: 37 physiotherapy centres accepting primary care patients referred from general practitioners in the Midlands, United Kingdom. PARTICIPANTS: 352 adults aged 50 or more with a clinical diagnosis of knee osteoarthritis. INTERVENTIONS: Advice and exercise (n=116), advice and exercise plus true acupuncture (n=117), and advice and exercise plus non-penetrating acupuncture (n=119). MAIN OUTCOME MEASURES: The primary outcome was change in scores on the Western Ontario and McMaster Universities osteoarthritis index pain subscale at six months. Secondary outcomes included function, pain intensity, and unpleasantness of pain at two weeks, six weeks, six months, and 12 months. RESULTS: Follow-up rate at six months was 94%. The mean (SD) baseline pain score was 9.2 (3.8). At six months mean reductions in pain were 2.28 (3.8) for advice and exercise, 2.32 (3.6) for advice and exercise plus true acupuncture, and 2.53 (4.2) for advice and exercise plus non-penetrating acupuncture. Mean differences in change scores between advice and exercise alone and each acupuncture group were 0.08 (95% confidence interval -1.0 to 0.9) for advice and exercise plus true acupuncture and 0.25 (-0.8 to 1.3) for advice and exercise plus non-penetrating acupuncture. Similar non-significant differences were seen at other follow-up points. Compared with advice and exercise alone there were small, statistically significant improvements in pain intensity and unpleasantness at two and six weeks for true acupuncture and at all follow-up points for non-penetrating acupuncture. CONCLUSION: The addition of acupuncture to a course of advice and exercise for osteoarthritis of the knee delivered by physiotherapists provided no additional improvement in pain scores. Small benefits in pain intensity and unpleasantness were observed in both acupuncture groups, making it unlikely that this was due to acupuncture needling effects. TRIAL REGISTRATION: Current Controlled Trials ISRCTN88597683 [controlled-trials.com] .

Effects of intensity of electroacupuncture upon experimental pain in healthy human volunteers: a randomized, double-blind, placebo-controlled study.

Electroacupuncture is commonly used for pain relief. Despite an extensive evidence-base guiding the selection of stimulation parameters, little methodologically robust research exists regarding the level of intensity required to provide effective doses. This study investigated the hypoalgesic effects of two stimulation intensities compared to placebo on pressure pain thresholds (PPTs) in pain-free humans. Forty-eight acupuncture-naïve volunteers (mean age 23), stratified by gender, were screened for relevant contraindications and randomly allocated to four groups: control, placebo, high-intensity ("to tolerance but sub-noxious") or low-intensity ("strong but comfortable"). True or placebo electroacupuncture, using the Streitberger placebo needle, was administered to acupoints on dominant forearm (LI10, TH5) and ipsilateral leg (GB34, ST38). True needles (30 mm long, 0.3 mm diameter) were inserted 20-25 mm and "de-qi" was elicited from active groups, prior to administering 30 min of 4 Hz, 200 micros electroacupuncture. No electrical stimulation was performed on control and placebo groups, and placebo needles were used. After the intervention period, all needles were removed. Volunteers were monitored for 30 further minutes. Two PPT measurements were taken bilaterally from muscle bellies of first dorsal interosseous by an independent rater, at baseline and at six subsequent 10-min intervals. Square-root transformed data were analysed using repeated-measures ANOVA, with baseline data as covariate. The high-intensity group was significantly different from the placebo group for both measurement sites (p=.020, p=.033). The control group displayed stable PPT readings over time. No significant differences were observed between the placebo and control groups. These findings suggest that high-intensity levels may be important in optimal dose selection.

Is acupuncture a useful adjunct to physiotherapy for older adults with knee pain?: the "acupuncture, physiotherapy and exercise" (APEX) study [ISRCTN88597683].

BACKGROUND: Acupuncture is a popular non-pharmacological modality for treating musculoskeletal pain. Physiotherapists are one of the largest groups of acupuncture providers within the NHS, and they commonly use it alongside advice and exercise. Conclusive evidence of acupuncture's clinical effectiveness and its superiority over sham interventions is lacking. The Arthritis Research Campaign (arc) has funded this randomised sham-controlled trial which addresses three important questions. Firstly, we will determine the additional benefit of true acupuncture when used by physiotherapists alongside advice and exercise for older people presenting to primary care with knee pain. Secondly, we will evaluate sham acupuncture in the same way. Thirdly, we will investigate the treatment preferences and expectations of both the participants and physiotherapists participating in the study, and explore the effect of these on clinical outcome. We will thus investigate whether acupuncture is a useful adjunct to advice and exercise for treating knee pain and gain insight into whether this effect is due to specific needling properties. METHODS/DESIGN: This randomised clinical trial will recruit 350 participants with knee pain to three intervention arms. It is based in 43 community physiotherapy departments in 21 NHS Trusts in the West Midlands and Cheshire regions in England. Patients aged 50 years and over with knee pain will be recruited. Outcome data will be collected by self-complete questionnaires before randomisation, and 6 weeks, 6 months and 12 months after randomisation and by telephone interview 2 weeks after treatment commences. The questionnaires collect demographic details as well as information on knee-related pain, movement and function, pain intensity and affect, main functional problem, illness perceptions, self-efficacy, treatment preference and expectations, general health and quality of life. Participants are randomised to receive a package of advice and exercise; or this package plus real acupuncture; or this package plus sham acupuncture. Treatment details are being collected on a standard proforma. Interventions are delivered by experienced physiotherapists who have all received training in acupuncture to recognised national standards. The primary analysis will investigate the main treatment effects of real or sham acupuncture as an adjunct to advice and exercise. DISCUSSION: This paper presents detail on the rationale, design, methods, and operational aspects of the trial.

Effects of TENS frequency, intensity and stimulation site parameter manipulation on pressure pain thresholds in healthy human subjects.

UNLABELLED: This study evaluated the effects of varying frequency, intensity and stimulation site, of transcutaneous electrical nerve stimulation (TENS) in an experimental model of pain. In a double-blind design 240 volunteers were randomised to one of six experimental TENS groups, a sham TENS or control (n=30 per group; gender balanced). Two TENS frequencies (110 or 4 Hz) and two intensities (strong but comfortable or highest tolerable) at a fixed pulse duration (200 micros) were applied at three sites relative to the measurement site (segmentally, extrasegmentally or a combination of these), for 30 min. Pressure pain thresholds (PPT) were measured using a pressure algometer, in the first dorsal interosseous muscle, every 10 min, during stimulation and for a further 30 min. The high frequency, high intensity segmental, and combined stimulation groups, showed rapid onset and significant hypoalgesic effects. This effect was sustained for 20 min post-stimulation in the high frequency segmental group. All other TENS intervention groups showed hypoalgesic responses similar to the sham TENS group, and none of these groups reached a clinically significant hypoalgesic level. CONCLUSIONS: The role of TENS frequency, intensity and site are pivotal to achieving optimal hypoalgesic effects, during and after stimulation. Clinical applications of these parameter combinations require further investigations.

Gender differences in pressure pain threshold in healthy humans.

UNLABELLED: AIMS OF INVESTIGATION: To quantify the magnitude of putative gender differences in experimental pressure pain threshold (PPT), and to establish the relevance of repeated measurements to any such differences. METHODS: Two separate studies were undertaken. A pressure algometer was used in both studies to assess PPT in the first dorsal interosseous muscle. Force was increased at a rate of 5 N /s. In study 1, two measurements were taken from 240 healthy volunteers (120 males, 120 females; mean age 25 years) giving a power for statistical analysis of beta=0.80 at alpha=0.01. In study two, 30 subjects (15 males, 15 females mean age 28 years) were randomly selected from study one. Fourteen repeated PPT measurements were recorded at seven, 10 min intervals. Mean PPT data for gender groups, from both studies, were analysed using analysis of covariance with repeated measures, and age as the covariate. RESULTS: The mean PPT for each of the two measurements in study one showed a difference between gender of 12.2 N (f=30.5 N, m=42.7 N) and 12.8 N (f=29.5 N, m=42.3 N), respectively, representing a difference of 28% with females exhibiting a lower threshold. In study two, the mean difference calculated from 14 PPT repeated measurements over a 1h period was comparable to that in study one at 12.3N (range 10.4-14.4 N) again females exhibited the lower threshold. The differences in mean PPT values between gender were found to be significant in both study one, at (P<0.0005, F=37.8, df=1) and study two (P=0.01, F=7.6, df=1). No significant differences were found in either study with repeated measurement (P=0.892 and P=0.280), or on the interaction of gender and repeated measurement after controlling for age (P=0.36 and P=0.62). CONCLUSION: Healthy females exhibited significantly lower mean PPTs in the first dorsal interosseous muscle than males, which was maintained for fourteen repeated measures within a 1 h period. This difference is likely to be above clinically relevant levels of change, and it has clear implications for the use of different gender subjects in laboratory based experimental designs utilising PPT as an outcome measure.

Sensory stimulation (TENS): effects of parameter manipulation on mechanical pain thresholds in healthy human subjects.

Transcutaneous electrical nerve stimulation (TENS) is a popular form of electrostimulation. Despite an extensive research base, there remains no consensus regarding the parameter selection required to achieve maximal hypoalgesic effects. The aim of this double blind, sham-controlled study was to investigate the relative hypoalgesic effects of different TENS parameters (frequency, intensity and stimulation site) upon experimentally induced mechanical pain. Two hundred and forty participants were recruited in order to provide statistical analysis with 80% power at alpha = 0.05. Subjects were randomised to one of the six TENS groups, a control, and a sham TENS group (n = 30, 15 males, 15 females, per group). TENS groups differed in their combinations of stimulation; frequency (4 or 110 Hz), intensity ('to tolerance' or 'strong but comfortable') and stimulation site (segmental--over the distribution of the radial nerve or, extrasegmental--over acupuncture point 'gall bladder 34', or a combination of both segmental and extrasegmental). Pulse duration was fixed at 200 micros. Stimulation was delivered for 30 min and subjects were then monitored for a further 30 min. Mechanical pain threshold (MPT) was measured using a pressure algometer and taken from the first dorsal interosseous muscle of the dominant hand, ipsilateral to the stimulation site. MPT measures were taken, at baseline, and at 10-min intervals for 60 min. Difference scores were analysed using repeated measures and one-way ANOVA and relevant post hoc tests. Low frequency, high intensity, extrasegmental stimulation produced a rapid onset hypoalgesic effect, which increased during the stimulation period (P < 0.0005 control and sham) and was sustained for 30 min post-stimulation (P < 0.0005(control), P = 0.024(sham)). Whilst high frequency, 'strong but comfortable' intensity, segmental stimulation produced comparable hypoalgesic levels during stimulation, this effect was not sustained post-stimulation. Stimulation at a combination of the two sites did not produce any greater hypoalgesic effects. These results may have implications for the clinical use of sensory stimulation.