Study of the effects of various transcutaneous electrical nerve stimulation (TENS) parameters upon the RIII nociceptive and H‐reflexes in humans

Despite over two decades of clinical use, the neurophysiological and anti‐nociceptive effects of transcutaneous electrical nerve stimulation (TENS) have yet to be definitively described. The current study was designed to examine the effect of TENS on the RIII nociceptive reflex elicited in healthy human subjects; the H‐reflex was measured concomitantly to monitor changes in α‐motoneuron excitability. Following approval from the university’s ethical committee, 50 healthy human volunteers (25 male and 25 female) participated in the study. The subjects ranged in age from 18 to 30 years (mean 22, SD 3). Subjects were randomly allocated equally to a control group or one of four TENS groups. In the TENS groups, stimulation was applied for a total of 15 min over the sural nerve in the left leg. Ipsilateral RIII and H‐reflexes were recorded five times during the 45 min experimental period. In addition, subjects also rated pain associated with the RIII reflex using a computerized visual analogue scale (VAS). Statistical analysis using two‐way repeated‐measures ANOVA showed no differences between groups for H‐reflex, RIII reflex nor VAS data. These results suggest that TENS does not significantly affect either of the two reflexes, at least using the parameters and application time in the current study.     

Comparison of the analgesic efficacy of interferential therapy and transcutaneous electrical nerve stimulation

Objective

To compare the analgesic efficacy of interferential therapy (IFT) and transcutaneous electrical nerve stimulation (TENS) using an experimental cold pain model.

Design

Randomised controlled trial with repeated measures design.

Setting

University research laboratory.

Participants

Twenty healthy subjects.

Interventions

IFT and TENS applied to each subject on different days.

Main outcome measures

Cold pain threshold (time), intensity and unpleasantness (visual analogue scales).

Results

The mean cold pain threshold with a TENS intervention was higher than that with IFT. A training effect was evident as subjects’ responses become more consistent with repeated exposure to stimulation and the testing procedure. Using data from the second testing sessions, the differences in pain threshold between IFT and TENS for the two during-intervention (T3 and T4) measures were statistically significant (T3 difference in the means 5.9 seconds, 99% confidence interval 3.1 to 8.7 seconds; T4 difference in the means 6.6 seconds, 99% confidence interval 3.8 to 9.4 seconds). No significant differences were identified in pain intensity and unpleasantness ratings.

Conclusions

TENS is more effective than IFT at increasing cold pain thresholds in healthy subjects, and this effect increases with repeated exposures. Future trials should include a familiarisation session prior to testing to increase the consistency of subjects’ responses. The clinical implications of these effects need investigation.     

Alteration of interferential current and transcutaneous electrical nerve stimulation frequency: effects on nerve excitation.

OBJECTIVES: To investigate the effects of different interferential current (IC) and transcutaneous electrical nerve stimulation (TENS) frequencies on sensory, motor, and pain thresholds. STUDY DESIGN: Single blind, repeated measures design. SETTING: Laboratory. PARTICIPANTS: Women students 18 to 30 years old (n = 24). INTERVENTIONS: Premodulated IC and square-wave TENS pulses (125micros phase duration) were applied over the median nerve at a range of frequencies in all subjects. MAIN OUTCOME MEASURES: The peak current (in milliamperes) was recorded twice at each threshold for each frequency, and averaged. RESULTS: Both IC and TENS displayed a statistically significant effect of frequency for each threshold. However, frequency effects with IC were not well defined and were of small magnitude. Pure 4kHz current (0Hz amplitude modulated frequency) with IC did not produce effects different from those produced when an amplitude modulated frequency was included. With TENS, frequency effects were very clearly observed, with a distinct increase in the current intensity at each threshold as frequency decreased. CONCLUSIONS: It is postulated that the medium frequency component of IC is the main parameter in stimulation, contrary to traditional claims of the amplitude modulated frequency being important. TENS was shown to be a more adaptable method of stimulating these nerve pathways than IC.     

Comparative analgesic effects of H-wave therapy and transcutaneous electrical nerve stimulation on pain threshold in humans.

OBJECTIVE: To assess the comparative analgesic efficacy of H-wave therapy (HWT) and transcutaneous electrical nerve stimulation (TENS) using a mechanical model of pain threshold measurement. STUDY DESIGN: Forty-eight healthy human volunteers (24 women, 24 men) were recruited and randomly assigned into one of six experimental groups; control, HWT (placebo, 2Hz, or 60Hz), or TENS (placebo or 110Hz). For each subject, mechanical pain threshold (MPT) measurements were recorded at three standardized recording points marked on the dorsal web space of the dominant hand. Two MPT measurements were recorded at each point at the following time intervals: before treatment was initiated (baseline), after each of three consecutive 10-minute periods of stimulation (HWT or TENS), and at four intervals within 30 minutes after stimulation. In the control and placebo groups MPT measurements were recorded at similar time intervals. RESULTS: Difference scores, calculated from patients' baseline values, were analyzed by ANOVA for each of the three recording points. Although results showed a significant increase in MPT levels in all three stimulation groups when compared with their relative placebo (indicating a hypoalgesic effect), no differences were observed between the different modalities or HWT frequencies. Significant hypoalgesia continued for 5 minutes after stimulation. CONCLUSION: The findings showed that HWT and TENS provided localized hypoalgesia during stimulation and for up to 5 minutes after it. No frequency- or modality-specific effects were observed between the groups.     

The effects of transcutaneous electrical nerve stimulation on spasticity

Abstract

Transcutaneous electrical nerve stimulation (TENS) is commonly used in the treatment of chronic and acute pain with possible mechanisms of action including segmental inhibition, release of endogenous opioids, counter-irritation, nerve conduction block, and placebo. Although not frequently used in current practice, there is some evidence that TENS has an effect on spasticity in neurological conditions such as stroke, spinal cord injury, and multiple sclerosis. This paper reviews the results of studies undertaken to date, evaluating not only the effects of TENS on spasticity, but also the impact of different TENS parameters on its overall effectiveness. Recommendations based on the current evidence for the use of TENS in the treatment of spasticity are made, as well as suggestions for further study.     

The effects of transcutaneous electrical nerve stimulation on post-cesarean pain

The purpose of this study was to examine the effect of continuous transcutaneous electrical nerve stimulation (TENS) near the incision site on post-cesarean pain and on analgesic intake during the early postoperative period. This investigation utilised a 2-group (TENS-treated and placebo TENS-treated), single-blind experimental design. Eighteen multiparous women, each having undergone an elective cesarean delivery, participated in the study. Nine patients received TENS and nine placebo stimulation. The treatment was continuous through to the third day following the day of surgery. The McGill Pain Questionnaire was used to estimate the three most frequent types of post-cesarean-associated pain, and records of the patients' analgesic intake were obtained from hospital charts. The results suggest that TENS was significantly more effective than placebo TENS in reducing cutaneous, movement-associated incisional pain. However, pain resulting from internal structures, i.e., deep pain, afterbirth pain (due to uterine contractions), and the somatic pain associated with decreased peristalsis (gas pains) were not amenable to TENS. No significant differences in analgesic intake were observed. The possible reasons for these findings are discussed.     

An investigation into the analgesic effects of interferential currents and transcutaneous electrical nerve stimulation on experimentally induced ischemic pain in otherwise pain-free volunteers

BACKGROUND AND PURPOSE: Interferential currents (IFC) and transcutaneous electrical nerve stimulation (TENS) are used for pain management. This study compared the analgesic effects of IFC and TENS on experimentally induced ischemic pain in otherwise pain-free subjects using a modified version of the submaximal-effort tourniquet technique. SUBJECTS: The subjects were 30 volunteers (18 male, 12 female) without known pathology that could cause pain. Their mean age was 33.5 years (SD=9.9, range=21-54). METHOD: A single-blind, sham-controlled, parallel-group method was used. The primary outcome measure was the change in the self-report of pain intensity during 1 of 3 possible interventions: (1) IFC, (2) TENS, or (3) sham electrotherapy. The IFC and TENS were administered on the forearm, and the sham electrotherapy group received no current output via a dummy stimulator. RESULTS: A 2-way repeated-measures analysis of variance revealed that there was no change in pain intensity during treatment when all 3 groups were considered together. Further analysis revealed that IFC reduced pain intensity when compared with sham electrotherapy but not when compared only with TENS. DISCUSSION AND CONCLUSION: There were no differences in the magnitude of analgesia between IFC and TENS. Interferential currents reduced pain intensity to a greater extent than sham electrotherapy.     

A review of the treatment of chronic low back pain with acupuncture-like transcutaneous electrical nerve stimulation and transcutaneous electrical nerve stimulation

A meta-analysis of published studies was carried out to evaluate the effectiveness of acupuncture-like transcutaneous electrical nerve stimulation (ALTENS) and transcutaneous electrical nerve stimulation (TENS) in controlling pain and improving function in patients with chronic low back pain. Studies in English were identified by searches of EMBASE, MEDLINE, CISCOM and AMED. Other studies were located by citation tracking, searching by hand bibliographies and conference reports, and direct contact with subject experts. Studies were included in the meta-analysis if they were randomized controlled trials comparing ALTENS or TENS with a credible placebo in patients with low back pain of more than 8 weeks duration. Two reviewers extracted data on reduction in pain, changes in range of movement and functional status as well as determining the power of the included studies. Sixty-eight studies were initially identified, of which six (two using ALTENS and four using TENS) involving a total of 288 patients with mixed low back pathologies met the inclusion criteria for meta-analysis. The odds ratio (OR) of improvement in pain was calculated: ALTENS/TENS vs placebo OR = 2.1 (95% Cl 1.3–3.4) ALTENS vs placebo OR = 7.2 (95% CI 2.6–20.1), TENS vs placebo OR = 1.5 (95% CI 0.9–2.6). OR for range of motion (ROM) on ALTENS vs placebo was 6.6 (95% CI 2.4–18.6). There were insufficient data to assess the effect of TENS alone on ROM, functional status and return to work. Similarly there were not enough data to assess ALTENS and functional status and return to work. There is limited statistical evidence that ALTENS and TENS reduce pain and improve function in patients with chronic low back pain, at least in the short term. This review and analysis is severely restricted by the lack of quality, randomized controlled trials. Even 25 years since the introduction of these treatments, powerful randomized controlled studies on the most appropriate use of TENS/ALTENS for the management of chronic low back pain have yet to be produced.     

经皮神经电刺激对周围神经侧侧缝合后神经再生作用的实验研究

目的：研究经皮神经电刺激对周围神经侧侧缝合后神经再生的影响.方法：健康大耳白兔18只,显露坐骨神经及其分叉处,胫神经和腓总神经相邻神经束膜及外膜缝合.将动物肢体分为实验侧与对照侧.实验侧术后第2天,经皮神经电刺激右下肢,刺激参数：方波,波长0.3ms,频率5Hz,电流峰值3-10mA.刺激时间：每日1次,每次30min,持续6周.左后肢不给予电刺激.实验动物分组：A组（术后电刺激3周）,B组（术后电刺激6周）,C组（术后电刺激16周）;每组6只.结果：通过观察电镜、肌电图,实验侧明显优于对照侧.神经侧侧吻合各组在各时间点依次切开原手术切口,检测C组动物腓总神经的运动传导速度,CAMP的振幅及潜伏期,实验侧神经传导速度及CAMP振幅均优于对照侧,两者差异有显著性意义（P＜0.05）.实验侧CAMP的潜伏期慢于对照侧,两者差异无显著性意义（P＞0.05）.切断各组标本,距吻合口处下方5mm,腓总神经中再生有髓纤维数目实验侧再生有髓纤维均多于对照侧,两者差异有显著性意义（P＜0.05）.结论：神经侧侧吻合后有神经侧支发芽生长,可作为修复神经损伤的一种方法;经皮神经电刺激在提高神经侧侧吻合后神经侧支发芽能力有积极作用.     

Comparison of the efficacy of transcutaneous electrical nerve stimulation, interferential currents, and shortwave diathermy in knee osteoarthritis: a double-blind, randomized, controlled, multicenter study

Atamaz FC, Durmaz B, Baydar M, Demircioglu OY, Iyiyapici A, Kuran B, Oncel S, Sendur OF. Comparison of the efficacy of transcutaneous electrical nerve stimulation, interferential currents, and shortwave diathermy in knee osteoarthritis: a double-blind, randomized, controlled, multicenter study.ObjectiveTo compare the effectiveness of transcutaneous electrical nerve stimulation (TENS), interferential currents (IFCs), and shortwave diathermy (SWD) against each other and sham intervention with exercise training and education as a multimodal package.DesignA double-blind, randomized, controlled, multicenter trial.SettingDepartments of physical medicine and rehabilitation in 4 centers.ParticipantsPatients (N=203) with knee osteoarthritis (OA).InterventionsThe patients were randomized by the principal center into the following 6 treatment groups: TENS sham, TENS, IFCs sham, IFCs, SWD sham, and SWD. All interventions were applied 5 times a week for 3 weeks. In addition, exercises and an education program were given. The exercises were carried out as part of a home-based training program after 3 weeks' supervised group exercise.Main Outcome MeasuresPrimary outcome was a visual analog scale (0–100mm) to assess knee pain. Other outcome measures were time to walk a distance of 15m, range of motion, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Nottingham Health Profile, and paracetamol intake (in grams).ResultsWe found a significant decrease in all assessment parameters (P<.05), without a significant difference among the groups except WOMAC stiffness score and range of motion. However, the intake of paracetamol was significantly lower in each treatment group when compared with the sham groups at 3 months (P<.05). Also, the patients in the IFCs group used a lower amount of paracetamol at 6 months (P<.05) in comparison with the IFCs sham group.ConclusionsAlthough all groups showed significant improvements, we can suggest that the use of physical therapy agents in knee OA provided additional benefits in improving pain because paracetamol intake was significantly higher in the patients who were treated with 3 sham interventions in addition to exercise and education.     

The effects of unilateral transcutaneous electrical nerve stimulation of the median nerve on bilateral somatosensory thresholds

Transcutaneous electrical nerve stimulation (TENS) is used to relieve acute and chronic pain. TENS electrodes are applied at the site of pain or in segments related to the pain, although there is limited research to support either approach. This study investigated the effects of unilateral TENS on mechanical and thermal thresholds at ipsilateral and contralateral sites in healthy human participants. Sensory perception thresholds were measured on the ipsilateral and contralateral thenar eminence of 16 volunteers for von Frey filaments, sharpness, warm, cold and heat pain. TENS was administered over the right median nerve for 10 min at 100 pulses per second (pps) and an intensity which elicited mild tingling in the hand. During TENS, ipsilateral threshold was greater than contralateral threshold for all sensory modalities, although differences were less marked for thermal stimuli. TENS effects had disappeared 30 min after TENS had been switched off although there was a tendency for thermal thresholds to remain elevated. We conclude that during stimulation, TENS elevates somatosensory thresholds within the distribution of the stimulated nerve. The rapid and short-lived ipsilateral effect is consistent with findings from animal studies and suggests a central segmental mechanism.     

Conditioning transcutaneous electrical nerve stimulation induces delayed gating effects on cortical response: a magnetoencephalographic study

The present study was undertaken to investigate after-effects of 7 Hz non-painful prolonged stimulation of the median nerve on somatosensory-evoked fields (SEFs). The working hypothesis that conditioning peripheral stimulations might produce delayed interfering ("gating") effects on the response of somatosensory cortex to test stimuli was evaluated. In the control condition, electrical thumb stimulation induced SEFs in ten subjects. In the experimental protocol, a conditioning median nerve stimulation at wrist preceded 6 electrical thumb stimulations. Equivalent current dipoles fitting SEFs modeled responses of contralateral primary area (SI) and bilateral secondary somatosensory areas (SII) following control and experimental conditions. Compared to the control condition, conditioning stimulation induced no amplitude modulation of SI response at the initial stimulus-related peak (20 ms). In contrast, later response from SI (35 ms) and response from SII were significantly weakened in amplitude. Gradual but fast recovery towards control amplitude levels was observed for the response from SI-P35, while a slightly slower cycle was featured from SII. These findings point to a delayed "gating" effect on the synchronization of somatosensory cortex after peripheral conditioning stimulations. This effect was found to be more lasting in SII area, as a possible reflection of its integrative role in sensory processing.     

One-shot percutaneous electrical nerve stimulation vs. transcutaneous electrical nerve stimulation for low back pain: comparison of therapeutic effects

OBJECTIVE: To investigate the therapeutic effects of one shot of low-frequency percutaneous electrical nerve stimulation one shot of transcutaneous electrical nerve stimulation in patients with low back pain. DESIGN: In total, 133 low back pain patients were recruited for this randomized, control study. Group 1 patients received medication only. Group 2 patients received medication plus one shot of percutaneous electrical nerve stimulation. Group 3 patients received medication plus one shot of transcutaneous electrical nerve stimulation. Therapeutic effects were measured using a visual analog scale, body surface score, pain pressure threshold, and the Quebec Back Pain Disability Scale. RESULTS: Immediately after one-shot treatment, the visual analog scale improved 1.53 units and the body surface score improved 3.06 units in the percutaneous electrical nerve stimulation group. In the transcutaneous electrical nerve stimulation group, the visual analog scale improved 1.50 units and the body surface score improved 3.98 units. The improvements did not differ between the two groups. There were no differences in improvement at 3 days or 1 wk after the treatment among the three groups. CONCLUSIONS: Simple one-shot treatment with percutaneous electrical nerve stimulation or transcutaneous electrical nerve stimulation provided immediate pain relief for low back pain patients. One-shot transcutaneous electrical nerve stimulation treatment is recommended due to the rarity of side effects and its convenient application.     

神经肌肉电刺激同步经皮神经电刺激治疗神经根型颈椎病的疗效观察

目的：观察神经肌肉电刺激（NMES）同步经皮神经电刺激（TENS）对神经根型颈椎病的疗效。方法：72例符合入组条件的神经根型颈椎病（CSR）患者,按Excel产生的随机数字随机分成3组：NMES组（n=24）、TENS组（n=24）、同步组（n=24）。NMES组予颈肩部NMES治疗同步麻木侧上肢安慰TENS治疗;TENS组予颈肩部安慰NMES治疗同步麻木侧上肢TENS治疗;同步组予颈肩部NMES治疗同步麻木侧上肢TENS治疗。每天1次,每次20min,连续治疗14天。分别在治疗前、治疗7次、14次及1个月后比较田中靖久颈椎病症状量表评分（TZCS）、颈椎功能障碍指数（NDI）评分及正中神经和尺神经F波传导速度、生活质量（SF-36）,并观察14次治疗后的痊愈率和总有效率。结果：3组治疗前各项评分结果无显著性差异（P>0.05）。14次治疗后,同步组痊愈率69.57%,高于NMES组（40.91%）、TENS组（34.78%）(P<0.0167)。在TZCS、NDI、神经传导功能、生活质量（SF-36）评分方面,第14次治疗后即刻及治疗后1个月随访时同步组优于NMES组、T...     

Treatment of migraine attacks by transcutaneous electrical nerve stimulation in emergency department: A randomize controlled trial

PurposeThe primary purpose of this trial is to evaluate the effectiveness of Transcutaneous Electrical Nerve Stimulation (TENS) therapy application in the emergency department.MethodsThe patients were divided into 2 groups: a sham group, and a verum group. Patients in the verum group include those who use the device for the first time. Both groups were connected to visually indistinguishable devices. Both groups underwent therapy for a total of 20 min. Using the Visual Analog Scale (VAS), the patients' perceived changes in pain intensity were recorded at the 20th and 120th minutes after initiation therapy. After the 120th minute, patients' individual needs for additional treatment were assessed. Additionally, their self-reported well-being was assessed using a Likert-type verbal scale.ResultsIn total 151 patients that were admitted to the emergency ward were assessed, with the sham and verum group being assigned 39 patients each from this pool. For the verum group the VAS change from 0 to 120 min was −65 ± 25 and for the sham group it was −9 ± 2 (p < 0.001). Verbal scores in the 120th minute were found to be 1.2 for sham group and 4.5 in the verum group (p < 0.001). Thirty patients (76.92%) in the sham group and 1 (2%) in the verum group had additional analgesic requirement after 120 min.ConclusionTENS therapy is a fast-acting, effective therapy for the treatment of acute migraine in the emergency department.     

Chronic pain therapy with transcutaneous electrical nerve stimulation: predictive value of questionnaires

A retrospective study of 200 chronic pain patients was conducted to determine whether preexisting physical or social factors influence treatment success with transcutaneous electrical nerve stimulation (TENS). Responses to 30 questions from a preadmission questionnaire were analyzed against short-term treatment success. Patients with pain of more than a year's duration, who had undergone multiple surgical operations for pain control, who used tranquilizers, or who were not working because of pain, demonstrated a generally lower rate of treatment success, although the differences were not statistically significant. Treatment success rate was significantly higher for retired patients than for those with blue-collar jobs or those who were unemployed. There was no association between treatment success rate and site, frequency, character or severity of pain, age, sex, use of narcotic analgesics, or the presence of financial compensation or litigation. The value of TENS for chronic pain remains largely empirical.     

Effect of transcutaneous electrical nerve stimulation characteristics on clinical pain

We compared the effects of four treatment variables on the pain reduction produced by transcutaneous electrical nerve stimulation and attempted to establish indications for TENS based on patient history and pain evaluation items. Treatment variables were the therapist and the three TENS stimulus characteristics--pulse width, frequency, and amplitude. We randomly assigned 192 consecutive adult patients suffering from painful conditions to one of four physical therapists and one of 12 stimulus characteristic combinations. We used a standard evaluation form that included a visual analog scale (VAS) to evaluate pain. Patients were given a 30-minute trial using TENS, followed by reevaluation. The VAS line length change after treatment was the criterion score for comparison of stimulus characteristic effectiveness. Although pain was reduced greatly with TENS (p = .01), a four-way analysis of variance (pulse width, frequency, amplitude, and therapist) attributed little of the treatment effect to the treatment variables or their interactions (r2 = .101). The amplitude effect, however, was borderline (p = .056), and subthreshold stimulation proved more effective than stimulation to tolerance (p = .05). Extensive multiple linear regression analyses failed to provide indications for TENS based on patient information and pain evaluation items. Therefore, pain remains the only indication for TENS, and we recommend subthreshold rather than higher amplitude stimulation on the initial TENS trial.     

The effect of interferential therapy upon cutaneous blood flow in humans

The aim of the current controlled and blinded study was to investigate the effect of various interferential current frequencies upon cutaneous blood flow in humans using laser Doppler flowmetry, in an attempt to define the physiological mechanisms involved. Following approval from the university’s ethical committee, 50 healthy volunteers (25 male, 25 female; age 18–34 years) were randomly allocated into one of five experimental groups: (i) control; neither suction nor interferential current was applied, (ii) placebo; suction only was applied, (iii) IFT 1; 10–100 Hz beat frequency applied, (iv) IFT 2; 80–100 Hz beat frequency applied, and (v) IFT 3; 10–20 Hz beat frequency applied. In the IFT groups, interferential currents were applied through four suction electrodes positioned to target the quadriceps femoris muscle. The following parameters were used in all IFT groups: 125 μs pulse duration, 4 kHz carrier frequency and a 6/6 sweep. In IFT groups 1 and 2 only, the rotating vector system was made active. Ambient and skin temperatures were measured concomitantly. Repeated‐measures ANOVA showed a significant difference between groups (P=0·0361) and over time (P=0·0001) for blood flow data; one‐factor ANOVA showed a significant increase in blood flow in the IFT 3 group (10–20 Hz) when compared to all experimental groups at 12 min (P=0·0156). In addition, at 21 min, there were significant differences between the IFT 3 group and all other groups except control (P=0·0213). Statistical analysis of skin temperature data demonstrated significant differences over time (P=0·0001) and a significant interactive effect (P=0·0022), with no significant differences observed between groups. These findings provide some evidence of a putative vasodilatory effect caused by interferential current therapy when applied through suction electrodes at a modulated frequency of 10–20 Hz.