An examination of the analgesic effects of microcurrent electrical stimulation (MES) on cold-induced pain in healthy subjects

Efficacy of microcurrent therapy for treatment of acute knee pain: A randomized double-blinded controlled clinical trial

Objective:

We would like to determine whether electrotherapy, specifically microcurrent therapy, increases function and decreases pain in people who have acute knee pain.

Design:

Randomized, double-blinded, placebo-controlled clinical trial.

Setting:

University laboratory and patient home.

Subjects:

A total of 52 subjects (35 females and 17 males) with acute knee pain.

Intervention:

Treatment group (n = 26) wore the active microcurrent therapy device at home for 3 hours per day for 4 weeks and the control group (n = 26) wore the placebo for 3 hours per day for 4 weeks.

Main Measures:

Numeric Pain Rating Scale (NPRS) and Short Form 12 (SF-12) health scale were used to measure the pain level and the functionality of the participants. Secondary assessments included musculoskeletal ultrasound imaging (MSK US) and Lower Extremity Functional Scale (LEFS).

Results:

A total of 52 subjects completed the study; 26 in the treatment group and 26 in the control group. Microcurrent therapy significantly reduced pain over 4 weeks. Especially week three was significant (P < 0.01) after adjusting for the family-wise error rate. The analysis on SF-12 revealed those with microcurrent therapy showed an increasing trend in the improvement of physical function score until week three.

Conclusion:

An active microcurrent therapy device decreased knee pain and increased function. Microcurrent therapy may be an alternative or used with a pharmacological approach for people with acute knee pain.

Estimulação elétrica nervosa transcutânea nas modalidades convencional e acupuntura na dor induzida pelo frio

A estimulação elétrica nervosa transcutânea (TENS) é um recurso não-farmacológico já consagrado na modulação de dores agudas e crônicas. O objetivo deste estudo foi verificar o efeito da TENS convencional e na modalidade TENS-acupuntura na dor induzida pelo frio. Trinta indivíduos saudáveis com idade entre 18 e 40 anos foram distribuídos ao acaso em três grupos: placebo, TENS convencional e TENS-acupuntura. Foi utilizado um protocolo de indução de dor pelo frio composto por seis ciclos: dois pré-tratamento, dois durante e dois após o tratamento. A TENS foi aplicada por 20 minutos por dois canais, sendo a modalidade convencional, no nível sensorial, na freqüência de 80 Hz e a modalidade acupuntura, no nível motor, a 4 Hz. Foram medidos limiar de dor, tolerância à dor e intensidade da dor. Não foi encontrada diferença estatisticamente significante nos valores medidos durante a após o tratamento quando comparados aos dos ciclos pré-tratamento, em todas as variáveis. Nas duas modalidades estudadas pois, a TENS, nos parâmetros de aplicação utilizados, não modificou a dor induzida por frio, sugerindo-se novos estudos com maior tempo de aplicação da TENS e diferentes modelos de dor experimental.

An investigation into the analgesic effects of different frequencies of the amplitude-modulated wave of interferential current therapy on cold-induced pain in normal subjects 11No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit on the authors or any organization with which the authors are associated

OBJECTIVE

To investigate the analgesic effects of different amplitude-modulated frequencies of interferential current therapy (IFT) on cold-induced pain in healthy subjects.

DESIGN

Single-blind parallel group methodology was used. Subjects completed 6 cycles of the cold-induced pain test (2 pretreatment, 2 during treatment, 2 posttreatment). During each cycle, subjects plunged their hand into iced water and the time taken to reach pain threshold was recorded. The hand remained immersed in the iced water for a further 30 seconds, after which the self-reports of pain intensity and pain unpleasantness were recorded.

SETTING

Laboratory in the United Kingdom.

PARTICIPANTS

Sixty unpaid, pain-free volunteers without a known pathology that could cause pain.

INTERVENTIONS

IFT delivered on the nondominant arm at a "strong but comfortable" intensity without visible muscle twitches, using a quadripolar application technique at 1 of 6 possible amplitude modulated "beat" frequencies (20, 60, 100, 140, 180, 220Hz).

MAIN OUTCOME MEASURES

The percentage change in pain threshold, pain intensity, and pain unpleasantness from the pretreatment baseline.

RESULTS

Two-way repeated-measures analyses of variance found no effects for groups for pain threshold (P=.11) or pain ratings (P>.05). There were no effects for cycle for any of the outcome measures. Effects for group by cycle interaction were noted for pain intensity and unpleasantness ratings (P<.05), although post hoc analysis failed to determine the nature of this interaction.

CONCLUSIONS

Experimentally induced cold pain was not influenced by IFT frequencies.